Science.gov

Sample records for phosphatidylserine targets single-walled

  1. Targeting single-walled carbon nanotubes for the treatment of breast cancer using photothermal therapy

    NASA Astrophysics Data System (ADS)

    Neves, Luis Filipe Ferreira

    To develop a therapeutic system with cancer cell selectivity, the present study evaluated a possible specific and localized tumor treatment. Phosphatidylserine (PS) exposure on the external face of the cell membrane is almost completely exclusive to cancer cells and endothelial cells in the tumor vasculature. The human protein annexin V is known to have strong calcium-dependent binding to anionic phospholipids such as PS. This protein was studied for targeting single-walled carbon nanotubes (SWNTs) to the vasculature of breast tumors. The synthesis of the protein annexin V, by a pET vector in Escherichia coli, constitutes the first phase of this study. Recombinant annexin V was purified from the cell lysate supernatant by immobilized metal affinity chromatography. The overall production of purified annexin V protein was 50 mg/L. The binding ability of the protein annexin V was evaluated by determining the dissociation constant when incubated with proliferating human endothelial cells in vitro. The dissociation constant, Kd, was measured to be 0.8 nM, indicating relatively strong binding. This value of Kd is within the range reported in the literature. Single-walled carbon nanotubes (SWNTs) were functionalized with annexin V using two intermediate linkers (containing FMOC and DSPE) resulting in stable suspensions. The SWNT and protein concentrations were 202 mg/L and 515 mg/L, respectively, using the linker with DSPE (average of nine preparations). The conjugation method that used the DSPE-PEG-maleimide linker allowed to successfully conjugate the SWNTs with final concentrations approximately five times higher than the linker containing FMOC. The conjugation method used has a non-covalent nature, and therefore the optical properties of the nanotubes were preserved. The conjugate was also visually observed using atomic force microscopy (AFM), allowing to verify the presence of the protein annexin V on the surface of the nanotubes, with an height ranging between 2

  2. Imaging of Brain Tumors With Paramagnetic Vesicles Targeted to Phosphatidylserine

    PubMed Central

    Winter, Patrick M.; Pearce, John; Chu, Zhengtao; McPherson, Christopher M.; Takigiku, Ray; Lee, Jing-Huei; Qi, Xiaoyang

    2014-01-01

    Purpose To investigate paramagnetic saposin C and dioleylphosphatidylserine (SapC-DOPS) vesicles as a targeted contrast agent for imaging phosphatidylserine (PS) expressed by glioblastoma multiforme (GBM) tumors. Materials and Methods Gd-DTPA-BSA/SapC-DOPS vesicles were formulated, and the vesicle diameter and relaxivity were measured. Targeting of Gd-DTPA-BSA/ SapC-DOPS vesicles to tumor cells in vitro and in vivo was compared with nontargeted paramagnetic vesicles (lacking SapC). Mice with GBM brain tumors were imaged at 3, 10, 20, and 24 h postinjection to measure the relaxation rate (R1) in the tumor and the normal brain. Results The mean diameter of vesicles was 175 nm, and the relaxivity at 7 Tesla was 3.32 (s*mM)−1 relative to the gadolinium concentration. Gd-DTPA-BSA/SapC-DOPS vesicles targeted cultured cancer cells, leading to an increased R1 and gadolinium level in the cells. In vivo, Gd-DTPA-BSA/SapC-DOPS vesicles produced a 9% increase in the R1 of GBM brain tumors in mice 10 h postinjection, but only minimal changes (1.2% increase) in the normal brain. Nontargeted paramagnetic vesicles yielded minimal change in the tumor R1 at 10 h postinjection (1.3%). Conclusion These experiments demonstrate that Gd-DTPA-BSA/SapC-DOPS vesicles can selectively target implanted brain tumors in vivo, providing noninvasive mapping of the cancer biomarker PS. PMID:24797437

  3. Hyaluronic acid-functionalized single-walled carbon nanotubes as tumor-targeting MRI contrast agent

    PubMed Central

    Hou, Lin; Zhang, Huijuan; Wang, Yating; Wang, Lili; Yang, Xiaomin; Zhang, Zhenzhong

    2015-01-01

    A tumor-targeting carrier, hyaluronic acid (HA)-functionalized single-walled carbon nanotubes (SWCNTs), was explored to deliver magnetic resonance imaging (MRI) contrast agents (CAs) targeting to the tumor cells specifically. In this system, HA surface modification for SWCNTs was simply accomplished by amidation process and could make this nanomaterial highly hydrophilic. Cellular uptake was performed to evaluate the intracellular transport capabilities of HA-SWCNTs for tumor cells and the uptake rank was HA-SWCNTs> SWCNTs owing to the presence of HA, which was also evidenced by flow cytometry. The safety evaluation of this MRI CAs was investigated in vitro and in vivo. It revealed that HA-SWCNTs could stand as a biocompatible nanocarrier and gadolinium (Gd)/HA-SWCNTs demonstrated almost no toxicity compared with free GdCl3. Moreover, GdCl3 bearing HA-SWCNTs could significantly increase the circulation time for MRI. Finally, to investigate the MRI contrast enhancing capabilities of Gd/HA-SWCNTs, T1-weighted MR images of tumor-bearing mice were acquired. The results suggested Gd/HA-SWCNTs had the highest tumor-targeting efficiency and T1-relaxivity enhancement, indicating HA-SWCNTs could be developed as a tumor-targeting carrier to deliver the CAs, GdCl3, for the identifiable diagnosis of tumor. PMID:26213465

  4. Functionalized Single-Walled Carbon Nanotubes as Rationally Designed Vehicles for Tumor-Targeted Drug Delivery

    SciTech Connect

    Chen,J.; Wong,S.; Chen, S.; Zhao, X.; Kuznetsova, L.V.; and Ojima, I.

    2008-11-14

    A novel single-walled carbon nanotube (SWNT)-based tumor-targeted drug delivery system (DDS) has been developed, which consists of a functionalized SWNT linked to tumor-targeting modules as well as prodrug modules. There are three key features of this nanoscale DDS: (a) use of functionalized SWNTs as a biocompatible platform for the delivery of therapeutic drugs or diagnostics, (b) conjugation of prodrug modules of an anticancer agent (taxoid with a cleavable linker) that is activated to its cytotoxic form inside the tumor cells upon internalization and in situ drug release, and (c) attachment of tumor-recognition modules (biotin and a spacer) to the nanotube surface. To prove the efficacy of this DDS, three fluorescent and fluorogenic molecular probes were designed, synthesized, characterized, and subjected to the analysis of the receptor-mediated endocytosis and drug release inside the cancer cells (L1210FR leukemia cell line) by means of confocal fluorescence microscopy. The specificity and cytotoxicity of the conjugate have also been assessed and compared with L1210 and human noncancerous cell lines. Then, it has unambiguously been proven that this tumor-targeting DDS works exactly as designed and shows high potency toward specific cancer cell lines, thereby forming a solid foundation for further development.

  5. Chinese medicine single-walled carbon nanotube targeting compound for antitumor therapy: a feasible way?

    PubMed

    Li, Yun-long; Li, Jie; Yan, Chun-yin; Lai, Ze-feng; Hu, Gui-jie

    2014-01-01

    Malignant cancer is the leading cause of death in man, exceeding cerebrovascular disease and heart disease. More than half of the total mortality due to malignant cancer is from lung, liver, intestinal and gastric cancer. Chemotherapy is one of the effective treatments for cancer. However, the great majority of Western anticancer medicines have considerable side effects. Herbal medicines offer many more advantages than synthesized compounds because they are made from purely natural compounds and have less adverse effects. However, the single administration methods used as standard in herbal medicine, and deficient drug targeting, severely limit their anticancer activity. Single-walled carbon nanotubes (SWNTs) can be used as drug carriers. They have been modified to form Chinese anticancer medicine-SWNT compounds which can specifically target tumors, thereby significantly increasing the therapeutic effectiveness of these medicines. Water-soluble SWNTs have high stability. As a drug carrier, SWNTs functional modification of the anticancer medicine may improve the targeting and killing of tumor cells. SWNTs have been attached to the Chinese antitumor medicines paclitaxel and plumbagin and have achieved excellent therapeutic effects. Furthermore, choosing the best administration methods such as internal iliac arterial infusion, intravesical infusion and embedment of a hypodermic chemotherapeutic pump, may also improve the anticancer effects of Chinese medicine. PMID:22370871

  6. Vascular targeted single-walled carbon nanotubes for near-infrared light therapy of cancer

    NASA Astrophysics Data System (ADS)

    Prickett, Whitney M.; Van Rite, Brent D.; Resasco, Daniel E.; Harrison, Roger G.

    2011-11-01

    A new approach for targeting carbon nanotubes to the tumor vasculature was tested using human endothelial cells and MCF-7 breast cancer cells in vitro. Single-walled carbon nanotubes were functionalized with the F3 peptide using a polyethylene glycol linker to target nucleolin, a protein found on the surface of endothelial cells in the vasculature of solid tumors. Confocal microscopy and Raman analysis confirmed that the conjugate was internalized by actively dividing endothelial cells. Dividing endothelial cells were used to mimic these cells in the tumor vasculature. Incubation with the conjugate for 8 h or more caused significant cell death in both actively dividing endothelial cells and MCF-7 breast cancer cells, an effect that is hypothesized to be due to the massive uptake of the conjugate. This targeted cell killing was further enhanced when coupled with near-infrared laser treatment. For confluent (non-dividing) endothelial cells, no cytotoxic effect was seen for incubation alone or incubation coupled with laser treatment. These results are promising and warrant further studies using this conjugate for cancer treatment in vivo.

  7. Functional single-walled carbon nanotubes/chitosan conjugate for tumor cells targeting

    NASA Astrophysics Data System (ADS)

    Wu, Baoyan; Ou, Zhongmin; Xing, Da

    2009-08-01

    The application of single-walled carbon nanotubes (SWCNTs) in the field of biomedicine is becoming an exciting topic because of their flexible structure and propensity for chemical functionalization. In this assay, a novel noncovalently functional SWCNTs based on a natural biocompatible polymer chitosan has been developed for tumor cells targeting. First, SWCNTs were modified by chitosan (CHIT-SWCNT). Second, CHIT-SWCNT was coupled with fluorescein isothiocyanate (FITC), based on the reaction between the isothiocyanate group of FITC and the primary amino group of chitosan. Third, the FITC functionalized CHIT-SWCNT was conjugated with folic acid (FA) after activation with EDC/NHS, based on the reaction between the NHS group of FA and the primary free amino group of chitosan to construct the functional SWCNT/CHIT conjugate, CHIT-SWCNT-FA. The fluorescence CHIT-SWCNT-FA has been used to detect tumor cells with confocal microscopy imaging technology. Our experimental results indicate that the novel CHIT-SWCNT-FA is soluble and stable in PBS, and it can be readily transported inside tumor cells. Combining the intrinsic properties of carbon nanotubes and the versatility of chitosan, CHIT-SWCNT can be used as potential devices for targeted drug delivery and tumor cell sensing. The proposed assay could provide a feasible alternative to presently available functional SWCNTs in biological applications.

  8. Physical consequences of the mitochondrial targeting of single-walled carbon nanotubes probed computationally

    NASA Astrophysics Data System (ADS)

    Chistyakov, V. A.; Zolotukhin, P. V.; Prazdnova, E. V.; Alperovich, I.; Soldatov, A. V.

    2015-06-01

    Experiments by F. Zhou and coworkers (2010) [16] showed that mitochondria are the main target of the cellular accumulation of single-walled carbon nanotubes (SWCNTs). Our in silico experiments, based on geometrical optimization of the system consisting of SWCNT+proton within Density Functional Theory, revealed that protons can bind to the outer side of SWCNT so generating a positive charge. Calculation results allow one to propose the following mechanism of SWCNTs mitochondrial targeting. SWCNTs enter the space between inner and outer membranes of mitochondria, where the excess of protons has been formed by diffusion. In this compartment SWCNTs are loaded with protons and acquire positive charges distributed over their surface. Protonation of hydrophobic SWCNTs can also be carried out within the mitochondrial membrane through interaction with the protonated ubiquinone. Such "charge loaded" particles can be transferred as "Sculachev ions" through the inner membrane of the mitochondria due to the potential difference generated by the inner membrane. Physiological consequences of the described mechanism are discussed.

  9. Plasmonic welded single walled carbon nanotubes on monolayer graphene for sensing target protein

    NASA Astrophysics Data System (ADS)

    Kim, Jangheon; Kim, Gi Gyu; Kim, Soohyun; Jung, Wonsuk

    2016-05-01

    We developed plasmonic welded single walled carbon nanotubes (SWCNTs) on monolayer graphene as a biosensor to detect target antigen molecules, fc fusion protein without any treatment to generate binder groups for linker and antibody. This plasmonic welding induces atomic networks between SWCNTs as junctions containing carboxylic groups and improves the electrical sensitivity of a SWCNTs and the graphene membrane to detect target protein. We investigated generation of the atomic networks between SWCNTs by field-emission scanning electron microscopy and atomic force microscopy after plasmonic welding process. We compared the intensity ratios of D to G peaks from the Raman spectra and electrical sheet resistance of welded SWCNTs with the results of normal SWCNTs, which decreased from 0.115 to 0.086 and from 10.5 to 4.12, respectively. Additionally, we measured the drain current via source/drain voltage after binding of the antigen to the antibody molecules. This electrical sensitivity of the welded SWCNTs was 1.55 times larger than normal SWCNTs.

  10. Targeting single-walled carbon nanotubes for the treatment of breast cancer using photothermal therapy

    NASA Astrophysics Data System (ADS)

    Neves, Luís F. F.; Krais, John J.; Van Rite, Brent D.; Ramesh, Rajagopal; Resasco, Daniel E.; Harrison, Roger G.

    2013-09-01

    This paper focuses on the targeting of single-walled carbon nanotubes (SWNTs) for the treatment of breast cancer with minimal side effects using photothermal therapy. The human protein annexin V (AV) binds specifically to anionic phospholipids expressed externally on the surface of tumour cells and endothelial cells that line the tumour vasculature. A 2 h incubation of the SWNT-AV conjugate with proliferating endothelial cells followed by washing and near-infrared (NIR) irradiation at a wavelength of 980 nm was enough to induce significant cell death; there was no significant cell death with irradiation or the conjugate alone. Administration of the same conjugate i.v. in BALB/c female mice with implanted 4T1 murine mammary at a dose of 0.8 mg SWNT kg-1 and followed one day later by NIR irradiation of the tumour at a wavelength of 980 nm led to complete disappearance of implanted 4T1 mouse mammary tumours for the majority of the animals by 11 days since the irradiation. The combination of the photothermal therapy with the immunoadjuvant cyclophosphamide resulted in increased survival. The in vivo results suggest the SWNT-AV/NIR treatment is a promising approach to treat breast cancer.

  11. Targeting single-walled carbon nanotubes for the treatment of breast cancer using photothermal therapy.

    PubMed

    Neves, Luís F F; Krais, John J; Van Rite, Brent D; Ramesh, Rajagopal; Resasco, Daniel E; Harrison, Roger G

    2013-09-20

    This paper focuses on the targeting of single-walled carbon nanotubes (SWNTs) for the treatment of breast cancer with minimal side effects using photothermal therapy. The human protein annexin V (AV) binds specifically to anionic phospholipids expressed externally on the surface of tumour cells and endothelial cells that line the tumour vasculature. A 2 h incubation of the SWNT-AV conjugate with proliferating endothelial cells followed by washing and near-infrared (NIR) irradiation at a wavelength of 980 nm was enough to induce significant cell death; there was no significant cell death with irradiation or the conjugate alone. Administration of the same conjugate i.v. in BALB/c female mice with implanted 4T1 murine mammary at a dose of 0.8 mg SWNT kg(-1) and followed one day later by NIR irradiation of the tumour at a wavelength of 980 nm led to complete disappearance of implanted 4T1 mouse mammary tumours for the majority of the animals by 11 days since the irradiation. The combination of the photothermal therapy with the immunoadjuvant cyclophosphamide resulted in increased survival. The in vivo results suggest the SWNT-AV/NIR treatment is a promising approach to treat breast cancer. PMID:23975064

  12. Phosphatidylserine-selective targeting and anticancer effects of SapC-DOPS nanovesicles on brain tumors.

    PubMed

    Blanco, Víctor M; Chu, Zhengtao; Vallabhapurapu, Subrahmanya D; Sulaiman, Mahaboob K; Kendler, Ady; Rixe, Olivier; Warnick, Ronald E; Franco, Robert S; Qi, Xiaoyang

    2014-08-30

    Brain tumors, either primary (e.g., glioblastoma multiforme) or secondary (metastatic), remain among the most intractable and fatal of all cancers. We have shown that nanovesicles consisting of Saposin C (SapC) and dioleylphosphatidylserine (DOPS) are able to effectively target and kill cancer cells both in vitro and in vivo. These actions are a consequence of the affinity of SapC-DOPS for phosphatidylserine, an acidic phospholipid abundantly present in the outer membrane of a variety of tumor cells and tumor-associated vasculature. In this study, we first characterize SapC-DOPS bioavailability and antitumor effects on human glioblastoma xenografts, and confirm SapC-DOPS specificity towards phosphatidylserine by showing that glioblastoma targeting is abrogated after in vivo exposure to lactadherin, which binds phosphatidylserine with high affinity. Second, we demonstrate that SapC-DOPS selectively targets brain metastases-forming cancer cells both in vitro, in co-cultures with human astrocytes, and in vivo, in mouse models of brain metastases derived from human breast or lung cancer cells. Third, we demonstrate that SapC-DOPS have cytotoxic activity against metastatic breast cancer cells in vitro, and prolong the survival of mice harboring brain metastases. Taken together, these results support the potential of SapC-DOPS for the diagnosis and therapy of primary and metastatic brain tumors. PMID:25051370

  13. Phosphatidylserine-selective targeting and anticancer effects of SapC-DOPS nanovesicles on brain tumors

    PubMed Central

    Blanco, Víctor M.; Chu, Zhengtao; Vallabhapurapu, Subrahmanya D.; Sulaiman, Mahaboob K.; Kendler, Ady; Rixe, Olivier; Warnick, Ronald E.; Franco, Robert S.; Qi, Xiaoyang

    2014-01-01

    Brain tumors, either primary (e.g., glioblastoma multiforme) or secondary (metastatic), remain among the most intractable and fatal of all cancers. We have shown that nanovesicles consisting of Saposin C (SapC) and dioleylphosphatidylserine (DOPS) are able to effectively target and kill cancer cells both in vitro and in vivo. These actions are a consequence of the affinity of SapC-DOPS for phosphatidylserine, an acidic phospholipid abundantly present in the outer membrane of a variety of tumor cells and tumor-associated vasculature. In this study, we first characterize SapC-DOPS bioavailability and antitumor effects on human glioblastoma xenografts, and confirm SapC-DOPS specificity towards phosphatidylserine by showing that glioblastoma targeting is abrogated after in vivo exposure to lactadherin, which binds phosphatidylserine with high affinity. Second, we demonstrate that SapC-DOPS selectively targets brain metastases-forming cancer cells both in vitro, in co-cultures with human astrocytes, and in vivo, in mouse models of brain metastases derived from human breast or lung cancer cells. Third, we demonstrate that SapC-DOPS nanovesicles have cytotoxic activity against metastatic breast cancer cells in vitro, and prolong the survival of mice harboring brain metastases. Taken together, these results support the potential of SapC-DOPS for the diagnosis and therapy of primary and metastatic brain tumors. PMID:25051370

  14. Deep, noninvasive imaging and surgical guidance of submillimeter tumors using targeted M13-stabilized single-walled carbon nanotubes.

    PubMed

    Ghosh, Debadyuti; Bagley, Alexander F; Na, Young Jeong; Birrer, Michael J; Bhatia, Sangeeta N; Belcher, Angela M

    2014-09-23

    Highly sensitive detection of small, deep tumors for early diagnosis and surgical interventions remains a challenge for conventional imaging modalities. Second-window near-infrared light (NIR2, 950-1,400 nm) is promising for in vivo fluorescence imaging due to deep tissue penetration and low tissue autofluorescence. With their intrinsic fluorescence in the NIR2 regime and lack of photobleaching, single-walled carbon nanotubes (SWNTs) are potentially attractive contrast agents to detect tumors. Here, targeted M13 virus-stabilized SWNTs are used to visualize deep, disseminated tumors in vivo. This targeted nanoprobe, which uses M13 to stably display both tumor-targeting peptides and an SWNT imaging probe, demonstrates excellent tumor-to-background uptake and exhibits higher signal-to-noise performance compared with visible and near-infrared (NIR1) dyes for delineating tumor nodules. Detection and excision of tumors by a gynecological surgeon improved with SWNT image guidance and led to the identification of submillimeter tumors. Collectively, these findings demonstrate the promise of targeted SWNT nanoprobes for noninvasive disease monitoring and guided surgery. PMID:25214538

  15. Functionalized Single-Walled Carbon Nanotube-Based Fuel Cell Benchmarked Against US DOE 2017 Technical Targets

    PubMed Central

    Jha, Neetu; Ramesh, Palanisamy; Bekyarova, Elena; Tian, Xiaojuan; Wang, Feihu; Itkis, Mikhail E.; Haddon, Robert C.

    2013-01-01

    Chemically modified single-walled carbon nanotubes (SWNTs) with varying degrees of functionalization were utilized for the fabrication of SWNT thin film catalyst support layers (CSLs) in polymer electrolyte membrane fuel cells (PEMFCs), which were suitable for benchmarking against the US DOE 2017 targets. Use of the optimum level of SWNT -COOH functionality allowed the construction of a prototype SWNT-based PEMFC with total Pt loading of 0.06 mgPt/cm2 - well below the value of 0.125 mgPt/cm2 set as the US DOE 2017 technical target for total Pt group metals (PGM) loading. This prototype PEMFC also approaches the technical target for the total Pt content per kW of power (<0.125 gPGM/kW) at cell potential 0.65 V: a value of 0.15 gPt/kW was achieved at 80°C/22 psig testing conditions, which was further reduced to 0.12 gPt/kW at 35 psig back pressure. PMID:23877112

  16. Targeted delivery and controlled release of Paclitaxel for the treatment of lung cancer using single-walled carbon nanotubes.

    PubMed

    Yu, Baodan; Tan, Li; Zheng, Runhui; Tan, Huo; Zheng, Lixia

    2016-11-01

    A new type of drug delivery system (DDS) based on single-walled carbon nanotubes (SWNTs) for controlled-release of the anti-cancer drug Paclitaxel (PTX) was constructed in this study. Chitosan (CHI) was non-covalently attached to the SWNTs to improve biocompatibility. Biocompatible hyaluronan was also combined to the outer CHI layer to realise the specific targeting property. The results showed that the release of PTX was pH-triggered and was better at lower pH (pH5.5). The modified SWNTs showed a significant improvement in intracellular reactive oxygen species (ROS), which may have enhanced mitogen-activated protein kinase activation and further promoted cell apoptosis. The results of western blotting indicated that the apoptosis-related proteins were abundantly expressed in A549 cells. Lactate dehydrogenase (LDH) release assay and cell viability assay demonstrated that PTX-loaded SWNTs could destroy cell membrane integrity, thus inducing lower cell viability of the A549 cells. Thus, this targeting DDS could effectively inhibit cell proliferation and kill A549 cells, is a promising system for cancer therapy. PMID:27524057

  17. Octa-ammonium POSS-conjugated single-walled carbon nanotubes as vehicles for targeted delivery of paclitaxel

    PubMed Central

    Naderi, Naghmeh; Madani, Seyed Y.; Mosahebi, Afshin; Seifalian, Alexander M.

    2015-01-01

    Background Carbon nanotubes (CNTs) have unique physical and chemical properties. Furthermore, novel properties can be developed by attachment or encapsulation of functional groups. These unique properties facilitate the use of CNTs in drug delivery. We developed a new nanomedicine consisting of a nanocarrier, cell-targeting molecule, and chemotherapeutic drug and assessed its efficacy in vitro. Methods The efficacy of a single-walled carbon nanotubes (SWCNTs)-based nanoconjugate system is assessed in the targeted delivery of paclitaxel (PTX) to cancer cells. SWCNTs were oxidized and reacted with octa-ammonium polyhedral oligomeric silsesquioxanes (octa-ammonium POSS) to render them biocompatible and water dispersable. The functionalized SWCNTs were loaded with PTX, a chemotherapeutic agent toxic to cancer cells, and Tn218 antibodies for cancer cell targeting. The nanohybrid composites were characterized with transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and ultraviolet–visible–near-infrared (UV–Vis–NIR). Additionally, their cytotoxic effects on Colon cancer cell (HT-29) and Breast cancer cell (MCF-7) lines were assessed in vitro. Results TEM, FTIR, and UV–Vis–NIR studies confirmed side-wall functionalization of SWCNT with COOH-groups, PTX, POSS, and antibodies. Increased cell death was observed with PTX–POSS–SWCNT, PTX–POSS–Ab–SWCNT, and free PTX compared to functionalized-SWCNT (f-SWCNT), POSS–SWCNT, and cell-only controls at 48 and 72 h time intervals in both cell lines. At all time intervals, there was no significant cell death in the POSS–SWCNT samples compared to cell-only controls. Conclusion The PTX-based nanocomposites were shown to be as cytotoxic as free PTX. This important finding indicates successful release of PTX from the nanocomposites and further reiterates the potential of SWCNTs to deliver drugs directly to targeted cells and tissues. PMID:26356347

  18. Synthesis and evaluation of single-wall carbon nanotube-paclitaxel-folic acid conjugate as an anti-cancer targeting agent.

    PubMed

    Tavakolifard, Sara; Biazar, Esmaeil; Pourshamsian, Khalil; Moslemin, Mohammad H

    2016-08-01

    Single-wall carbon nanotubes (SWCNT) represent a novel nanomaterial applied in various nanotechnology fields because of their surface chemistry properties and high drug cargo capacity. In this study, SWCNT are pre-functionalized covalently with paclitaxel (PTX) - an anticancer drug, and folic acid (FA), as a targeting agent for many tumors. The samples are investigated and evaluated by different analyses such as Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), absorption spectroscopic measurements (UV-Visible), elemental analysis, and cell analyses with cancer cell line cultures. The results show good conjugation of the targeting molecule and the anticancer drug on the surface of the carbon nanotubes (CNT). This work demonstrates that the SWCNT-PTX-FA system is a potentially useful system for the targeted delivery of anticancer drugs. PMID:25783856

  19. M13 phage-functionalized single-walled carbon nanotubes as nanoprobes for second near-infrared window fluorescence imaging of targeted tumors

    PubMed Central

    HAM, MOON-HO; QI, JIFA; BARONE, PAUL W.; STRANO, MICHAEL S.; BELCHER, ANGELA M.

    2014-01-01

    Second near-infrared (NIR) window light (950-1,400 nm) is attractive for in vivo fluorescence imaging due to its deep penetration depth in tissues and low tissue autofluorescence. Here we show genetically engineered multifunctional M13 phage can assemble fluorescent single-walled carbon nanotubes (SWNTs) and ligands for targeted fluorescence imaging of tumors. M13-SWNT probe is detectable in deep tissues even at a low dosage of 2 μg/mL and up to 2.5 cm in tissue-like phantoms. Moreover, targeted probes show specific and up to four-fold improved uptake in prostate specific membrane antigen positive prostate tumors compared to control non-targeted probes. This M13 phage-based second NIR window fluorescence imaging probe has great potential for specific detection and therapy monitoring of hard-to-detect areas. PMID:22268625

  20. Global Phospholipidomics Analysis Reveals Selective Pulmonary Peroxidation Profiles Upon Inhalation of Single Walled Carbon Nanotubes

    PubMed Central

    Tyurina, Yulia Y.; Kisin, Elena R.; Murray, Ashley; Tyurin, Vladimir A.; Kapralova, Valentina I.; Sparvero, Louis J.; Amoscato, Andrew A.; Samhan-Arias, Alejandro K.; Swedin, Linda; Lahesmaa, Riitta; Fadeel, Bengt; Shvedova, Anna A.; Kagan, Valerian E.

    2011-01-01

    It is commonly believed that nanomaterials cause non-specific oxidative damage. Our mass spectrometry-based oxidative lipidomics analysis of all major phospholipid classes revealed highly selective patterns of pulmonary peroxidation after inhalation exposure of mice to single-walled carbon nanotubes. No oxidized molecular species were found in two most abundant phospholipid classes – phosphatidylcholine and phosphatidylethanolamine. Peroxidation products were identified in three relatively minor classes of anionic phospholipids, cardiolipin, phosphatidylserine and phosphatidylinositol whereby oxygenation of polyunsaturated fatty acid residues also showed unusual substrate specificity. This non-random peroxidation coincided with the accumulation of apoptotic cells in the lung. A similar selective phospholipid peroxidation profile was detected upon incubation of a mixture of total lung lipids with H2O2/cytochrome c known to catalyze cardiolipin and phosphatidylserine peroxidation in apoptotic cells. The characterized specific phospholipid peroxidation signaling pathways indicate new approaches to the development of mitochondria targeted regulators of cardiolipin peroxidation to protect against deleterious effects of pro-apoptotic effects of single-walled carbon nanotubes in the lung. PMID:21800898

  1. Global phospholipidomics analysis reveals selective pulmonary peroxidation profiles upon inhalation of single-walled carbon nanotubes.

    PubMed

    Tyurina, Yulia Y; Kisin, Elena R; Murray, Ashley; Tyurin, Vladimir A; Kapralova, Valentina I; Sparvero, Louis J; Amoscato, Andrew A; Samhan-Arias, Alejandro K; Swedin, Linda; Lahesmaa, Riitta; Fadeel, Bengt; Shvedova, Anna A; Kagan, Valerian E

    2011-09-27

    It is commonly believed that nanomaterials cause nonspecific oxidative damage. Our mass spectrometry-based oxidative lipidomics analysis of all major phospholipid classes revealed highly selective patterns of pulmonary peroxidation after inhalation exposure of mice to single-walled carbon nanotubes. No oxidized molecular species were found in the two most abundant phospholipid classes: phosphatidylcholine and phosphatidylethanolamine. Peroxidation products were identified in three relatively minor classes of anionic phospholipids, cardiolipin, phosphatidylserine, and phosphatidylinositol, whereby oxygenation of polyunsaturated fatty acid residues also showed unusual substrate specificity. This nonrandom peroxidation coincided with the accumulation of apoptotic cells in the lung. A similar selective phospholipid peroxidation profile was detected upon incubation of a mixture of total lung lipids with H(2)O(2)/cytochrome c known to catalyze cardiolipin and phosphatidylserine peroxidation in apoptotic cells. The characterized specific phospholipid peroxidation signaling pathways indicate new approaches to the development of mitochondria-targeted regulators of cardiolipin peroxidation to protect against deleterious effects of pro-apoptotic effects of single-walled carbon nanotubes in the lung. PMID:21800898

  2. Accelerated killing of cancer cells using a multifunctional single-walled carbon nanotube-based system for targeted drug delivery in combination with photothermal therapy

    PubMed Central

    Jeyamohan, Prashanti; Hasumura, Takashi; Nagaoka, Yutaka; Yoshida, Yasuhiko; Maekawa, Toru; Kumar, D Sakthi

    2013-01-01

    The photothermal effect of single-walled carbon nanotubes (SWCNTs) in combination with the anticancer drug doxorubicin (DOX) for targeting and accelerated destruction of breast cancer cells is demonstrated in this paper. A targeted drug-delivery system was developed for selective killing of breast cancer cells with polyethylene glycol biofunctionalized and DOX-loaded SWCNTs conjugated with folic acid. In our work, in vitro drug-release studies showed that the drug (DOX) binds at physiological pH (pH 7.4) and is released only at a lower pH, ie, lysosomal pH (pH 4.0), which is the characteristic pH of the tumor environment. A sustained release of DOX from the SWCNTs was observed for a period of 3 days. SWCNTs have strong optical absorbance in the near-infrared (NIR) region. In this special spectral window, biological systems are highly transparent. Our study reports that under laser irradiation at 800 nm, SWCNTs exhibited strong light–heat transfer characteristics. These optical properties of SWCNTs open the way for selective photothermal ablation in cancer therapy. It was also observed that internalization and uptake of folate-conjugated NTs into cancer cells was achieved by a receptor-mediated endocytosis mechanism. Results of the in vitro experiments show that laser was effective in destroying the cancer cells, while sparing the normal cells. When the above laser effect was combined with DOX-conjugated SWCNTs, we found enhanced and accelerated killing of breast cancer cells. Thus, this nanodrug-delivery system, consisting of laser, drug, and SWCNTs, looks to be a promising selective modality with high treatment efficacy and low side effects for cancer therapy. PMID:23926428

  3. Phosphatidylserine (PS) Is Exposed in Choroidal Neovascular Endothelium: PS-Targeting Antibodies Inhibit Choroidal Angiogenesis In Vivo and Ex Vivo

    PubMed Central

    Li, Tao; Aredo, Bogale; Zhang, Kaiyan; Zhong, Xin; Pulido, Jose S.; Wang, Shusheng; He, Yu-Guang; Huang, Xianming; Brekken, Rolf A.; Ufret-Vincenty, Rafael L.

    2015-01-01

    Purpose Choroidal neovascularization (CNV) accounts for 90% of cases of severe vision loss in patients with advanced age-related macular degeneration. Identifying new therapeutic targets for CNV may lead to novel combination therapies to improve outcomes and reduce treatment burden. Our goal was to test whether phosphatidylserine (PS) becomes exposed in the outer membrane of choroidal neovascular endothelium, and whether this could provide a new therapeutic target for CNV. Methods Choroidal neovascularization was induced in C57BL/6J mice using laser photocoagulation. Choroidal neovascularization lesions costained for exposed PS and for intercellular adhesion molecule 2 (or isolectin B4) were imaged in flat mounts and in cross sections. The laser CNV model and a choroidal sprouting assay were used to test the effect of PS-targeting antibodies on choroidal angiogenesis. Choroidal neovascularization lesion size was determined by intercellular adhesion molecule 2 (ICAM-2) staining of flat mounts. Results We found that PS was exposed in CNV lesions and colocalized with vascular endothelial staining. Treatment with PS-targeting antibodies led to a 40% to 80% reduction in CNV lesion area when compared to treatment with a control antibody. The effect was the same as that seen using an equal dose of an anti-VEGF antibody. Results were confirmed using the choroid sprouting assay, an ex vivo model of choroidal angiogenesis. Conclusions We demonstrated that PS is exposed in choroidal neovascular endothelium. Furthermore, targeting this exposed PS with antibodies may be of therapeutic value in CNV. PMID:26529048

  4. Melanoma cell surface-expressed phosphatidylserine as a therapeutic target for cationic anticancer peptide, temporin-1CEa.

    PubMed

    Wang, Che; Chen, Yin-Wang; Zhang, Liang; Gong, Xian-Ge; Zhou, Yang; Shang, De-Jing

    2016-07-01

    We have previously reported that temporin-1CEa, a cationic antimicrobial peptide, exerts preferential cytotoxicity toward cancer cells. However, the exact molecular mechanism for this cancer-selectivity is still largely unknown. Here, we found that the negatively charged phosphatidylserine (PS) expressed on cancer cell surface serves as a target for temporin-1CEa. Our results indicate that human A375 melanoma cells express 50-fold more PS than non-cancerous HaCaT cells. The expression of cell surface PS in various cancer cell lines closely correlated with their ability to be recognized, bound and killed by temporin-1CEa. Additionally, the cytotoxicity of temporin-1CEa against A375 cells can be ameliorated by annexin V, which binds to cell surface PS with high affinity. Moreover, the data of isothermal titration calorimetry assay further confirmed a direct binding of temporin-1CEa to PS, at a ratio of 1:5 (temporin-1CEa:PS). Interestingly, the circular dichroism spectra analysis using artificial biomembrane revealed that PS not only provides electrostatic attractive sites for temporin-1CEa but also confers the membrane-bound temporin-1CEa to form α-helical structure, therefore, enhances the affinity and membrane disrupting ability of temporin-1CEa. In summary, these findings suggested that the melanoma cells expressed PS may serve as a promising target for temporin-1CEa or other cationic anticancer peptides. PMID:26596643

  5. Targeted detection of phosphatidylserine in biomimetic membranes and in vitro cell systems using annexin V-containing cubosomes.

    PubMed

    Shen, Hsin-Hui; Lake, Vanessa; Le Brun, Anton P; James, Michael; Duff, Anthony P; Peng, Yong; McLean, Keith M; Hartley, Patrick G

    2013-11-01

    In this work we have formulated Annexin V (ANX) decorated phosphatidylserine containing phytantriol (PSPhy) cubosomes to act as probes for the enhanced detection of apoptotic membranes in both model and in vitro cell systems. Small angle X-ray scattering (SAXS) and cryogenic-transmission electron microscopy (Cryo-TEM) indicated that ANX-containing PSPhy (ANX-PSPhy) cubosomes retain the Pn3m cubic symmetry and cubic phase nanoparticle characteristics of PSPhy cubosomes. The interaction of ANX-PSPhy cubosomes with apoptotic model and cellular membranes was also investigated using both quartz crystal microbalance with dissipation and confocal microscopy which confirmed that ANX-PSPhy cubosomes can selectively bind to apoptotic cells and model membranes. Neutron reflectometry has also been used to show strong binding of ANX-PSPhy cubosomes to a model apoptotic membrane, and in addition reveals changes in both the bilayer structure and in the internal structure of the cubosome in a region adjacent to the membrane as a result of material exchange. This material exchange between cubosome and apoptotic model bilayer was further demonstrated using Cryo-TEM. We have demonstrated that lipid bound protein, in this case Annexin V, can be used to target cubosome systems to biological surfaces in vitro. PMID:23899446

  6. Single wall penetration equations

    NASA Technical Reports Server (NTRS)

    Hayashida, K. B.; Robinson, J. H.

    1991-01-01

    Five single plate penetration equations are compared for accuracy and effectiveness. These five equations are two well-known equations (Fish-Summers and Schmidt-Holsapple), two equations developed by the Apollo project (Rockwell and Johnson Space Center (JSC), and one recently revised from JSC (Cour-Palais). They were derived from test results, with velocities ranging up to 8 km/s. Microsoft Excel software was used to construct a spreadsheet to calculate the diameters and masses of projectiles for various velocities, varying the material properties of both projectile and target for the five single plate penetration equations. The results were plotted on diameter versus velocity graphs for ballistic and spallation limits using Cricket Graph software, for velocities ranging from 2 to 15 km/s defined for the orbital debris. First, these equations were compared to each other, then each equation was compared with various aluminum projectile densities. Finally, these equations were compared with test results performed at JSC for the Marshall Space Flight Center. These equations predict a wide variety of projectile diameters at a given velocity. Thus, it is very difficult to choose the 'right' prediction equation. The thickness of a single plate could have a large variation by choosing a different penetration equation. Even though all five equations are empirically developed with various materials, especially for aluminum alloys, one cannot be confident in the shield design with the predictions obtained by the penetration equations without verifying by tests.

  7. Tumor-specific targeting by Bavituximab, a phosphatidylserine-targeting monoclonal antibody with vascular targeting and immune modulating properties, in lung cancer xenografts.

    PubMed

    Gerber, David E; Hao, Guiyang; Watkins, Linda; Stafford, Jason H; Anderson, Jon; Holbein, Blair; Öz, Orhan K; Mathews, Dana; Thorpe, Philip E; Hassan, Gedaa; Kumar, Amit; Brekken, Rolf A; Sun, Xiankai

    2015-01-01

    Bavituximab is a chimeric monoclonal antibody with immune modulating and tumor-associated vascular disrupting properties demonstrated in models of non-small cell lung cancer (NSCLC). The molecular target of Bavituximab, phosphatidylserine (PS), is exposed on the outer leaflet of the membrane bi-layer of malignant vascular endothelial cells and tumor cells to a greater extent than on normal tissues. We evaluated the tumor-targeting properties of Bavituximab for imaging of NSCLC xenografts when radiolabeled with (111)In through conjugation with a bifunctional chelating agent, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). In vitro binding of (111)In-DOTA-Bavituximab to PS was determined by enzyme-linked immunosorbent assay (ELISA). Biodistribution of (111)In-DOTA-Bavituximab was conducted in normal rats, which provided data for dosimetry calculation. Single-photon emission computed tomography/computed tomography (SPECT/CT) imaging was performed in athymic nude rats bearing A549 NSCLC xenografts. At the molar conjugation ratio of 0.54 DOTA per Bavituximab, the PS binding affinity of (111)In-DOTA-Bavituximab was comparable to that of unmodified Bavituximab. Based on the quantitative SPECT/CT imaging data analysis, (111)In-DOTA-Bavituximab demonstrated tumor-specific uptake as measured by the tumor-tomuscle ratio, which peaked at 5.2 at 72 hr post-injection. In contrast, the control antibody only presented a contrast of 1.2 at the same time point.These findings may underlie the diagnostic efficacy and relative low rates of systemic vascular and immune-related toxicities of this immunoconjugate. Future applications of (111)In-DOTA-bavituximab may include prediction of efficacy, indication of tumor immunologic status, or characterization of radiographic findings. PMID:26550540

  8. Tumor-specific targeting by Bavituximab, a phosphatidylserine-targeting monoclonal antibody with vascular targeting and immune modulating properties, in lung cancer xenografts

    PubMed Central

    Gerber, David E; Hao, Guiyang; Watkins, Linda; Stafford, Jason H; Anderson, Jon; Holbein, Blair; Öz, Orhan K; Mathews, Dana; Thorpe, Philip E; Hassan, Gedaa; Kumar, Amit; Brekken, Rolf A; Sun, Xiankai

    2015-01-01

    Bavituximab is a chimeric monoclonal antibody with immune modulating and tumor-associated vascular disrupting properties demonstrated in models of non-small cell lung cancer (NSCLC). The molecular target of Bavituximab, phosphatidylserine (PS), is exposed on the outer leaflet of the membrane bi-layer of malignant vascular endothelial cells and tumor cells to a greater extent than on normal tissues. We evaluated the tumor-targeting properties of Bavituximab for imaging of NSCLC xenografts when radiolabeled with 111In through conjugation with a bifunctional chelating agent, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). In vitro binding of 111In-DOTA-Bavituximab to PS was determined by enzyme-linked immunosorbent assay (ELISA). Biodistribution of 111In-DOTA-Bavituximab was conducted in normal rats, which provided data for dosimetry calculation. Single-photon emission computed tomography/computed tomography (SPECT/CT) imaging was performed in athymic nude rats bearing A549 NSCLC xenografts. At the molar conjugation ratio of 0.54 DOTA per Bavituximab, the PS binding affinity of 111In-DOTA-Bavituximab was comparable to that of unmodified Bavituximab. Based on the quantitative SPECT/CT imaging data analysis, 111In-DOTA-Bavituximab demonstrated tumor-specific uptake as measured by the tumor-tomuscle ratio, which peaked at 5.2 at 72 hr post-injection. In contrast, the control antibody only presented a contrast of 1.2 at the same time point.These findings may underlie the diagnostic efficacy and relative low rates of systemic vascular and immune-related toxicities of this immunoconjugate. Future applications of 111In-DOTA-bavituximab may include prediction of efficacy, indication of tumor immunologic status, or characterization of radiographic findings. PMID:26550540

  9. Human lactoferricin derived di-peptides deploying loop structures induce apoptosis specifically in cancer cells through targeting membranous phosphatidylserine.

    PubMed

    Riedl, Sabrina; Leber, Regina; Rinner, Beate; Schaider, Helmut; Lohner, Karl; Zweytick, Dagmar

    2015-11-01

    Host defense-derived peptides have emerged as a novel strategy for the development of alternative anticancer therapies. In this study we report on characteristic features of human lactoferricin (hLFcin) derivatives which facilitate specific killing of cancer cells of melanoma, glioblastoma and rhabdomyosarcoma compared with non-specific derivatives and the synthetic peptide RW-AH. Changes in amino acid sequence of hLFcin providing 9-11 amino acids stretched derivatives LF11-316, -318 and -322 only yielded low antitumor activity. However, the addition of the repeat (di-peptide) and the retro-repeat (di-retro-peptide) sequences highly improved cancer cell toxicity up to 100% at 20 μM peptide concentration. Compared to the complete parent sequence hLFcin the derivatives showed toxicity on the melanoma cell line A375 increased by 10-fold and on the glioblastoma cell line U-87mg by 2-3-fold. Reduced killing velocity, apoptotic blebbing, activation of caspase 3/7 and formation of apoptotic DNA fragments proved that the active and cancer selective peptides, e.g. R-DIM-P-LF11-322, trigger apoptosis, whereas highly active, though non-selective peptides, such as DIM-LF11-318 and RW-AH seem to kill rapidly via necrosis inducing membrane lyses. Structural studies revealed specific toxicity on cancer cells by peptide derivatives with loop structures, whereas non-specific peptides comprised α-helical structures without loop. Model studies with the cancer membrane mimic phosphatidylserine (PS) gave strong evidence that PS only exposed by cancer cells is an important target for specific hLFcin derivatives. Other negatively charged membrane exposed molecules as sialic acid, heparan and chondroitin sulfate were shown to have minor impact on peptide activity. PMID:26239537

  10. Ballistic Limit Equation for Single Wall Titanium

    NASA Technical Reports Server (NTRS)

    Ratliff, J. M.; Christiansen, Eric L.; Bryant, C.

    2009-01-01

    Hypervelocity impact tests and hydrocode simulations were used to determine the ballistic limit equation (BLE) for perforation of a titanium wall, as a function of wall thickness. Two titanium alloys were considered, and separate BLEs were derived for each. Tested wall thicknesses ranged from 0.5mm to 2.0mm. The single-wall damage equation of Cour-Palais [ref. 1] was used to analyze the Ti wall's shielding effectiveness. It was concluded that the Cour-Palais single-wall equation produced a non-conservative prediction of the ballistic limit for the Ti shield. The inaccurate prediction was not a particularly surprising result; the Cour-Palais single-wall BLE contains shield material properties as parameters, but it was formulated only from tests of different aluminum alloys. Single-wall Ti shield tests were run (thicknesses of 2.0 mm, 1.5 mm, 1.0 mm, and 0.5 mm) on Ti 15-3-3-3 material custom cut from rod stock. Hypervelocity impact (HVI) tests were used to establish the failure threshold empirically, using the additional constraint that the damage scales with impact energy, as was indicated by hydrocode simulations. The criterion for shield failure was defined as no detached spall from the shield back surface during HVI. Based on the test results, which confirmed an approximately energy-dependent shield effectiveness, the Cour-Palais equation was modified.

  11. Scalable dielectrophoresis of single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Fitzhugh, William A.

    Single Walled Carbon Nanotubes (SWNTs) have attracted much attention as a candidate material for future nano-scale 'beyond silicon' devices. However industrial scale operations have been impeded by difficulties in separating the metallic and semiconducting species. This paper addresses the use of highly inhomogeneous alternating electric fields, dielectrophoresis, to isolate SWNT species in scaled systems. Both numerical and experimental methods will be discussed.

  12. Cutting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ziegler, Kirk J.; Gu, Zhenning; Shaver, Jonah; Chen, Zheyi; Flor, Erica L.; Schmidt, Daniel J.; Chan, Candace; Hauge, Robert H.; Smalley, Richard E.

    2005-07-01

    A two-step process is utilized for cutting single-walled carbon nanotubes (SWNTs). The first step requires the breakage of carbon-carbon bonds in the lattice while the second step is aimed at etching at these damage sites to create short, cut nanotubes. To achieve monodisperse lengths from any cutting strategy requires control of both steps. Room-temperature piranha and ammonium persulfate solutions have shown the ability to exploit the damage sites and etch SWNTs in a controlled manner. Despite the aggressive nature of these oxidizing solutions, the etch rate for SWNTs is relatively slow and almost no new sidewall damage is introduced. Carbon-carbon bond breakage can be introduced through fluorination to ~C2F, and subsequent etching using piranha solutions has been shown to be very effective in cutting nanotubes. The final average length of the nanotubes is approximately 100 nm with carbon yields as high as 70-80%.

  13. Molecular Imaging with Single-Walled Carbon Nanotubes

    PubMed Central

    Hong, Hao; Gao, Ting; Cai, Weibo

    2011-01-01

    Nanoparticle-based molecular imaging has emerged as an interdisciplinary field which involves physics, chemistry, engineering, biology, and medicine. Single-walled carbon nanotubes (SWCNTs) have unique properties which make them suitable for applications in a variety of imaging modalities, such as magnetic resonance, near-infrared fluorescence, Raman spectroscopy, photoacoustic tomography, and radionuclide-based imaging. In this review, we will summarize the current state-of-the-art of SWCNTs in molecular imaging applications. Multifunctionality is the key advantage of nanoparticles over traditional approaches. Targeting ligands, imaging labels, therapeutic drugs, and many other agents can all be integrated into the nanoparticle to allow for targeted molecular imaging and molecular therapy by encompassing many biological and biophysical barriers. A multifunctional, SWCNT-based nanoplatform holds great potential for clinical applications in the future. PMID:21754949

  14. Laser ablation process for single-walled carbon nanotube production

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivaram

    2004-01-01

    Different types of lasers are now routinely used to prepare single-walled carbon nanotubes. The original method developed by researchers at Rice University used a "double-pulse laser oven" process. Several researchers have used variations of the lasers to include one-laser pulse (green or infrared), different pulse widths (ns to micros as well as continuous wave), and different laser wavelengths (e.g., CO2, or free electron lasers in the near to far infrared). Some of these variations are tried with different combinations and concentrations of metal catalysts, buffer gases (e.g., helium), oven temperatures, flow conditions, and even different porosities of the graphite targets. This article is an attempt to cover all these variations and their relative merits. Possible growth mechanisms under these different conditions will also be discussed.

  15. Single Walled Carbon Nanotube/Silicon Heterojunctions

    NASA Astrophysics Data System (ADS)

    Wu, Zhuangchun

    2005-11-01

    Characterization of the electrical heterojunction between single walled carbon nanotubes (SWNTs) and semiconductors is important for an array of potential applications. Thin, homogeneous, transparent, films of 100% SWNTs exhibiting good electrical conductivity [1] have already been demonstrated as the hole injection electrode in GaN light emitting diodes [2]. The simultaneous transparency and high electrical conductivity of these films makes them similarly promising for the light transmissive electrode in photovoltaic devices. SWNTs have moreover long been proposed as on-chip, device interconnects. To understand the electrical coupling between the nanotubes and semiconductors, likely to have relevance in such devices, we have begun a systematic exploration of the electrical properties of SWNT/silicon hetrojunctions. We will discuss findings as well as a novel test method made possible by the unique morphology of the nanotubes. 1. Z. Wu, Z. Chen, X. Du, J. M. Logan, J. Sippel, M. Nikolou, K. Kamaras, J. R. Reynolds, D. B. Tanner, A. F. Hebard, A. G. Rinzler, Science 305, 1273 (2004) 2. K. Lee, Z. Wu, Z. Chen, F. Ren, S. J. Pearton, A. G. Rinzler, Nano Lett. 4, 911 (2004)

  16. Enhancement of Anti-Inflammatory Activity of Curcumin Using Phosphatidylserine-Containing Nanoparticles in Cultured Macrophages

    PubMed Central

    Wang, Ji; Kang, Yu-Xia; Pan, Wen; Lei, Wan; Feng, Bin; Wang, Xiao-Juan

    2016-01-01

    Macrophages are one kind of innate immune cells, and produce a variety of inflammatory cytokines in response to various stimuli, such as oxidized low density lipoprotein found in the pathogenesis of atherosclerosis. In this study, the effect of phosphatidylserine on anti-inflammatory activity of curcumin-loaded nanostructured lipid carriers was investigated using macrophage cultures. Different amounts of phosphatidylserine were used in the preparation of curcumin nanoparticles, their physicochemical properties and biocompatibilities were then compared. Cellular uptake of the nanoparticles was investigated using a confocal laser scanning microscope and flow cytometry analysis in order to determine the optimal phosphatidylserine concentration. In vitro anti-inflammatory activities were evaluated in macrophages to test whether curcumin and phosphatidylserine have interactive effects on macrophage lipid uptake behavior and anti-inflammatory responses. Here, we showed that macrophage uptake of phosphatidylserine-containing nanostructured lipid carriers increased with increasing amount of phosphatidylserine in the range of 0%–8%, and decreased when the phosphatidylserine molar ratio reached over 12%. curcumin-loaded nanostructured lipid carriers significantly inhibited lipid accumulation and pro-inflammatory factor production in cultured macrophages, and evidently promoted release of anti-inflammatory cytokines, when compared with curcumin or phosphatidylserine alone. These results suggest that the delivery system using PS-based nanoparticles has great potential for efficient delivery of drugs such as curcumin, specifically targeting macrophages and modulation of their anti-inflammatory functions. PMID:27331813

  17. Methods for Gas Sensing with Single-Walled Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B. (Inventor)

    2013-01-01

    Methods for gas sensing with single-walled carbon nanotubes are described. The methods comprise biasing at least one carbon nanotube and exposing to a gas environment to detect variation in temperature as an electrical response.

  18. On the Stability and Abundance of Single Walled Carbon Nanotubes

    PubMed Central

    Hedman, Daniel; Reza Barzegar, Hamid; Rosén, Arne; Wågberg, Thomas; Andreas Larsson, J.

    2015-01-01

    Many nanotechnological applications, using single-walled carbon nanotubes (SWNTs), are only possible with a uniform product. Thus, direct control over the product during chemical vapor deposition (CVD) growth of SWNT is desirable, and much effort has been made towards the ultimate goal of chirality-controlled growth of SWNTs. We have used density functional theory (DFT) to compute the stability of SWNT fragments of all chiralities in the series representing the targeted products for such applications, which we compare to the chiralities of the actual CVD products from all properly analyzed experiments. From this comparison we find that in 84% of the cases the experimental product represents chiralities among the most stable SWNT fragments (within 0.2 eV) from the computations. Our analysis shows that the diameter of the SWNT product is governed by the well-known relation to size of the catalytic nanoparticles, and the specific chirality is normally determined by the product’s relative stability, suggesting thermodynamic control at the early stage of product formation. Based on our findings, we discuss the effect of other experimental parameters on the chirality of the product. Furthermore, we highlight the possibility to produce any tube chirality in the context of recent published work on seeded-controlled growth. PMID:26581125

  19. On the Stability and Abundance of Single Walled Carbon Nanotubes.

    PubMed

    Hedman, Daniel; Reza Barzegar, Hamid; Rosén, Arne; Wågberg, Thomas; Andreas Larsson, J

    2015-01-01

    Many nanotechnological applications, using single-walled carbon nanotubes (SWNTs), are only possible with a uniform product. Thus, direct control over the product during chemical vapor deposition (CVD) growth of SWNT is desirable, and much effort has been made towards the ultimate goal of chirality-controlled growth of SWNTs. We have used density functional theory (DFT) to compute the stability of SWNT fragments of all chiralities in the series representing the targeted products for such applications, which we compare to the chiralities of the actual CVD products from all properly analyzed experiments. From this comparison we find that in 84% of the cases the experimental product represents chiralities among the most stable SWNT fragments (within 0.2 eV) from the computations. Our analysis shows that the diameter of the SWNT product is governed by the well-known relation to size of the catalytic nanoparticles, and the specific chirality is normally determined by the product's relative stability, suggesting thermodynamic control at the early stage of product formation. Based on our findings, we discuss the effect of other experimental parameters on the chirality of the product. Furthermore, we highlight the possibility to produce any tube chirality in the context of recent published work on seeded-controlled growth. PMID:26581125

  20. On the Stability and Abundance of Single Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Hedman, Daniel; Reza Barzegar, Hamid; Rosén, Arne; Wågberg, Thomas; Andreas Larsson, J.

    2015-11-01

    Many nanotechnological applications, using single-walled carbon nanotubes (SWNTs), are only possible with a uniform product. Thus, direct control over the product during chemical vapor deposition (CVD) growth of SWNT is desirable, and much effort has been made towards the ultimate goal of chirality-controlled growth of SWNTs. We have used density functional theory (DFT) to compute the stability of SWNT fragments of all chiralities in the series representing the targeted products for such applications, which we compare to the chiralities of the actual CVD products from all properly analyzed experiments. From this comparison we find that in 84% of the cases the experimental product represents chiralities among the most stable SWNT fragments (within 0.2 eV) from the computations. Our analysis shows that the diameter of the SWNT product is governed by the well-known relation to size of the catalytic nanoparticles, and the specific chirality is normally determined by the product’s relative stability, suggesting thermodynamic control at the early stage of product formation. Based on our findings, we discuss the effect of other experimental parameters on the chirality of the product. Furthermore, we highlight the possibility to produce any tube chirality in the context of recent published work on seeded-controlled growth.

  1. Phosphatidylserine-binding protein lactadherin inhibits protein translocation across the ER membrane.

    PubMed

    Yamamoto, Hitoshi; Kida, Yuichiro; Sakaguchi, Masao

    2013-05-10

    Secretory and membrane proteins are translocated across and inserted into the endoplasmic reticulum membrane via translocon channels. To investigate the effect of the negatively-charged phospholipid phosphatidylserine on the translocation of nascent polypeptide chains through the translocon, we used the phosphatidylserine-binding protein lactadherin C2-domain. Lactadherin inhibited targeting of nascent chain to the translocon by signal sequence and the initiation of translocation. Moreover, lactadherin inhibited the movement of the translocating polypeptide chain regardless of the presence or absence of positively-charged residues. Phosphatidylserine might be critically involved in translocon function, but it is not a major determinant for translocation arrest of positively-charged residues. PMID:23583395

  2. Oxidized Phosphatidylserine: Production and Bioactivities

    PubMed Central

    Matsura, Tatsuya

    2014-01-01

    Recent development of analytical methods for lipid hydroperoxides and preparation of highly pure lipid hydroperoxides have revealed the important new pathophysiological roles of oxidized phospholipids. Generation of reactive oxygen species and subsequent oxidative stress leads to random oxidation of membrane phospholipids. However, recent studies have reported that anionic phospholipid molecules such as phosphatidylserine (PS) and cardiolipin are preferentially oxidized during apoptosis, resulting in efficient apoptosis execution and apoptotic cell clearance by phagocytes. This review is exclusively focused on selective production of oxidized PS (oxPS) during apoptosis as well as the novel roles of oxPS under pathophysiological conditions. PMID:25901098

  3. Synthesis, assembly, and applications of single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Ryu, Koungmin

    This dissertation presents the synthesis and assembly of aligned carbon nanotubes, and their applications in both nano-electronics such as transistor and integrated circuits and macro-electronics in energy conversion devices as transparent conducting electrodes. Also, the high performance chemical sensor using metal oxide nanowire has been demonstrated. Chapter 1 presents a brief introduction of carbon nanotube, followed by discussion of a new synthesis technique using nanosphere lithography to grow highly aligned single-walled carbon nanotubes atop quartz and sapphire substrates. This method offers great potential to produce carbon nanotube arrays with simultaneous control over the nanotube orientation, position, density, diameter and even chirality. Chapter 3 introduces the wafer-scale integration and assembly of aligned carbon nanotubes, including full-wafer scale synthesis and transfer of massively aligned carbon nanotube arrays, and nanotube device fabrication on 4 inch Si/SiO2 wafer to yield submicron channel transistors with high on-current density ˜ 20 muA/mum and good on/off ratio and CMOS integrated circuits. In addition, various chemical doping methods for n-type nanotube transistors are studied to fabricate CMOS integrated nanotube circuits such as inverter, NAND and NOR logic devices. Furthermore, defect-tolerant circuit design for NAND and NOR is proposed and demonstrated to guarantee the correct operation of logic circuit, regardless of the presence of mis-aligned or mis-positioned nanotubes. Carbon nanotube flexible electronics and smart textiles for ubiquitous computing and sensing are demonstrated in chapter 4. A facile transfer printing technique has been introduced to transfer massively aligned single-walled carbon nanotubes from the original sapphire/quartz substrates to virtually any other substrates, including glass, silicon, polymer sheets, and even fabrics. The characterization of transferred nanotubes reveals that the transferred

  4. Chemical Sensing with Polyaniline Coated Single-Walled Carbon Nanotubes

    SciTech Connect

    Ding, Mengning; Tang, Yifan; Gou, Pingping; Reber, Michael J; Star, Alexander

    2011-01-25

    Single-walled carbon nanotube/polyaniline (SWNT/PAni) nanocomposite with controlled core/shell morphology was synthesized by a noncovalent functionalization approach. Unique electron interactions between the SWNT core and the PAni shell were studied electrochemically and spectroscopically, and superior sensor performance to chemical gases and vapors was demonstrated.

  5. Ion adsorption mechanism of bundled single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yoshida, Y.; Tsutsui, M.; Al-zubaidi, A.; Ishii, Y.; Kawasaki, S.

    2016-07-01

    In order to elucidate ion adsorption mechanism of bundled single-walled carbon nanotubes (SWCNTs), in situ synchrotron XRD measurements of SWCNT electrode in alkali halide aqueous electrolyte at several applied potentials were performed. It was found that the surface inside SWCNT is the important ion adsorption site.

  6. A Computational Experiment on Single-Walled Carbon Nanotubes

    ERIC Educational Resources Information Center

    Simpson, Scott; Lonie, David C.; Chen, Jiechen; Zurek, Eva

    2013-01-01

    A computational experiment that investigates single-walled carbon nanotubes (SWNTs) has been developed and employed in an upper-level undergraduate physical chemistry laboratory course. Computations were carried out to determine the electronic structure, radial breathing modes, and the influence of the nanotube's diameter on the…

  7. Strain Sensitivity in Single Walled Carbon Nanotubes for Multifunctional Materials

    NASA Technical Reports Server (NTRS)

    Heath, D. M. (Technical Monitor); Smits, Jan M., VI

    2005-01-01

    Single walled carbon nanotubes represent the future of structural aerospace vehicle systems due to their unparalleled strength characteristics and demonstrated multifunctionality. This multifunctionality rises from the CNT's unique capabilities for both metallic and semiconducting electron transport, electron spin polarizability, and band gap modulation under strain. By incorporating the use of electric field alignment and various lithography techniques, a single wall carbon nanotube (SWNT) test bed for measurement of conductivity/strain relationships has been developed. Nanotubes are deposited at specified locations through dielectrophoresis. The circuit is designed such that the central, current carrying section of the nanotube is exposed to enable atomic force microscopy and manipulation in situ while the transport properties of the junction are monitored. By applying this methodology to sensor development a flexible single wall carbon nanotube (SWNT) based strain sensitive device has been developed. Studies of tensile testing of the flexible SWNT device vs conductivity are also presented, demonstrating the feasibility of using single walled HiPCO (high-pressure carbon monoxide) carbon nanotubes as strain sensing agents in a multi-functional materials system.

  8. Flame Synthesis Of Single-Walled Carbon Nanotubes And Nanofibers

    NASA Technical Reports Server (NTRS)

    Wal, Randy L. Vander; Berger, Gordon M.; Ticich, Thomas M.

    2003-01-01

    Carbon nanotubes are widely sought for a variety of applications including gas storage, intercalation media, catalyst support and composite reinforcing material [1]. Each of these applications will require large scale quantities of CNTs. A second consideration is that some of these applications may require redispersal of the collected CNTs and attachment to a support structure. If the CNTs could be synthesized directly upon the support to be used in the end application, a tremendous savings in post-synthesis processing could be realized. Therein we have pursued both aerosol and supported catalyst synthesis of CNTs. Given space limitations, only the aerosol portion of the work is outlined here though results from both thrusts will be presented during the talk. Aerosol methods of SWNT, MWNT or nanofiber synthesis hold promise of large-scale production to supply the tonnage quantities these applications will require. Aerosol methods may potentially permit control of the catalyst particle size, offer continuous processing, provide highest product purity and most importantly, are scaleable. Only via economy of scale will the cost of CNTs be sufficient to realize the large-scale structural and power applications on both earth and in space. Present aerosol methods for SWNT synthesis include laser ablation of composite metalgraphite targets or thermal decomposition/pyrolysis of a sublimed or vaporized organometallic [2]. Both approaches, conducted within a high temperature furnace, have produced single-walled nanotubes (SWNTs). The former method requires sophisticated hardware and is inherently limited by the energy deposition that can be realized using pulsed laser light. The latter method, using expensive organometallics is difficult to control for SWNT synthesis given a range of gasparticle mixing conditions along variable temperature gradients; multi-walled nanotubes (MWNTs) are a far more likely end products. Both approaches require large energy expenditures and

  9. Thermionic Emission of Single-Wall Carbon Nanotubes Measured

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Krainsky, Isay L.; Bailey, Sheila G.; Elich, Jeffrey M.; Landi, Brian J.; Gennett, Thomas; Raffaelle, Ryne P.

    2004-01-01

    Researchers at the NASA Glenn Research Center, in collaboration with the Rochester Institute of Technology, have investigated the thermionic properties of high-purity, single-wall carbon nanotubes (SWNTs) for use as electron-emitting electrodes. Carbon nanotubes are a recently discovered material made from carbon atoms bonded into nanometer-scale hollow tubes. Such nanotubes have remarkable properties. An extremely high aspect ratio, as well as unique mechanical and electronic properties, make single-wall nanotubes ideal for use in a vast array of applications. Carbon nanotubes typically have diameters on the order of 1 to 2 nm. As a result, the ends have a small radius of curvature. It is these characteristics, therefore, that indicate they might be excellent potential candidates for both thermionic and field emission.

  10. Assessing the pulmonary toxicity of single-walled carbon nanohorns

    SciTech Connect

    Lynch, Rachel M; Voy, Brynn H; Glass-Mattie, Dana F; Mahurin, Shannon Mark; Saxton, Arnold; Donnel, Robert L.; Cheng, Mengdawn

    2007-01-01

    Previous studies have suggested that single-walled carbon nanotubes (SWCNTs) may pose a pulmonary hazard. We investigated the pulmonary toxicity of single-walled carbon nanohorns (SWCNHs), a relatively new carbon-based nanomaterial that is structurally similar to SWCNTs. Mice were exposed to 30 {micro}g of surfactant-suspended SWCNHs or an equal volume of vehicle control by pharyngeal aspiration and sacrificed 24 hours or 7 days post-exposure. Total and differential cell counts and cytokine analysis of bronchoalveolar lavage fluid demonstrated a mild inflammatory response which was mitigated by day 7 post-exposure. Whole lung microarray analysis demonstrated that SWCNH-exposure did not lead to robust changes in gene expression. Finally, histological analysis showed no evidence of granuloma formation or fibrosis following SWCNH aspiration. These combined results suggest that SWCNH is a relatively innocuous nanomaterial when delivered to mice in vivo using aspiration as a delivery mechanism.

  11. Structure of single-wall carbon nanotubes: a graphene helix.

    PubMed

    Lee, Jae-Kap; Lee, Sohyung; Kim, Jin-Gyu; Min, Bong-Ki; Kim, Yong-Il; Lee, Kyung-Il; An, Kay Hyeok; John, Phillip

    2014-08-27

    Evidence is presented in this paper that certain single-wall carbon nanotubes are not seamless tubes, but rather adopt a graphene helix resulting from the spiral growth of a nano-graphene ribbon. The residual traces of the helices are confirmed by high-resolution transmission electron microscopy and atomic force microscopy. The analysis also shows that the tubular graphene material may exhibit a unique armchair structure and the chirality is not a necessary condition for the growth of carbon nanotubes. The description of the structure of the helical carbon nanomaterials is generalized using the plane indices of hexagonal space groups instead of using chiral vectors. It is also proposed that the growth model, via a graphene helix, results in a ubiquitous structure of single-wall carbon nanotubes. PMID:24838196

  12. Noise characteristics of single-walled carbon nanotube network transistors

    NASA Astrophysics Data System (ADS)

    Kim, Un Jeong; Kim, Kang Hyun; Kim, Kyu Tae; Min, Yo-Sep; Park, Wanjun

    2008-07-01

    The noise characteristics of randomly networked single-walled carbon nanotubes grown directly by plasma enhanced chemical vapor deposition (PECVD) are studied with field effect transistors (FETs). Due to the geometrical complexity of nanotube networks in the channel area and the large number of tube-tube/tube-metal junctions, the inverse frequency, 1/f, dependence of the noise shows a similar level to that of a single single-walled carbon nanotube transistor. Detailed analysis is performed with the parameters of number of mobile carriers and mobility in the different environment. This shows that the change in the number of mobile carriers resulting in the mobility change due to adsorption and desorption of gas molecules (mostly oxygen molecules) to the tube surface is a key factor in the 1/f noise level for carbon nanotube network transistors.

  13. Noise characteristics of single-walled carbon nanotube network transistors.

    PubMed

    Kim, Un Jeong; Kim, Kang Hyun; Kim, Kyu Tae; Min, Yo-Sep; Park, Wanjun

    2008-07-16

    The noise characteristics of randomly networked single-walled carbon nanotubes grown directly by plasma enhanced chemical vapor deposition (PECVD) are studied with field effect transistors (FETs). Due to the geometrical complexity of nanotube networks in the channel area and the large number of tube-tube/tube-metal junctions, the inverse frequency, 1/f, dependence of the noise shows a similar level to that of a single single-walled carbon nanotube transistor. Detailed analysis is performed with the parameters of number of mobile carriers and mobility in the different environment. This shows that the change in the number of mobile carriers resulting in the mobility change due to adsorption and desorption of gas molecules (mostly oxygen molecules) to the tube surface is a key factor in the 1/f noise level for carbon nanotube network transistors. PMID:21828739

  14. Reinforcement of Epoxies Using Single Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Krishnamoorti, Ramanan; Sharma, Jitendra; Chatterjee, Tirtha

    2008-03-01

    The reinforcement of bisphenol-A and bisphenol-F epoxies using single walled carbon nanotubes has been approached experimentally by understanding the nature of interactions between the matrices and nanotubes. Unassisted dispersions of single walled carbon nanotubes in epoxies were studied by a combination of radiation scattering (elastic small angle scattering and inelastic scattering), DSC based glass transition determination, melt rheology and solid-state mechanical testing in order to understand and correlate changes in local and global dynamics to the tailoring of composite mechanical properties. Significant changes in the glass transition temperature of the matrix can successfully account for changes in the viscoelastic properties of the epoxy dispersions for concentrations below the percolation threshold, while above the percolation threshold the network superstructure formed by the nanotubes controls the viscoelastic properties.

  15. Reversible separation of single-walled carbon nanotubes in bundles

    SciTech Connect

    Sahoo, Sangeeta; Lastella, Sarah; Maranganti, Ravi; Sharma, Pradeep; Mallick, Govind; Karna, Shashi; Ajayan, Pulickel M.

    2008-08-25

    We show that electrostatic charging of nanotubes and the consequent repulsion can lead to reversible separation of individual single-walled carbon nanotubes in bundles. Low-energy electron beam irradiation leads to this completely reversible phenomenon. A simple semianalytical model is used to explain the observed separation mechanism. The reversibility of the separation process is attributed to discharging and thermal-fluctuation induced motion of the nanotubes in ambient air. Further, the separation impacts the electrical conductance of small nanotube bundled devices.

  16. Metallic single-walled carbon nanotubes for conductive nanocomposites.

    PubMed

    Wang, Wei; Fernando, K A Shiral; Lin, Yi; Meziani, Mohammed J; Veca, L Monica; Cao, Li; Zhang, Puyu; Kimani, Martin M; Sun, Ya-Ping

    2008-01-30

    This article reports an unambiguous demonstration that bulk-separated metallic single-walled carbon nanotubes offer superior performance (consistently and substantially better than the as-produced nanotube sample) in conductive composites with poly(3-hexylthiophene) and also in transparent conductive coatings based on PEDOT:PSS. The results serve as a validation on the widely held view that the carbon nanotubes are competitive in various technologies currently dominated by conductive inorganic materials (such as indium tin oxide). PMID:18173271

  17. Synthesis of Single-Wall Carbon Nanotubes from Diesel Soot

    NASA Astrophysics Data System (ADS)

    Uchida, Takashi; Ohashi, Ouji; Kawamoto, Hironori; Yoshimura, Hirofumi; Kobayashi, Ken-ichi; Tanimura, Makoto; Fujikawa, Naohiro; Nishimoto, Tetsuro; Awata, Kazuhiko; Tachibana, Masaru; Kojima, Kenichi

    2006-10-01

    We show that diesel soot can be recycled as a carbon source for the synthesis of single-wall carbon nanotubes (SWNTs). The synthesis of SWNTs was carried out by the laser vaporization of diesel soot. The presence of SWNTs was confirmed by Raman spectroscopy and transmission electron microscopy. SWNTs produced in this way should provide economic benefits and also contribute to a cleaner environment.

  18. Quantitative optical imaging of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Herman, Lihong H.

    The development and application of optical imaging tools and probing techniques have been the subject of exciting research. These tools and techniques allow for non-invasive, simple sample preparation and relatively fast measurement of electronic and optical properties. They also provided crucial information on optoelectronic device application and development. As the field of nanostructure research emerged, they were modified and employed to understand various properties of these structures at the diffraction limit of light. Carbon nanotubes, up to hundreds of micrometers long and several nanometers thin, are perfect for testing and demonstrating newly-developed optical measurement platforms for individual nanostructures, due to their heterogeneous nature. By employing two quantitative imaging techniques, wide-field on-chip Rayleigh scattering spectroscopy and spatial modulation confocal absorption microscopy, we investigate the optical properties of single-walled carbon nanotubes. These techniques allow us to obtain the Rayleigh scattering intensity, absolute absorption cross section, spatial resolution, and spectral information of single-walled carbon nanotubes. By probing the optical resonance of hundreds of single-walled carbon nanotubes in a single measurement, the first technique utilizes Rayleigh scattering mechanism to obtain the chirality of carbon nanotubes. The second technique, by using high numerical aperture oil immersion objective lenses, we measure the absolute absorption cross section of a single-walled carbon nanotube. Combining all the quantitative values obtained from these techniques, we observe various interesting and recently discovered physical behaviors, such as long range optical coupling and universal optical conductivity on resonance, and demonstrate the possibility of accurate quantitative absorption measurement for individual structures at nanometer scale.

  19. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

    2010-01-01

    An improved protocol for thermogravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material. In most cases, TGA of carbon nanotube materials is performed in gas mixtures that contain oxygen at various concentrations. The improved protocol is summarized.

  20. Symmetry Properties of Single-Walled BC2N Nanotubes

    SciTech Connect

    Pan, Hui; Feng, Yuan Ping; Lin, Jainyi

    2009-06-01

    The symmetry properties of the single-walled BC2N nanotubes were investigated. All the BC2N nanotubes possess nonsymmorphic line groups. In contrast with the carbon and boron nitride nanotubes, armchair and zigzag BC2N nanotubes belong to different line groups, depending on the index n (even or odd) and the vector chosen. The number of Raman- active phonon modes is almost twice that of the infrared-active phonon modes for all kinds of BC2N nanotubes.

  1. Modified Single-Wall Carbon Nanotubes for Reinforce Thermoplastic Polyimide

    NASA Technical Reports Server (NTRS)

    Lebron-COlon, Marisabel; Meador, Michael A.

    2006-01-01

    A significant improvement in the mechanical properties of the thermoplastic polyimide film was obtained by the addition of noncovalently functionalized single-wall carbon nanotubes (SWNTs). Polyimide films were reinforced using pristine SWNTs and functionalized SWNTs (F-SWNTs). The tensile strengths of the polyimide films containing F-SWNTs were found to be approximately 1.4 times higher than those prepared from pristine SWNTs.

  2. Titanium dioxide, single-walled carbon nanotube composites

    DOEpatents

    Yao, Yuan; Li, Gonghu; Gray, Kimberly; Lueptow, Richard M.

    2015-07-14

    The present invention provides titanium dioxide/single-walled carbon nanotube composites (TiO.sub.2/SWCNTs), articles of manufacture, and methods of making and using such composites. In certain embodiments, the present invention provides membrane filters and ceramic articles that are coated with TiO.sub.2/SWCNT composite material. In other embodiments, the present invention provides methods of using TiO.sub.2/SWCNT composite material to purify a sample, such as a water or air sample.

  3. Production of single-walled carbon nanotube grids

    DOEpatents

    Hauge, Robert H; Xu, Ya-Qiong; Pheasant, Sean

    2013-12-03

    A method of forming a nanotube grid includes placing a plurality of catalyst nanoparticles on a grid framework, contacting the catalyst nanoparticles with a gas mixture that includes hydrogen and a carbon source in a reaction chamber, forming an activated gas from the gas mixture, heating the grid framework and activated gas, and controlling a growth time to generate a single-wall carbon nanotube array radially about the grid framework. A filter membrane may be produced by this method.

  4. Dynamic terahertz polarization in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Xu, X. L.; Parkinson, P.; Chuang, K.-C.; Johnston, M. B.; Nicholas, R. J.; Herz, L. M.

    2010-08-01

    We have investigated the anisotropic dynamic dielectric response of aligned and well-isolated single-walled carbon nanotubes using optical-pump terahertz (THz)-probe techniques. The polarization anisotropy measurements demonstrate that the THz radiation interacts only with radiation polarized parallel to the nanotubes which have been selectively excited by a polarized pump pulse thus allowing controlled THz polarization to be achieved from unaligned nanotubes.

  5. Stamping single wall nanotubes for circuit quantum electrodynamics

    SciTech Connect

    Viennot, J. J. Kontos, T.; Palomo, J.

    2014-03-17

    We report on a dry transfer technique for single wall carbon nanotube devices, which allows to embed them in high finesse microwave cavity. We demonstrate the ground state charge readout and a quality factor of about 3000 down to the single photon regime. This technique allows to make devices such as double quantum dots, which could be instrumental for achieving the strong spin photon coupling. It can easily be extended to generic carbon nanotube based microwave devices.

  6. Chromatographic size separation of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Duesberg, G. S.; Muster, J.; Krstic, V.; Burghard, M.; Roth, S.

    The efficient purification of single-wall carbon nanotubes (SWNTs) is reported. Carbon nanospheres, metal particles, and amorphous carbon could be successfully removed by size exclusion chromatography (SEC) applied to surfactant stabilised dispersions of SWNT raw material. In addition, length separation of the tubes was achieved. The SWNTs obtained can be adsorbed in high densities onto chemically modified substrates. As determined by AFM investigations, the purified material consists of about equal fractions of both individual SWNTS and ropes of SWNTs.

  7. Selective uptake of single-walled carbon nanotubes by circulating monocytes for enhanced tumour delivery

    NASA Astrophysics Data System (ADS)

    Smith, Bryan Ronain; Ghosn, Eliver Eid Bou; Rallapalli, Harikrishna; Prescher, Jennifer A.; Larson, Timothy; Herzenberg, Leonore A.; Gambhir, Sanjiv Sam

    2014-06-01

    In cancer imaging, nanoparticle biodistribution is typically visualized in living subjects using `bulk' imaging modalities such as magnetic resonance imaging, computerized tomography and whole-body fluorescence. Accordingly, nanoparticle influx is observed only macroscopically, and the mechanisms by which they target cancer remain elusive. Nanoparticles are assumed to accumulate via several targeting mechanisms, particularly extravasation (leakage into tumour). Here, we show that, in addition to conventional nanoparticle-uptake mechanisms, single-walled carbon nanotubes are almost exclusively taken up by a single immune cell subset, Ly-6Chi monocytes (almost 100% uptake in Ly-6Chi monocytes, below 3% in all other circulating cells), and delivered to the tumour in mice. We also demonstrate that a targeting ligand (RGD) conjugated to nanotubes significantly enhances the number of single-walled carbon nanotube-loaded monocytes reaching the tumour (P < 0.001, day 7 post-injection). The remarkable selectivity of this tumour-targeting mechanism demonstrates an advanced immune-based delivery strategy for enhancing specific tumour delivery with substantial penetration.

  8. Fabrication of Dense Horizontally Aligned Arrays of Single-Wall Carbon Nanotubes from Vertically Aligned Arrays

    NASA Astrophysics Data System (ADS)

    Zheng, Gang; Wang, Xueshen; Li, Qunqing; Xie, Jing; Zhu, Zhendong; Zou, Yuan; Liu, Junku; Jiang, Kaili; Fan, Shoushan

    2011-01-01

    The as-grown vertically aligned single-wall carbon nanotube (SWNT) arrays are transferred from the original silicon substrate to a poly(ethylene terephthalate) (PET) substrate, which acts as a stamp. Thin SWNT films can be applied from the stamp to the target substrate and subsequently treated by an ultrasonic process to reduce their thickness to 6.6 nm. The transferred SWNT thin film retains the advantageous super-alignment and high-density properties of the vertical SWNT arrays. The linear density, transmittance, and square resistance of the thin film are as high as 15 tubes per micrometer, 99% at 550 nm, and 16 kΩ, respectively.

  9. Robust cyclohexanone selective chemiresistors based on single-walled carbon nanotubes.

    PubMed

    Frazier, Kelvin M; Swager, Timothy M

    2013-08-01

    Functionalized single-walled carbon nanotube (SWCNT)-based chemiresistors are reported for a highly robust and sensitive gas sensor to selectively detect cyclohexanone, a target analyte for explosive detection. The trifunctional selector has three important properties: it noncovalently functionalizes SWCNTs with cofacial π-π interactions, it binds to cyclohexanone via hydrogen bond (mechanistic studies were investigated), and it improves the overall robustness of SWCNT-based chemiresistors (e.g., humidity and heat). Our sensors produced reversible and reproducible responses in less than 30 s to 10 ppm of cyclohexanone and displayed an average theoretical limit of detection (LOD) of 5 ppm. PMID:23886453

  10. Phosphatidylserine biosynthesis in cultured Chinese hamster ovary cells. I. Inhibition of de novo phosphatidylserine biosynthesis by exogenous phosphatidylserine and its efficient incorporation

    SciTech Connect

    Nishijima, M.; Kuge, O.; Akamatsu, Y.

    1986-05-05

    The effect of phosphatidylserine exogenously added to the medium on de novo biosynthesis of phosphatidylserine was investigated in cultured Chinese hamster ovary cells. When cells were cultured for several generations in medium supplemented with phosphatidylserine and /sup 32/Pi, the incorporation of /sup 32/Pi into cellular phosphatidylserine was remarkably inhibited, the degree of inhibition being dependent upon the concentration of added phosphatidylserine. /sup 32/Pi uptake into cellular phosphatidylethanolamine was also partly reduced by the addition of exogenous phosphatidylserine, consistent with the idea that phosphatidylethanolamine is biosynthesized via decarboxylation of phosphatidylserine. However, incorporation of /sup 32/Pi into phosphatidylcholine, sphingomyelin, and phosphatidylinositol was not significantly affected. In contrast, the addition of either phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, or phosphatidylinositol to the medium did not inhibit endogenous biosynthesis of the corresponding phospholipid. Radiochemical and chemical analyses of the cellular phospholipid composition revealed that phosphatidylserine in cells grown with 80 microM phosphatidylserine was almost entirely derived from the added phospholipid. Phosphatidylserine uptake was also directly determined by using (/sup 3/H)serine-labeled phospholipid. Pulse and pulse-chase experiments with L-(U-/sup 14/C) serine showed that when cells were cultured with 80 microM phosphatidylserine, the rate of synthesis of phosphatidylserine was reduced 3-5-fold. Enzyme assaying of extracts prepared from cells grown with and without phosphatidylserine indicated that the inhibition of de novo phosphatidylserine biosynthesis by the added phosphatidylserine appeared not to be caused by a reduction in the level of the enzyme involved in the base-exchange reaction between phospholipids and serine.

  11. Improvements in Production of Single-Walled Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Balzano, Leandro; Resasco, Daniel E.

    2009-01-01

    A continuing program of research and development has been directed toward improvement of a prior batch process in which single-walled carbon nanotubes are formed by catalytic disproportionation of carbon monoxide in a fluidized-bed reactor. The overall effect of the improvements has been to make progress toward converting the process from a batch mode to a continuous mode and to scaling of production to larger quantities. Efforts have also been made to optimize associated purification and dispersion post processes to make them effective at large scales and to investigate means of incorporating the purified products into composite materials. The ultimate purpose of the program is to enable the production of high-quality single-walled carbon nanotubes in quantities large enough and at costs low enough to foster the further development of practical applications. The fluidized bed used in this process contains mixed-metal catalyst particles. The choice of the catalyst and the operating conditions is such that the yield of single-walled carbon nanotubes, relative to all forms of carbon (including carbon fibers, multi-walled carbon nanotubes, and graphite) produced in the disproportionation reaction is more than 90 weight percent. After the reaction, the nanotubes are dispersed in various solvents in preparation for end use, which typically involves blending into a plastic, ceramic, or other matrix to form a composite material. Notwithstanding the batch nature of the unmodified prior fluidized-bed process, the fluidized-bed reactor operates in a continuous mode during the process. The operation is almost entirely automated, utilizing mass flow controllers, a control computer running software specific to the process, and other equipment. Moreover, an important inherent advantage of fluidized- bed reactors in general is that solid particles can be added to and removed from fluidized beds during operation. For these reasons, the process and equipment were amenable to

  12. Metal-doped single-walled carbon nanotubes and production thereof

    DOEpatents

    Dillon, Anne C.; Heben, Michael J.; Gennett, Thomas; Parilla, Philip A.

    2007-01-09

    Metal-doped single-walled carbon nanotubes and production thereof. The metal-doped single-walled carbon nanotubes may be produced according to one embodiment of the invention by combining single-walled carbon nanotube precursor material and metal in a solution, and mixing the solution to incorporate at least a portion of the metal with the single-walled carbon nanotube precursor material. Other embodiments may comprise sputter deposition, evaporation, and other mixing techniques.

  13. Single-Walled Carbon Nanotube/PMMA Composites

    NASA Astrophysics Data System (ADS)

    Du, Fangming; Fisher, John; Winey, Karen

    2003-03-01

    Single-walled carbon nanotubes (SWNTs) have demonstrated unique mechanical, thermal and electrical properties. Similar properties are expected for polymer/SWNT nanocomposites. A new processing method has been used to produce PMMA/SWNT composites, which provides better dispersion of SWNT in the polymer matrix. Optical microscopy of the samples show improved dispersion of SWNT in the PMMA matrix, which is the key factor of the composite performance. Aligned and unaligned composite samples have been made for both purified SWNT and functionalized SWNT with different SWNT loadings. The tensile, thermal conductivity, and electroconductivity measurements of these samples will be performed.

  14. Optical Characterization and Applications of Single Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Strano, Michael S.

    2005-03-01

    Recent advances in the dispersion and separation of single walled carbon nanotubes have led to new methods of optical characterization and some novel applications. We find that Raman spectroscopy can be used to probe the aggregation state of single-walled carbon nanotubes in solution or as solids with a range of varying morphologies. Carbon nanotubes experience an orthogonal electronic dispersion when in electrical contact that broadens (from 40 meV to roughly 80 meV) and shifts the interband transition to lower energy (by 60 meV). We show that the magnitude of this shift is dependent on the extent of bundle organization and the inter-nanotube contact area. In the Raman spectrum, aggregation shifts the effective excitation profile and causes peaks to increase or decrease, depending on where the transition lies, relative to the excitation wavelength. The findings are particularly relevant for evaluating nanotube separation processes, where relative peak changes in the Raman spectrum can be confused for selective enrichment. We have also used gel electrophoresis and column chromatography conducted on individually dispersed, ultrasonicated single-walled carbon nanotubes to yield simultaneous separation by tube length and diameter. Electroelution after electrophoresis is shown to produce highly resolved fractions of nanotubes with average lengths between 92 and 435 nm. Separation by diameter is concomitant with length fractionation, and nanotubes that have been cut shortest also possess the greatest relative enrichments of large-diameter species. The relative quantum yield decreases nonlinearly as the nanotube length becomes shorter. These findings enable new applications of nanotubes as sensors and biomarkers. Particularly, molecular detection using near infrared (n-IR) light between 0.9 and 1.3 eV has important biomedical applications because of greater tissue penetration and reduced auto-fluorescent background in thick tissue or whole blood media. Carbon nanotubes

  15. Single Wall Nanotube Type-Specific Functionalization and Separation

    NASA Technical Reports Server (NTRS)

    Boul, Peter; Nikolaev, Pavel; Sosa, Edward; Arepalli, Sivaram; Yowell, Leonard

    2008-01-01

    Metallic single-wall carbon nanotubes were selectively solubilized in THF and separated from semiconducting nanotubes. Once separated, the functionalized metallic tubes were de-functionalized to restore their metallic band structure. Absorption and Raman spectroscopy of the enriched samples support conclusions of the enrichment of nanotube samples by metallic type. A scalable method for enriching nanotube conductive type has been developed. Raman and UV-Vis data indicate SWCNT reaction with dodecylbenzenediazonium results in metallic enrichment. It is expected that further refinement of this techniques will lead to more dramatic separations of types and diameters.

  16. Phonon Density of States of Single-Wall Carbon Nanotubes

    SciTech Connect

    Rols, S.; Benes, Z.; Anglaret, E.; Sauvajol, J. L.; Papanek, P.; Fischer, J. E.; Coddens, G.; Schober, H.; Dianoux, A. J.

    2000-12-11

    The vibrational density of states of single-wall carbon nanotubes (SWNT) was obtained from inelastic neutron scattering data from 0 to 225meV. The spectrum is similar to that of graphite above 40meV, while intratube features are clearly observed at 22 and 36meV. An unusual energy dependence below 10meV is assigned to contributions from intertube modes in the 2D triangular lattice of SWNT bundles, and from intertube coupling to intratube excitations. Good agreement between experiment and a calculated density of states for the SWNT lattice is found over the entire energy range.

  17. Reaction of folic acid with single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ellison, Mark D.; Chorney, Matthew

    2016-10-01

    The oxygen-containing functional groups on oxidized single-walled carbon nanotubes (SWNTs) are used to covalently bond folic acid molecules to the SWNTs. Infrared spectroscopy confirms intact molecular binding to the SWNTs through the formation of an amide bond between a carboxylic acid group on an SWNT and the primary amine group of folic acid. The folic acid-functionalized SWNTs are readily dispersible in water and phosphate-buffered saline, and the dispersions are stable for a period of two weeks or longer. These folic acid-functionalized SWNTs offer potential for use as biocompatible SWNTs.

  18. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Single-walled carbon nanotubes... Specific Chemical Substances § 721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance... single-walled carbon nanotubes (PMN P-08-328) is subject to reporting under this section for...

  19. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Single-walled carbon nanotubes... Specific Chemical Substances § 721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance... single-walled carbon nanotubes (PMN P-08-328) is subject to reporting under this section for...

  20. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Single-walled carbon nanotubes... Specific Chemical Substances § 721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance... single-walled carbon nanotubes (PMN P-08-328) is subject to reporting under this section for...

  1. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Single-walled carbon nanotubes... Specific Chemical Substances § 721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance... single-walled carbon nanotubes (PMN P-08-328) is subject to reporting under this section for...

  2. Individual single-wall carbon nanotubes as quantum wires

    NASA Astrophysics Data System (ADS)

    Tans, Sander J.; Devoret, Michel H.; Dai, Hongjie; Thess, Andreas; Smalley, Richard E.; Geerligs, L. J.; Dekker, Cees

    1997-04-01

    Carbon nanotubes have been regarded since their discovery1 as potential molecular quantum wires. In the case of multi-wall nanotubes, where many tubes are arranged in a coaxial fashion, the electrical properties of individual tubes have been shown to vary strongly from tube to tube2,3, and to be characterized by disorder and localization4. Single-wall nanotubes5,6 (SWNTs) have recently been obtained with high yields and structural uniformity7. Particular varieties of these highly symmetric structures have been predicted to be metallic, with electrical conduction occurring through only two electronic modes8-10. Because of the structural symmetry and stiffness of SWNTs, their molecular wavefunctions may extend over the entire tube. Here we report electrical transport measurements on individual single-wall nanotubes that confirm these theoretical predictions. We find that SWNTs indeed act as genuine quantum wires. Electrical conduction seems to occur through well separated, discrete electron states that are quantum-mechanically coherent over long distance, that is at least from contact to contact (140nm). Data in a magnetic field indicate shifting of these states due to the Zeeman effect.

  3. Structure-Controlled Synthesis of Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Li, Yan

    Single-walled carbon nanotubes (SWNTs) present structure-determined outstanding properties and SWNTs with a single (n, m) type are needed in many advanced applications. However, the chirality-specific growth of SWNTs is always a great challenge. Carbon nanotubes and their caps or catalysts can all act as the structural templates to guide the formation of SWNTs with a specified chirality. SWNT growth via a catalyzed chemical vapor deposition CVD process is normally more efficient and therefore of great interest. We developed a new family of catalyst, tungsten-based intermetallic nanocrystals, to grow SWNTs with specified chiral structures. Such intermetallic nanocrystals present unique structure and atomic arrangements, which are distinctly different from the normal alloy nanoparticles or simple metal nanocrystals, therefore can act as the template to grow SWNTs with designed (n, m) structures. Using W6Co7 catalysts, we realized the selective growth of (12, 6), (16, 0), (14, 4) and other chiralities. By the cooperation of thermodynamic and kinetic factors, SWNTs with high chirality purity can be obtained. . Structure-Controlled Synthesis of Single-Walled Carbon Nanotubes.

  4. Diameter-dependent solubility of single-walled carbon nanotubes.

    PubMed

    Duque, Juan G; Parra-Vasquez, A Nicholas G; Behabtu, Natnael; Green, Micah J; Higginbotham, Amanda L; Price, B Katherine; Leonard, Ashley D; Schmidt, Howard K; Lounis, Brahim; Tour, James M; Doorn, Stephen K; Cognet, Laurent; Pasquali, Matteo

    2010-06-22

    We study the solubility and dispersibility of as-produced and purified HiPco single-walled carbon nanotubes (SWNTs). Variation in specific operating conditions of the HiPco process are found to lead to significant differences in the respective SWNT solubilities in oleum and surfactant suspensions. The diameter distributions of SWNTs dispersed in surfactant solutions are batch-dependent, as evidenced by luminescence and Raman spectroscopies, but are identical for metallic and semiconducting SWNTs within a batch. We thus find that small diameter SWNTs disperse at higher concentration in aqueous surfactants and dissolve at higher concentration in oleum than do large-diameter SWNTs. These results highlight the importance of controlling SWNT synthesis methods in order to optimize processes dependent on solubility, including macroscopic processing such as fiber spinning, material reinforcement, and films production, as well as for fundamental research in type selective chemistry, optoelectronics, and nanophotonics. PMID:20521799

  5. Radiation Protection Using Single-Wall Carbon Nanotube Derivatives

    NASA Technical Reports Server (NTRS)

    Tour, James M.; Lu, Meng; Lucente-Schultz, Rebecca; Leonard, Ashley; Doyle, Condell Dewayne; Kosynkin, Dimitry V.; Price, Brandi Katherine

    2011-01-01

    This invention is a means of radiation protection, or cellular oxidative stress mitigation, via a sequence of quenching radical species using nano-engineered scaffolds, specifically single-wall carbon nanotubes (SWNTs) and their derivatives. The material can be used as a means of radiation protection by reducing the number of free radicals within, or nearby, organelles, cells, tissue, organs, or living organisms, thereby reducing the risk of damage to DNA and other cellular components (i.e., RNA, mitochondria, membranes, etc.) that can lead to chronic and/or acute pathologies, including but not limited to cancer, cardiovascular disease, immuno-suppression, and disorders of the central nervous system. In addition, this innovation could be used as a prophylactic or antidote for accidental radiation exposure, during high-altitude or space travel where exposure to radiation is anticipated, or to protect from exposure from deliberate terrorist or wartime use of radiation- containing weapons.

  6. The electrochemical properties of bundles of single-walled nanotubes

    SciTech Connect

    Zawodzinski, T.A. Jr.; Haridoss, P.; Uribe, F.A.

    1998-12-31

    This is the final report of a Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors studied electrochemical properties of single-walled fullerene nanotube bundles. The materials exhibited a highly anisotropic conductivity. Electrochemical cycling in solutions of alkyl ammonium salts in propylene carbonate revealed that the nanotubes are stable to at least {+-}1.5 V and have a fairly high accessible surface area. Double-layer charging currents of approximately 30 farads per gram were observed. This is on the same order of magnitude, though somewhat lower, than state-of-the-art values for ultra-capacitor materials. Electrochemical insertion of lithium was attempted. Though several features were observed in a slow cyclic voltammetric scan, these features were not reversible, indicating little reversible insertion. Several possible reasons for this behavior are discussed.

  7. Magnetic Fractionation and Alignment of Single Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Islam, M. F.; Milkie, D. E.; Yodh, A. G.; Kikkawa, J. M.

    2004-03-01

    We study mechanisms of single wall carbon nanotube (SWNT) alignment in a magnetic field. Through magnetic fractionation, we create SWNT suspensions with varying quantities of magnetic catalyst particles. The degree of tube alignment in magnetic fields up to 9 Tesla is quantified using polarized optical absorbance anisotropy. Continuous measurements of the nematic order parameter of these suspensions in variable magnetic fields provides a way to identify the origin of magnetic torques giving rise to nanotube alignment. Initial data suggests a transition from catalyst-driven to nanotube-anisotropy driven orientation as the catalyst fraction is reduced. We relate these results to observations of nanotube aggregation. This work has been supported by NSF through DMR-0203378, DMR-079909 and DGE-0221664, NASA through NAG8-2172, DARPA/ONR through N00014-01-1-0831, and SENS.

  8. Single Wall Carbon Nano Tube Films and Coatings

    NASA Astrophysics Data System (ADS)

    Sreekumar, T. V.; Kumar, Satish; Ericson, Lars M.; Smalley, Richard E.

    2002-03-01

    Purified single wall carbon nano tubes (SWNTs) produced from the high-pressure carbon monoxide (HiPCO) process have been dissolved /dispersed in oleum. These solutions /dispersions were optically homogeneous and have been used to form stand-alone SWNT films. The washed, dried, and heat-treated films are isotropic. The scanning electron micrographs of the film surface shows that the nanotube ropes (or fibrils) of about 20 nm diameters are arranged just like macroscopic fibers in a non-woven fabric. Polarized Raman spectroscopy of the SWNT film confirms the isotropic nature of these films. The films are being characterized for their thermal, mechanical as well electrical properties. Thin nano tube coatings, including optically transparent coatings, have also been made on a variety of substrates such as glass, polyethylene, polystyrene, polypropylene, silicon wafer, as well as stainless steel.

  9. Phonon sidebands of photoluminescence in single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yu, Guili; Liang, Qifeng; Jia, Yonglei; Dong, Jinming

    2010-01-01

    The multiphonon-assisted photoluminescence (PL) of the single wall carbon nanotubes (SWNTs) have been studied by solving the Schrödinger equation, showing a set of phonon sidebands, both the Stokes and anti-Stokes lines, which are induced by the longitudinal optical phonon and radial breathing mode phonon. All the calculated results are in a good agreement with the recent experimental PL spectra of the SWNTs [F. Plentz, H. B. Ribeiro, A. Jorio, M. S. Strano, and M. A. Pimenta, Phys. Rev. Lett. 95, 247401 (2005)] and J. Lefebvre and P. Finnie, Phys. Rev. Lett. 98, 167406 (2007)]. In addition, it is very interesting to find in the calculated PL several additional phonon sidebands with rather weak intensities, which are caused by the exciton's coupling with two kinds of phonons, and expected to be observed in future experiments.

  10. General synthesis of inorganic single-walled nanotubes

    PubMed Central

    Ni, Bing; Liu, Huiling; Wang, Peng-peng; He, Jie; Wang, Xun

    2015-01-01

    The single-walled nanotube (SWNT) is an interesting nanostructure for fundamental research and potential applications. However, very few inorganic SWNTs are available to date due to the lack of efficient fabrication methods. Here we synthesize four types of SWNT: sulfide; hydroxide; phosphate; and polyoxometalate. Each type of SWNT possesses essentially uniform diameters. Detailed studies illustrate that the formation of SWNTs is initiated by the self-coiling of the corresponding ultrathin nanostructure embryo/building blocks on the base of weak interactions between them, which is not limited to specific compounds or crystal structures. The interactions between building blocks can be modulated by varying the solvents used, thus multi-walled tubes can also be obtained. Our results reveal that the generalized synthesis of inorganic SWNTs can be achieved by the self-coiling of ultrathin building blocks under the proper weak interactions. PMID:26510862

  11. Storage of Hydrogen in Single-Walled Carbon Nanotubes

    SciTech Connect

    Dillon, A. C.; Jones, K. M.; Bekkedahl, T. A.; Kiang, C. H.; Bethune, D. S.; Heben, M. J.

    1997-03-27

    Pores of molecular dimensions can adsorb large quantities of gases owing to the enhanced density of the adsorbed material inside the pores, a consequence of the attractive potential of the pore walls. Pederson and Broughton have suggested that carbon nanotubes, which have diameters of typically a few nanometres, should be able to draw up liquids by capillarity, and this effect has been seen for low-surface-tension liquids in large-diameter, multi-walled nanotubes. Here we show that a gas can condense to high density inside narrow, single-walled nanotubes (SWNTs). Temperature-programmed desorption spectroscopy shows that hydrogen will condense inside SWNTs under conditions that do not induce adsorption within a standard mesoporous activated carbon. The very high hydrogen uptake in these materials suggests that they might be effective as a hydrogen-storage material for fuel-cell electric vehicles.

  12. Structural anisotropy of magnetically aligned single wall carbon nanotube films

    SciTech Connect

    Smith, B. W.; Benes, Z.; Luzzi, D. E.; Fischer, J. E.; Walters, D. A.; Casavant, M. J.; Schmidt, J.; Smalley, R. E.

    2000-07-31

    Thick films of aligned single wall carbon nanotubes and ropes have been produced by filtration/deposition from suspension in strong magnetic fields. We measured mosaic distributions of rope orientations in the film plane, for samples of different thicknesses. For an {approx}1 {mu}m film the full width at half maximum (FWHM) derived from electron diffraction is 25 degree sign -28 degree sign . The FWHM of a thicker film ({approx}7 {mu}m) measured by x-ray diffraction is slightly broader, 35{+-}3 degree sign . Aligned films are denser than ordinary filter-deposited ones, and much denser than as-grown material. Optimization of the process is expected to yield smaller FWHMs and higher densities. (c) 2000 American Institute of Physics.

  13. Single-Wall Carbon Nanotubes as Transparent Electrodes for Photovoltaics

    SciTech Connect

    Weeks, C.; Peltola, J.; Levitsky, I.; Glatkowski, P.; van de Lagemaat, J.; Rumbles, G.; Barnes, T.; Coutts, T.

    2006-01-01

    Transparent and electrically conductive coatings and films have a variety of uses in the fast-growing field of optoelectronic applications. Transparent electrodes typically include semiconductive metal oxides such as indium tin oxide (ITO), and conducting polymers such as poly(3,4-ethylenedioxythiophene), doped and stabilized with poly(styrenesulfonate) (PEDOT/PSS). In recent years, Eikos, Inc. has conceived and developed technologies to deliver novel alternatives using single-wall carbon nanotubes (SWNT). These technologies offer products having a broad range of conductivity, excellent transparency, neutral color tone, good adhesion, abrasion resistance as well as mechanical robustness. Additional benefits include ease of ambient processing and patterning capability. This paper reports our recent findings on achieving 2.6% and 1.4% efficiencies on nonoptimized organic photovoltaic cells employing SWNT as a transparent electrode.

  14. Resonance Raman Spectroscopy of Armchair Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Haroz, Erik; Rice, William; Lu, Benjamin; Hauge, Robert; Magana, Donny; Doorn, Stephen; Nikolaev, Pasha; Arepalli, Sivaram; Kono, Junichiro

    2009-03-01

    We performed resonance Raman spectroscopy studies of metallic single-walled carbon nanotubes (SWNTs), including armchair SWNTs from (6,6) through (10,10). The measurements were carried out with excitation of 440-850 nm on aqueous ensemble samples of SWNTs enriched in metallic species. From this, we generated Raman excitation profiles (REPs) of the radial breathing mode and compare the REPs of armchairs and other metallic species. Additionally, we measured REPs of the G-band mode and observed how the Breit-Wigner-Fano line shape of the G^- peak evolves in peak position, width and intensity relative to the G^+ peak as different metallic nanotubes are excited. By combining these studies with absorption and photoluminescence excitation spectroscopy studies, we present a comprehensive examination of the optical signatures of metallic SWNTs.

  15. Generalizing thermodynamic properties of bulk single-walled carbon nanotubes

    PubMed Central

    Rodriguez, Kenneth R.; Nanney, Warren A.; A. Maddux, Cassandra J.; Martínez, Hernán L.

    2014-01-01

    The enthalpy and Gibbs free energy thermodynamical potentials of single walled carbon nanotubes were studied of all types (armchairs, zig-zags, chirals (n>m), and chiral (n

  16. Generalizing thermodynamic properties of bulk single-walled carbon nanotubes

    SciTech Connect

    Rodriguez, Kenneth R. Nanney, Warren A.; Maddux, Cassandra J.A.; Martínez, Hernán L.; Malone, Marvin A.; Coe, James V.

    2014-12-15

    The enthalpy and Gibbs free energy thermodynamical potentials of single walled carbon nanotubes were studied of all types (armchairs, zig-zags, chirals (n>m), and chiral (n

  17. Generalizing thermodynamic properties of bulk single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Rodriguez, Kenneth R.; Malone, Marvin A.; Nanney, Warren A.; A. Maddux, Cassandra J.; Coe, James V.; Martínez, Hernán L.

    2014-12-01

    The enthalpy and Gibbs free energy thermodynamical potentials of single walled carbon nanotubes were studied of all types (armchairs, zig-zags, chirals (n>m), and chiral (n

  18. Finely dispersed single-walled carbon nanotubes for polysaccharide hydrogels.

    PubMed

    Yan, Liang Yu; Chen, Hailan; Li, Peng; Kim, Dong-Hwan; Chan-Park, Mary B

    2012-09-26

    Here we demonstrate a polysaccharide hydrogel reinforced with finely dispersed single-walled carbon nanotubes (SWNTs) using biocompatible dispersants O-carboxymethylchitosan (OC) and chondroitin sulfate A (CS-A) as a structural support. Both of the dispersants can disperse SWNTs in aqueous solutions and hydrogel matrix as individual tubes or small bundles. Additionally, we have found that compressive modulus and strain of the hydrogels reinforced with SWNTs were enhanced as much as two times by the addition of a few weight percent of SWNTs. Moreover, the SWNT-incorporated hydrogels exhibited lower impedance and higher charge capacity than the alginate/dispersant hydrogel without SWNTs. The OC and the CS-A demonstrated much higher reinforcing enhancement than a commercially available dispersant, sodium dodecyl sulfate. Combined with the experimental data on the mechanical and electrical properties, the biocompatibility of OC and CS-A can provide the possibility of biomedical application of the SWNT-reinforced hydrogels. PMID:22909447

  19. Charge-induced strains in single-walled carbon nanotubes.

    PubMed

    Li, Chun-Yu; Chou, Tsu-Wei

    2006-09-28

    This paper investigates the electromechanical coupling in single-walled carbon nanotubes. In the model system, the extra electric charge of the nanotube is assumed to be uniformly distributed on carbon atoms. The electrostatic interactions between charged carbon atoms are calculated using the Coulomb law. The deformation of the charged nanotube is obtained by using the molecular structural mechanics method and considering the electrostatic interactions as an external loading acting on carbon atoms. The axial strain is found to be a symmetric function of applied charge, and our predictions are in very good agreement with those from ab initio calculations. The present results indicate that the nanotube aspect ratio has a strong effect on the axial strain when the ratio is less than 10 and the general trend is that the strain increases with the aspect ratio. The peak axial and radial strains occur at nanotube diameters of around 1.2-1.5 nm. PMID:21727586

  20. Single Wall Carbon Nanotube-polymer Solar Cells

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Castro, Stephanie L.; Landi, Brian J.; Gennett, Thomas; Raffaelle, Ryne P.

    2005-01-01

    Investigation of single wall carbon nanotube (SWNT)-polymer solar cells has been conducted towards developing alternative lightweight, flexible devices for space power applications. Photovoltaic devices were constructed with regioregular poly(3-octylthiophene)-(P3OT) and purified, >95% w/w, laser-generated SWNTs. The P3OT composites were deposited on ITO-coated polyethylene terapthalate (PET) and I-V characterization was performed under simulated AM0 illumination. Fabricated devices for the 1.0% w/w SWNT-P3OT composites showed a photoresponse with an open-circuit voltage (V(sub oc)) of 0.98 V and a short-circuit current density (I(sub sc)) of 0.12 mA/sq cm. Optimization of carrier transport within these novel photovoltaic systems is proposed, specifically development of nanostructure-SWNT complexes to enhance exciton dissociation.

  1. Fluorescent single walled nanotube/silica composite materials

    DOEpatents

    Dattelbaum, Andrew M.; Gupta, Gautam; Duque, Juan G.; Doorn, Stephen K.; Hamilton, Christopher E.; DeFriend Obrey, Kimberly A.

    2013-03-12

    Fluorescent composites of surfactant-wrapped single-walled carbon nanotubes (SWNTs) were prepared by exposing suspensions of surfactant-wrapped carbon nanotubes to tetramethylorthosilicate (TMOS) vapor. Sodium deoxycholate (DOC) and sodium dodecylsulphate (SDS) were the surfactants. No loss in emission intensity was observed when the suspension of DOC-wrapped SWNTs were exposed to the TMOS vapors, but about a 50% decrease in the emission signal was observed from the SDS-wrapped SWNTs nanotubes. The decrease in emission was minimal by buffering the SDS/SWNT suspension prior to forming the composite. Fluorescent xerogels were prepared by adding glycerol to the SWNT suspensions prior to TMOS vapor exposure, followed by drying the gels. Fluorescent aerogels were prepared by replacing water in the gels with methanol and then exposing them to supercritical fluid drying conditions. The aerogels can be used for gas sensing.

  2. Characterization of single-walled carbon nanotubes for environmental implications

    USGS Publications Warehouse

    Agnihotri, S.; Rostam-Abadi, M.; Rood, M.J.

    2004-01-01

    Adsorption capacities of N2 and various organic vapors (methyl-ethyl ketone (MEK), toluene, and cyclohexane) on select electric-arc and HiPco produced single walled carbon nanotubes (SWNT) were measured at 77 and 298 K, respectively. The amount of N2 adsorbed on a SWNT sample depended on the sample purity, methodology, and on the sample age. Adsorption capacities of organic vapors (100-1000 ppm vol) on SWNT in humid conditions were much higher than those for microporous activated carbons. These results established a foundation for additional studies related to potential environmental applications of SWNT. The MEK adsorption capacities of samples EA95 and CVD80 and mesoporous tire-derived activated carbon in humid conditions were lower than in dry conditions. This is an abstract of a paper presented at the AIChE Annual Meeting (Austin, TX 11/7-12/2004).

  3. General synthesis of inorganic single-walled nanotubes

    NASA Astrophysics Data System (ADS)

    Ni, Bing; Liu, Huiling; Wang, Peng-Peng; He, Jie; Wang, Xun

    2015-10-01

    The single-walled nanotube (SWNT) is an interesting nanostructure for fundamental research and potential applications. However, very few inorganic SWNTs are available to date due to the lack of efficient fabrication methods. Here we synthesize four types of SWNT: sulfide; hydroxide; phosphate; and polyoxometalate. Each type of SWNT possesses essentially uniform diameters. Detailed studies illustrate that the formation of SWNTs is initiated by the self-coiling of the corresponding ultrathin nanostructure embryo/building blocks on the base of weak interactions between them, which is not limited to specific compounds or crystal structures. The interactions between building blocks can be modulated by varying the solvents used, thus multi-walled tubes can also be obtained. Our results reveal that the generalized synthesis of inorganic SWNTs can be achieved by the self-coiling of ultrathin building blocks under the proper weak interactions.

  4. General synthesis of inorganic single-walled nanotubes.

    PubMed

    Ni, Bing; Liu, Huiling; Wang, Peng-peng; He, Jie; Wang, Xun

    2015-01-01

    The single-walled nanotube (SWNT) is an interesting nanostructure for fundamental research and potential applications. However, very few inorganic SWNTs are available to date due to the lack of efficient fabrication methods. Here we synthesize four types of SWNT: sulfide; hydroxide; phosphate; and polyoxometalate. Each type of SWNT possesses essentially uniform diameters. Detailed studies illustrate that the formation of SWNTs is initiated by the self-coiling of the corresponding ultrathin nanostructure embryo/building blocks on the base of weak interactions between them, which is not limited to specific compounds or crystal structures. The interactions between building blocks can be modulated by varying the solvents used, thus multi-walled tubes can also be obtained. Our results reveal that the generalized synthesis of inorganic SWNTs can be achieved by the self-coiling of ultrathin building blocks under the proper weak interactions. PMID:26510862

  5. Single Wall Carbon Nanotube-Based Structural Health Sensing Materials

    NASA Technical Reports Server (NTRS)

    Watkins, A. Neal; Ingram, JoAnne L.; Jordan, Jeffrey D.; Wincheski, Russell A.; Smits, Jan M.; Williams, Phillip A.

    2004-01-01

    Single wall carbon nanotube (SWCNT)-based materials represent the future aerospace vehicle construction material of choice based primarily on predicted strength-to-weight advantages and inherent multifunctionality. The multifunctionality of SWCNTs arises from the ability of the nanotubes to be either metallic or semi-conducting based on their chirality. Furthermore, simply changing the environment around a SWCNT can change its conducting behavior. This phenomenon is being exploited to create sensors capable of measuring several parameters related to vehicle structural health (i.e. strain, pressure, temperature, etc.) The structural health monitor is constructed using conventional electron-beam lithographic and photolithographic techniques to place specific electrode patterns on a surface. SWCNTs are then deposited between the electrodes using a dielectrophoretic alignment technique. Prototypes have been constructed on both silicon and polyimide substrates, demonstrating that surface-mountable and multifunctional devices based on SWCNTs can be realized.

  6. Shaping single walled nanotubes with an electron beam

    SciTech Connect

    Zobelli, A.; Gloter, A.; Colliex, C.; Ewels, C. P.

    2008-01-15

    We show that electron irradiation in a dedicated scanning transmission microscope can be used as a nano-electron-lithography technique allowing the controlled reshaping of single walled carbon and boron nitride nanotubes. The required irradiation conditions have been optimized on the basis of total knock-on cross sections calculated within density functional based methods. It is then possible to induce morphological modifications, such as a local change of the tube chirality, by sequentially removing several tens of atoms with a nanometrical spatial resolution. We show that electron beam heating effects are limited. Thus, electron beam induced vacancy migration and nucleation might be excluded. These irradiation techniques could open new opportunities for nanoengineering a large variety of nanostructured materials.

  7. Selective bundling of zigzag single-walled carbon nanotubes.

    PubMed

    Blum, Carolin; Stürzl, Ninette; Hennrich, Frank; Lebedkin, Sergei; Heeg, Sebastian; Dumlich, Heiko; Reich, Stephanie; Kappes, Manfred M

    2011-04-26

    A simple, high throughput fractionation procedure for aqueous/SDS (sodium dodecyl sulfate) suspensions of single-walled carbon nanotubes (SWNTs) is presented, which yields thin bundles of semiconducting-SWNTs with small chiral angles. To demonstrate this we show the photoluminescence signatures of nanotube suspensions that contain almost exclusively zigzag and near-zigzag tubes. Starting suspensions and resulting fractions were characterized using optical absorption, resonance Raman and photoluminescence spectroscopies as well as scanning force microscopy. Taken together with literature observations, our findings suggest that near zigzag edge tubes of similar diameters in a bundle are harder to separate from each other than for other chiral index combinations. We discuss the implications of these observations for SWNT growth and dispersion. PMID:21410134

  8. Extracellular entrapment and degradation of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Farrera, Consol; Bhattacharya, Kunal; Lazzaretto, Beatrice; Andón, Fernando T.; Hultenby, Kjell; Kotchey, Gregg P.; Star, Alexander; Fadeel, Bengt

    2014-05-01

    Neutrophils extrude neutrophil extracellular traps (NETs) consisting of a network of chromatin decorated with antimicrobial proteins to enable non-phagocytic killing of microorganisms. Here, utilizing a model of ex vivo activated human neutrophils, we present evidence of entrapment and degradation of carboxylated single-walled carbon nanotubes (SWCNTs) in NETs. The degradation of SWCNTs was catalyzed by myeloperoxidase (MPO) present in purified NETs and the reaction was facilitated by the addition of H2O2 and NaBr. These results show that SWCNTs can undergo acellular, MPO-mediated biodegradation and imply that the immune system may deploy similar strategies to rid the body of offending microorganisms and engineered nanomaterials.Neutrophils extrude neutrophil extracellular traps (NETs) consisting of a network of chromatin decorated with antimicrobial proteins to enable non-phagocytic killing of microorganisms. Here, utilizing a model of ex vivo activated human neutrophils, we present evidence of entrapment and degradation of carboxylated single-walled carbon nanotubes (SWCNTs) in NETs. The degradation of SWCNTs was catalyzed by myeloperoxidase (MPO) present in purified NETs and the reaction was facilitated by the addition of H2O2 and NaBr. These results show that SWCNTs can undergo acellular, MPO-mediated biodegradation and imply that the immune system may deploy similar strategies to rid the body of offending microorganisms and engineered nanomaterials. Electronic supplementary information (ESI) available: Suppl. Fig. 1 - length distribution of SWCNTs; suppl. Fig. 2 - characterization of pristine vs. oxidized SWCNTs; suppl. Fig. 3 - endotoxin evaluation; suppl. Fig. 4 - NET characterization; suppl. Fig. 5 - UV-Vis/NIR analysis of biodegradation of oxidized SWCNTs; suppl. Fig. 6 - cytotoxicity of partially degraded SWCNTs. See DOI: 10.1039/c3nr06047k

  9. Single wall carbon nanotubes: Separation and applications to biosensors

    NASA Astrophysics Data System (ADS)

    Kim, Sang Nyon

    Single wall carbon nanotubes uniquely exhibit one-dimensional quantum confined properties by being either semiconducting (sem-) or metallic (met-) depending on their atomic arrangements. The stochastic nature of SWNT growth renders met-:sem- ratio being 1:2 and diameter range being distributed in 0.4-2nm with a close-packed bundle configuration. For many high-performance devices using SWNTs, acquiring well-separated and/or isolated single-diameter, metallicity and/or chirality nanotubes is greatly in demand. Recently, the bulk separation and/or enrichment of single wall carbon nanotubes (SWNTs) according to type (or otherwise termed "metallicity") and diameter (dt) has become possible. This thesis presents a route to probe mechanisms in diameter and metallicity dependent separation of SWNTs. A systematic analysis tool, that enables the quantitative examination of resonance Raman spectra, is established from nanotube samples that have been separated according to metallicity and d t via an octadecylamine mediated protocol. This protocol uses the relative changes in the integrated intensities of the radial-breathing mode region for the quantitative evaluation. By further establishing the physicochemical properties of charge-stabilized SWNT dispersions in polar aprotic media (i.e. N,N-dimethylformide) a more detailed description of the underlying separation mechanism is given. Here, I use resonance Raman spectroscopy (RRS) as a tool to probe SWNT redox chemistry. The Gibbs free energy, modeled by calculating the charge-loss from the (n,m)-dependent integrated density of states across the corresponding jump in the redox potential, is utilized to support the separation mechanism. Additionally, the evaluation of SWNT forest platforms for amperometric protein immunoassays is presented. Horseradish peroxidase is used as the label and the sensing signals are acquired from electrochemical reduction of hydrogen peroxide. Specific studies on human serum albumin and prostate

  10. Center for Applications of Single-Walled Carbon Nanotubes

    SciTech Connect

    Resasco, Daniel E

    2008-02-21

    This report describes the activities conducted under a Congressional Direction project whose goal was to develop applications for Single-walled carbon nanotubes, under the Carbon Nanotube Technology Center (CANTEC), a multi-investigator program that capitalizes on OU’s advantageous position of having available high quality carbon nanotubes. During the first phase of CANTEC, 11 faculty members and their students from the College of Engineering developed applications for carbon nanotubes by applying their expertise in a number of areas: Catalysis, Reaction Engineering, Nanotube synthesis, Surfactants, Colloid Chemistry, Polymer Chemistry, Spectroscopy, Tissue Engineering, Biosensors, Biochemical Engineering, Cell Biology, Thermal Transport, Composite Materials, Protein synthesis and purification, Molecular Modeling, Computational Simulations. In particular, during this phase, the different research groups involved in CANTEC made advances in the tailoring of Single-Walled Carbon Nanotubes (SWNT) of controlled diameter and chirality by Modifying Reaction Conditions and the Nature of the catalyst; developed kinetic models that quantitatively describe the SWNT growth, created vertically oriented forests of SWNT by varying the density of metal nanoparticles catalyst particles, and developed novel nanostructured SWNT towers that exhibit superhydrophobic behavior. They also developed molecular simulations of the growth of Metal Nanoparticles on the surface of SWNT, which may have applications in the field of fuell cells. In the area of biomedical applications, CANTEC researchers fabricated SWNT Biosensors by a novel electrostatic layer-by-layer (LBL) deposition method, which may have an impact in the control of diabetes. They also functionalized SWNT with proteins that retained the protein’s biological activity and also retained the near-infrared light absorbance, which finds applications in the treatment of cancer.

  11. Uptake of poly-dispersed single-walled carbon nanotubes and decline of functions in mouse NK cells undergoing activation.

    PubMed

    Alam, Anwar; Puri, Niti; Saxena, Rajiv K

    2016-09-01

    The interaction of poly-dispersed acid-functionalized single-walled carbon nanotubes (AF-SWCNT) with NK cells undergoing activation was examined. Exposure to AF-SWCNT during NK activation in vitro by interleukin (IL)-2, and in vivo by Poly(I:C) significantly lowered cytotoxic activity generated against YAC-1 tumor cells. Recoveries of spleen NK1.1(+) cells as well as the activated subset of NK cells (NK1.1(+)CD69(+) cells) were significantly reduced by the AF-SWCNT exposure. The proportion of apoptotic NK cells (NK1.1(+) phosphatidylserine(+)) in the spleen cell preparations activated in vitro was also significantly elevated. Expression levels of CD107a [for assessing NK cell degranulation] as well as of FasL marker [mediating non-secretory pathway of NK cell killing] were significantly lower in cells exposed to AF-SWCNT during the activation phase. Intracellular levels of interferon (IFN)-γ and tumor necrosis factor (TNF)-α in the cells were also significantly reduced. Fluorescent AF-SWCNT (FAF-SWCNT) were internalized by the NK cells and uptake was significantly greater in activated cells. Confocal microscopy indicated the internalized FAF-SWCNT were localized to the cytoplasm of the NK cells. These results indicated that AF-SWCNT were internalized by NK cells and caused a general down-regulation of a variety of parameters associated with NK cell cytotoxicity and other cellular functions. PMID:27416475

  12. Electrochemical Redox Switchable Dispersion of Single-Walled Carbon Nanotubes in Water.

    PubMed

    Feng, Anchao; Peng, Liao; Liu, Bowen; Liu, Senyang; Wang, Shanfeng; Yuan, Jinying

    2016-05-01

    We present a new, efficient approach to achieve superior dispersibility of single-walled carbon nanotubes (SWNTs) in water by integrating reversible host-guest interaction and π-π stacking. In this approach, β-cyclodextrin (β-CD) was first modified with a pyrene group to be adsorbed onto the wall of pristine SWNTs via π-π stacking, followed by further functionalization with ferrocene (Fc)-terminated water-soluble poly(ethylene glycol) (PEG) through supramolecular host-guest interaction between β-CD and Fc. Upon alternate electrochemical oxidative/reductive stimuli, the reversible host-guest pair enabled the PEG-Fc@Py-CD@SWNTs to exhibit switchable conversion between dispersion and aggregation states. Electric field controllable PEG-Fc@Py-CD@SWNTs with good reversibility and intact nanotube structure may find potential applications in selective screening of SWNTs, biosensors, and targeted drug delivery. PMID:27025460

  13. Directed Assembly of Single Wall Carbon Nanotube Field Effect Transistors.

    PubMed

    Penzo, Erika; Palma, Matteo; Chenet, Daniel A; Ao, Geyou; Zheng, Ming; Hone, James C; Wind, Shalom J

    2016-02-23

    The outstanding electronic properties of single wall carbon nanotubes (SWCNTs) have made them prime candidates for future nanoelectronics technologies. One of the main obstacles to the implementation of advanced SWCNT electronics to date is the inability to arrange them in a manner suitable for complex circuits. Directed assembly of SWCNT segments onto lithographically patterned and chemically functionalized substrates is a promising way to organize SWCNTs in topologies that are amenable to integration for advanced applications, but the placement and orientational control required have not yet been demonstrated. We have developed a technique for assembling length sorted and chirality monodisperse DNA-wrapped SWCNT segments on hydrophilic lines patterned on a passivated oxidized silicon substrate. Placement of individual SWCNT segments at predetermined locations was achieved with nanometer accuracy. Three terminal electronic devices, consisting of a single SWCNT segment placed either beneath or on top of metallic source/drain electrodes were fabricated. Devices made with semiconducting nanotubes behaved as typical p-type field effect transistors (FETs), whereas devices made with metallic nanotubes had a finite resistance with little or no gate modulation. This scalable, high resolution approach represents an important step forward toward the potential implementation of complex SWCNT devices and circuits. PMID:26807948

  14. Fabrication of stretchable single-walled carbon nanotube logic devices.

    PubMed

    Yoon, Jangyeol; Shin, Gunchul; Kim, Joonsung; Moon, Young Sun; Lee, Seung-Jung; Zi, Goangseup; Ha, Jeong Sook

    2014-07-23

    The fabrication of a stretchable single-walled carbon nanotube (SWCNT) complementary metal oxide semiconductor (CMOS) inverter array and ring oscillators is reported. The SWCNT CMOS inverter exhibits static voltage transfer characteristics with a maximum gain of 8.9 at a supply voltage of 5 V. The fabricated devices show stable electrical performance under the maximum strain of 30% via forming wavy configurations. In addition, the 3-stage ring oscillator demonstrates a stable oscillator frequency of ∼3.5 kHz at a supply voltage of 10 V and the oscillating waveforms are maintained without any distortion under cycles of pre-strain and release. The strains applied to the device upon deformation are also analyzed by using the classical lamination theory, estimating the local strain of less than 0.6% in the SWCNT channel and Pd electrode regions which is small enough to keep the device performance stable under the pre-strain up to 30%. This work demonstrates the potential application of stretchable SWCNT logic circuit devices in future wearable electronics. PMID:24700788

  15. Sorting centimetre-long single-walled carbon nanotubes.

    PubMed

    Yu, Woo Jong; Chae, Sang Hoon; Vu, Quoc An; Lee, Young Hee

    2016-01-01

    While several approaches have been developed for sorting metallic (m) or semiconducting (s) single-walled carbon nanotubes (SWCNTs), the length of SWCNTs is limited within a micrometer, which restricts excellent electrical performances of SWCNTs for macro-scale applications. Here, we demonstrate a simple sorting method of centimetre-long aligned m- and s-SWCNTs. Ni particles were selectively and uniformly coated along the 1-cm-long m-SWCNTs by applying positive gate bias during electrochemical deposition with continuous electrolyte injection. To sort s-SWCNTs, the Ni coating was oxidized to form insulator outer for blocking of current flow through inner m-SWCNTs. Sorting of m-SWCNTs were demonstrated by selective etching of s-SWCNTs via oxygen plasma, while the protected m-SWCNTs by Ni coating remained intact. The series of source-drain pairs were patterned along the 1-cm-long sorted SWCNTs, which confirmed high on/off ratio of 10(4)-10(8) for s-SWCNTs and nearly 1 for m-SWCNTs. PMID:27476909

  16. Coarse-grained potentials of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhao, Junhua; Jiang, Jin-Wu; Wang, Lifeng; Guo, Wanlin; Rabczuk, Timon

    2014-11-01

    We develop the coarse-grained (CG) potentials of single-walled carbon nanotubes (SWCNTs) in CNT bundles and buckypaper for the study of the static and dynamic behaviors. The explicit expressions of the CG stretching, bending and torsion potentials for the nanotubes are obtained by the stick-spiral and the beam models, respectively. The non-bonded CG potentials between two different CG beads are derived from analytical results based on the cohesive energy between two parallel and crossing SWCNTs from the van der Waals interactions. We show that the CG model is applicable to large deformations of complex CNT systems by combining the bonded potentials with non-bonded potentials. Checking against full atom molecular dynamics calculations and our analytical results shows that the present CG potentials have high accuracy. The established CG potentials are used to study the mechanical properties of the CNT bundles and buckypaper efficiently at minor computational cost, which shows great potential for the design of micro- and nanomechanical devices and systems.

  17. Reinforced thermoplastic polyimide with dispersed functionalized single wall carbon nanotubes.

    PubMed

    Lebrón-Colón, Marisabel; Meador, Michael A; Gaier, James R; Solá, Francisco; Scheiman, Daniel A; McCorkle, Linda S

    2010-03-01

    Molecular pi-complexes were formed from pristine HiPCO single- wall carbon nanotubes (SWCNTs) and 1-pyrene- N-(4-N'-(5-norbornene-2,3-dicarboxyimido)phenyl butanamide, 1. Polyimide films were prepared with these complexes as well as uncomplexed SWCNTs and the effects of nanoadditive addition on mechanical, thermal, and electrical properties of these films were evaluated. Although these properties were enhanced by both nanoadditives, larger increases in tensile strength and thermal and electrical conductivities were obtained when the SWCNT/1 complexes were used. At a loading level of 5.5 wt %, the T(g) of the polyimide increased from 169 to 197 degrees C and the storage modulus increased 20-fold (from 142 to 3045 MPa). The addition of 3.5 wt % SWCNT/1 complexes increased the tensile strength of the polyimide from 61.4 to 129 MPa; higher loading levels led to embrittlement and lower tensile strengths. The electrical conductivities (DC surface) of the polyimides increased to 1 x 10(-4) Scm(-1) (SWCNT/1 complexes loading level of 9 wt %). Details of the preparation of these complexes and their effects on polyimide film properties are discussed. PMID:20356267

  18. Single-walled carbon nanotube based molecular switch tunnel junctions.

    PubMed

    Diehl, Michael R; Steuerman, David W; Tseng, Hsian-Rong; Vignon, Scott A; Star, Alexander; Celestre, Paul C; Stoddart, J Fraser; Heath, James R

    2003-12-15

    This article describes two-terminal molecular switch tunnel junctions (MSTJs) which incorporate a semiconducting, single-walled carbon nanotube (SWNT) as the bottom electrode. The nanotube interacts noncovalently with a monolayer of bistable, nondegenerate [2]catenane tetracations, self-organized by their supporting amphiphilic dimyristoylphosphatidyl anions which shield the mechanically switchable tetracations from a two-micrometer wide metallic top electrode. The resulting 0.002 micron 2 area tunnel junction addresses a nanometer wide row of approximately 2000 molecules. Active and remnant current-voltage measurements demonstrated that these devices can be reconfigurably switched and repeatedly cycled between high and low current states under ambient conditions. Control compounds, including a degenerate [2]catenane, were explored in support of the mechanical origin of the switching signature. These SWNT-based MSTJs operate like previously reported silicon-based MSTJs, but differently from similar devices incorporating bottom metal electrodes. The relevance of these results with respect to the choice of electrode materials for molecular electronics devices is discussed. PMID:14714382

  19. Methane storage on aluminum-doped single wall BNNTs

    NASA Astrophysics Data System (ADS)

    Azizi, Khaled; Salabat, Kobra; Seif, Abdolvahab

    2014-08-01

    Adsorption of methane (CH4) on inside and outside of aluminum-doped (Al-doped) zigzag single-walled boron nitride nanotubes, BNNTs/Al, has been studied using density-functional theory (DFT) method. The effect of diameter and type of atom of BNNT replaced by the Al atom on the adsorption properties of CH4 were investigated. Our results indicate that, compared to pristine BNNTs, replacing both B atom by Al, BNNT/Al(B) and N atom by Al, BNNT/Al(N), can notably enhance the binding energy of CH4 on BNNTs and the latter case has been more superior. The average binding energy for the most stable configuration of CH4 on BNNTs/Al(N) and BNNTs/Al(B) are about -26.12 and -16.53 kJ mol-1, respectively, which are typical for the physisorption and suitable for technical applications. The results show that while the geometry of BNNT/Al(N or B)-CH4 complexes is determined by weak electrostatic forces, the binding energy mainly determines by dispersion forces. For all complexes, the energy gaps, natural bond orbital (NBO) analysis, dipole moments, natural charge and density of state (DOS) diagrams were extracted. Finally, the applicability of BNNTs/Al(N) both as a medium for storage and gas sensor for methane detection were confirmed.

  20. Resonance Raman Optical Activity of Single Walled Chiral Carbon Nanotubes.

    PubMed

    Nagy, Péter R; Koltai, János; Surján, Péter R; Kürti, Jenő; Szabados, Ágnes

    2016-07-21

    Resonance (vibrational) Raman Optical Activity (ROA) spectra of six chiral single-walled carbon nanotubes (SWCNTs) are studied by theoretical means. Calculations are performed imposing line group symmetry. Polarizability tensors, computed at the π-electron level, are differentiated with respect to DFT normal modes to generate spectral intensities. This computational protocol yields a ROA spectrum in good agreement with the only experiment on SWCNT, available at present. In addition to the conventional periodic electric dipole operator we introduce magnetic dipole and electric quadrupole operators, suitable for conventional k-space calculations. Consequences of the complex nature of the wave function on the scattering cross section are discussed in detail. The resonance phenomenon is accounted for by the short time approximation. Involvement of fundamental vibrations in the region of the intermediate frequency modes is found to be more notable in ROA than in Raman spectra. Calculations indicate exceptionally strong resonance enhancement of SWCNT ROA signals. Resonance ROA profile of the (6,5) tube shows an interesting sign change that may be exploited experimentally for SWCNT identification. PMID:27315548

  1. MINIMAL INFLAMMOGENICITY OF PRISTINE SINGLE-WALL CARBON NANOTUBES

    PubMed Central

    TOYOKUNI, SHINYA; JIANG, LI; KITAURA, RYO; SHINOHARA, HISANORI

    2015-01-01

    ABSTRACT Carbon nanotubes (CNTs) are a novel synthetic material comprising only carbon atoms. Based on its rigidity, its electrical and heat conductivity and its applicability to surface manufacturing, this material is expected to have numerous applications in industry. However, due to the material’s dimensional similarity to asbestos fibers, its carcinogenicity was hypothesized during the last decade, and indeed, we have shown that multi-wall CNTs (MWCNTs) of 50 nm in diameter are potently carcinogenic to mesothelial cells after intraperitoneal injection. Additionally, we suggested that inflammogenicity after intraperitoneal injection can predict mesothelial carcinogenesis. However, few data have been published on the intraperitoneal inflammogenicity of single-wall CNTs (SWCNTs). Here, we conducted a series of studies on SWCNTs using both intraperitoneal injection into rats and MeT5A mesothelial cells. Intraperitoneal injection of 10 mg SWCNTs caused no remarkable inflammation in the abdominal cavity, and the exposure of MeT5A cells to up to 25 μg/cm2 SWCNTs did not alter proliferation. MWCNTs of 50 nm in diameter were used as a positive control, and tangled MWCNTs of 15 nm in diameter were used as a negative control. The results suggest that SWCNTs are a low-risk material with respect to mesothelial carcinogenesis. PMID:25797984

  2. Potassium-Decorated, Single-Wall Carbon Nanotubes.

    NASA Astrophysics Data System (ADS)

    Rao, A. M.; Richter, E.; Menon, M.; Subbaswamy, K. R.; Eklund, P. C.; Thess, A.; Smalley, R. E.

    1997-03-01

    Crystalline ropes of single-wall carbon nanotubes have been reacted in sealed glass tubes with potassium vapor and Raman scattering has been used to monitor the vibrational modes as a function of reaction time. An overall broadening and downshifting of the Raman bands is observed. For example, huge downshifts (40 cm-1) in the high frequency tangential modes observed near 1593 cm-1 in the pristine tubes are detected. These downshifts are attributed to significant charge transfer of K 4s electrons into antibonding pz states of the nanotube which should expand the tube diameter and soften the lattice. Presumably, the potassium ions are chemisorbed onto the walls of the nanotubes, rather than inside the nanotube, although no structural information to support this model has yet been collected. Theoretical results on electron doped armchair symmetry nanotubes using the Generalized Tight Binding Molecular Dynamics model will also be presented to help explain experimental results. The Kentucky group was supported by the University of Kentucky Center for Applied Energy Research and NSF Grant No. OSR-94-52895 and DOE Contract No. DE-F22-90PC90029. The work at Rice was supported by the Office of Naval Research Contract N0014-91-J1794.

  3. Third Harmonic Generation from Aligned Single-Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Morris, Darius T., Jr.

    Optical properties of single-wall carbon nanotubes (SWCNTs) have been extensively studied during the last decade, and much basic knowledge has been accumulated on how light emission, scattering, and absorption occur in the realm of linear optics. However, their nonlinear optical properties remain largely unexplored. Here, we have observed strong third harmonic generation from highly aligned SWCNTs with intense mid-infrared radiation. Through power dependent experiments, we have determined the absolute value of the third-order nonlinear optical susceptibility, chi(3), of our SWCNT film to be 6.92 x 10--12 esu, which is three orders of magnitude larger than that of the fused silica reference sample we used. Furthermore, through polarization-dependent third harmonic generation experiments, all the nonzero tensor elements of chi(3) have also been extracted. The contribution of the weaker tensor elements to the overall chi (3) signal has been calculated to be approximately 1/6 of that of the dominant c3z zzz component. These results open up new possibilities for application of carbon nanotubes in optoelectronics.

  4. Single-wall carbon nanotube chemical attachment at platinum electrodes

    NASA Astrophysics Data System (ADS)

    Rosario-Castro, Belinda I.; Contés-de-Jesús, Enid J.; Lebrón-Colón, Marisabel; Meador, Michael A.; Scibioh, M. Aulice; Cabrera, Carlos R.

    2010-11-01

    Self-assembled monolayer (SAM) techniques were used to adsorb 4-aminothiophenol (4-ATP) on platinum electrodes in order to obtain an amino-terminated SAM as the base for the chemical attachment of single-wall carbon nanotubes (SWCNTs). A physico-chemical, morphological and electrochemical characterizations of SWCNTs attached onto the modified Pt electrodes was done by using reflection-absorption infrared spectroscopy (RAIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and cyclic voltammetry (CV) techniques. The SWNTs/4-ATP/Pt surface had regions of small, medium, and large thickness of carbon nanotubes with heights of 100-200 nm, 700 nm to 1.5 μm, and 1.0-3.0 μm, respectively. Cyclic voltammetries (CVs) in sulfuric acid demonstrated that attachment of SWNTs on 4-ATP/Pt is markedly stable, even after 30 potential cycles. CV in ruthenium hexamine was similar to bare Pt electrodes, suggesting that SWNTs assembly is similar to a closely packed microelectrode array.

  5. Single-wall carbon nanotubes and peapods investigated by EPR.

    PubMed

    Corzilius, B; Dinse, K-P; Hata, K

    2007-12-14

    Single-wall carbon nanotubes (SWNT) prepared by the "super growth" method developed recently exhibit electron paramagnetic resonance (EPR) signals, which can be attributed to itinerant spins. EPR results indicate very low defect and catalyst concentrations in this superior material. Under these conditions EPR can be used to study details of charge transport properties over a wide temperature range, although the material is still very "heterogeneous" with respect to tube diameter and chirality. Non-resonant microwave absorption in the temperature range below 20 K is indicative for the opening of a small gap at the Fermi energy for tubes of metallic character, which is indicative for a transition into a superconducting state. Using SWNT filled partially with an endohedral spin probe like N@C(60), such "peapods" can be investigated "from the inside". Continuous-wave (cw) and pulsed EPR was used to investigate localization dynamics within the tubes or to check for interaction with itinerant electrons. Using SWNT grown by different methods, the dominant influence of tube diameter on fullerene dynamics was revealed by temperature dependent pulsed EPR experiments. These differences can be correlated with the interactions between the endohedral observer spin and spins on the SWNT. PMID:18167581

  6. Low-temperature growth of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kim, S.-M.; Zhang, Y.; Wang, X.; Teo, K. B. K.; Gangloff, L.; Milne, W. I.; Wu, J.; Eastman, M.; Jiao, J.

    2007-12-01

    The low-temperature synthesis (450-560 °C) of single-walled carbon nanotubes (SWCNTs) on a triple-layered catalyst, Al/Fe/Mo, was performed using aromatic hydrocarbon radicals which were produced from the pyrolysis of C2H2. Two approaches were used; in the first, these hydrocarbon radicals were produced using a high-temperature heater (830 °C), but the substrate where the SWCNTs were grown was placed on a thermal insulator above it such that the substrate was at a much lower temperature. In the second approach, a heated nozzle system operating at 830 °C was used to introduce the hydrocarbon radicals onto the substrate which was located a few centimetres below it. Both these approaches rely on the thermal dissociation and recombination of C2H2 for the formation of complex high-order radicals, i.e. C6H9, C5H9, C6H13, whose presence was confirmed by in situ mass spectroscopy. The density of SWCNTs deposited could be correlated directly with the concentration of these precursors.

  7. Single walled carbon nanotube composites for bone tissue engineering.

    PubMed

    Gupta, Ashim; Woods, Mia D; Illingworth, Kenneth David; Niemeier, Ryan; Schafer, Isaac; Cady, Craig; Filip, Peter; El-Amin, Saadiq F

    2013-09-01

    The purpose of this study was to develop single walled carbon nanotubes (SWCNT) and poly lactic-co-glycolic acid (PLAGA) composites for orthopedic applications and to evaluate the interaction of human stem cells (hBMSCs) and osteoblasts (MC3T3-E1 cells) via cell growth, proliferation, gene expression, extracellular matrix production and mineralization. PLAGA and SWCNT/PLAGA composites were fabricated with various amounts of SWCNT (5, 10, 20, 40, and 100 mg), characterized and degradation studies were performed. Cells were seeded and cell adhesion/morphology, growth/survival, proliferation and gene expression analysis were performed to evaluate biocompatibility. Imaging studies demonstrated uniform incorporation of SWCNT into the PLAGA matrix and addition of SWCNT did not affect the degradation rate. Imaging studies revealed that MC3T3-E1 and hBMSCs cells exhibited normal, non-stressed morphology on the composites and all were biocompatible. Composites with 10 mg SWCNT resulted in highest rate of cell proliferation (p < 0.05) among all composites. Gene expression of alkaline phosphatase, collagen I, osteocalcin, osteopontin, Runx-2, and Bone Sialoprotein was observed on all composites. In conclusion, SWCNT/PLAGA composites imparted beneficial cellular growth capabilities and gene expression, and mineralization abilities were well established. These results demonstrate the potential of SWCNT/PLAGA composites for musculoskeletal regeneration and bone tissue engineering (BTE) and are promising for orthopedic applications. PMID:23629922

  8. Hypergolic fuel detection using individual single walled carbon nanotube networks

    SciTech Connect

    Desai, S. C.; Willitsford, A. H.; Sumanasekera, G. U.; Yu, M.; Jayanthi, C. S.; Wu, S. Y.; Tian, W. Q.

    2010-06-15

    Accurate and reliable detection of hypergolic fuels such as hydrazine (N{sub 2}H{sub 4}) and its derivatives is vital to missile defense, aviation, homeland security, and the chemical industry. More importantly these sensors need to be capable of operation at low temperatures (below room temperature) as most of the widely used chemical sensors operate at high temperatures (above 300 deg. C). In this research a simple and highly sensitive single walled carbon nanotube (SWNT) network sensor was developed for real time monitoring of hydrazine leaks to concentrations at parts per million levels. Upon exposure to hydrazine vapor, the resistance of the air exposed nanotubes (p-type) is observed to increase rapidly while that of the vacuum-degassed nanotubes (n-type) is observed to decrease. It was found that the resistance of the sample can be recovered through vacuum pumping and exposure to ultraviolet light. The experimental results support the electrochemical charge transfer mechanism between the oxygen redox couple of the ambient and the Fermi level of the SWNT. Theoretical results of the hydrazine-SWNT interaction are compared with the experimental observations. It was found that a monolayer of water molecules on the SWNT is necessary to induce strong interactions between hydrazine and the SWNT by way of introducing new occupied states near the bottom of the conduction band of the SWNT.

  9. Sorting centimetre-long single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yu, Woo Jong; Chae, Sang Hoon; Vu, Quoc An; Lee, Young Hee

    2016-08-01

    While several approaches have been developed for sorting metallic (m) or semiconducting (s) single-walled carbon nanotubes (SWCNTs), the length of SWCNTs is limited within a micrometer, which restricts excellent electrical performances of SWCNTs for macro-scale applications. Here, we demonstrate a simple sorting method of centimetre-long aligned m- and s-SWCNTs. Ni particles were selectively and uniformly coated along the 1-cm-long m-SWCNTs by applying positive gate bias during electrochemical deposition with continuous electrolyte injection. To sort s-SWCNTs, the Ni coating was oxidized to form insulator outer for blocking of current flow through inner m-SWCNTs. Sorting of m-SWCNTs were demonstrated by selective etching of s-SWCNTs via oxygen plasma, while the protected m-SWCNTs by Ni coating remained intact. The series of source-drain pairs were patterned along the 1-cm-long sorted SWCNTs, which confirmed high on/off ratio of 104–108 for s-SWCNTs and nearly 1 for m-SWCNTs.

  10. Enhanced Raman Microprobe Imaging of Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Hadjiev, V. G.; Arepalli, S.; Nikolaev, P.; Jandl, S.; Yowell, L.

    2003-01-01

    We explore Raman microprobe capabilities to visualize single wall carbon nanotubes (SWCNTs). Although this technique is limited to a micron scale, we demonstrate that images of individual SWCNTs, bundles or their agglomerates can be generated by mapping Raman active elementary excitations. We measured the Raman response from carbon vibrations in SWCNTs excited by confocal scanning of a focused laser beam. Carbon vibrations reveal key characteristics of SWCNTs as nanotube diameter distribution (radial breathing modes, RBM, 100-300 cm(exp -1)), presence of defects and functional groups (D-mode, 1300-1350 cm(exp -1)), strain and oxidation states of SWCNTs, as well as metallic or semiconducting character of the tubes encoded in the lineshape of the G-modes at 1520-1600 cm(exp - 1). In addition, SWCNTs are highly anisotropic scatterers. The Raman response from a SWCNT is maximal for incident light polarization parallel to the tube axis and vanishing for perpendicular directions. We show that the SWCNT bundle shape or direction can be determined, with some limitations, from a set of Raman images taken at two orthogonal directions of the incident light polarization.

  11. Endohedral Volume Control for Improved Single-Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Campo, Jochen; Fagan, Jeffrey

    Liquid-phase processing of single-wall carbon nanotubes (SWCNTs) generally results in the exposure of their core volumes to the environment (opening) due to energy input necessary for purification and solubilization. For aqueous processing this results in SWCNTs routinely getting filled with water, which is detrimental to several properties. Importantly, water filling leads to significant redshifts to, and inhomogeneous broadening of, the electronic transitions of the SWCNTs, as well as a substantial decrease to their fluorescence quantum efficiency. Selection of (remaining) empty (end-capped) SWCNTs to avoid these adverse effects is possible by means of ultracentrifugation, but is a natively low yield process. In this work, SWCNTs are prefilled with linear alkanes or similar organic compounds, serving as a passive, highly homogeneous spacer, blocking the ingestion of water and hence preventing the detrimental consequences. Moreover, the low dielectric nature of the alkane core only weakly affects the local electronic wavefunction of the SWCNTs, effectively simulating empty core conditions and hence yielding much more resolved optical spectra with blue shifted peak positions compared to water filled SWCNTs. It is demonstrated that a wide variety of linear as well as cyclic alkanes can be applied for this purpose, in combination with various SWCNT materials.

  12. Optical properties of armchair (7, 7) single walled carbon nanotubes

    SciTech Connect

    Gharbavi, K.; Badehian, H.

    2015-07-15

    Full potential linearized augmented plane waves method with the generalized gradient approximation for the exchange-correlation potential was applied to calculate the optical properties of (7, 7) single walled carbon nanotubes. The both x and z directions of the incident photons were applied to estimate optical gaps, dielectric function, electron energy loss spectroscopies, optical conductivity, optical extinction, optical refractive index and optical absorption coefficient. The results predict that dielectric function, ε (ω), is anisotropic since it has higher peaks along z-direction than x-direction. The static optical refractive constant were calculated about 1.4 (z-direction) and 1.1 (x- direction). Moreover, the electron energy loss spectroscopy showed a sharp π electron plasmon peaks at about 6 eV and 5 eV for z and x-directions respectively. The calculated reflection spectra show that directions perpendicular to the tube axis have further optical reflection. Moreover, z-direction indicates higher peaks at absorption spectra in low range energies. Totally, increasing the diameter of armchair carbon nanotubes cause the optical band gap, static optical refractive constant and optical reflectivity to decrease. On the other hand, increasing the diameter cause the optical absorption and the optical conductivity to increase. Moreover, the sharp peaks being illustrated at optical spectrum are related to the 1D structure of CNTs which confirm the accuracy of the calculations.

  13. Biodegradation of Single-Walled Carbon Nanotubes by Eosinophil Peroxidase

    PubMed Central

    Andón, Fernando T.; Kapralov, Alexandr A.; Yanamala, Naveena; Feng, Weihong; Baygan, Arjang; Chambers, Benedict J.; Hultenby, Kjell; Ye, Fei; Toprak, Muhammet S.; Brandner, Birgit D.; Fornara, Andrea; Klein-Seetharaman, Judith; Kotchey, Gregg P.; Star, Alexander; Shvedova, Anna A.

    2014-01-01

    Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H2O2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H2O2 alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials. PMID:23447468

  14. Buckling of single-walled carbon nanotubes using two criteria

    NASA Astrophysics Data System (ADS)

    Gupta, Shakti S.; Agrawal, Pranav; Batra, Romesh C.

    2016-06-01

    We use molecular mechanics simulations with the MM3 potential to study instabilities in clamped-clamped single-walled carbon nanotubes (SWCNTs) deformed in torsion and axial compression. The following are the two criteria employed to find the critical buckling strain: (i) a sudden drop in the potential energy and (ii) an eigenvalue of the mass weighted Hessian of the deformed configuration becoming zero. The instability under axial compression is investigated for zigzag and armchair SWCNTs, and that under torsional deformations is also studied for chiral tubes. In general, values of critical strains from the 2nd criterion are found to be substantially less than those from the 1st criterion. For chiral SWCNTs, the critical strains from the 2nd criterion and the potential energies at the onset of instability markedly depend upon the twisting direction. Values of buckling strains predicted from the column and the shell buckling theories are found to agree well with those obtained using the 2nd criterion.

  15. Bulk Mechanical Properties of Single Walled Carbon Nanotube Electrodes

    NASA Astrophysics Data System (ADS)

    Giarra, Matthew; Landi, Brian; Cress, Cory; Raffaelle, Ryne

    2007-03-01

    The unique properties of single walled carbon nanotubes (SWNTs) make them especially well suited for use as electrodes in power devices such as lithium ion batteries, hydrogen fuel cells, solar cells, and supercapacitors. The performances of such devices are expected to be influenced, at least in part, by the mechanical properties of the SWNTs used in composites or in stand alone ``papers.'' Therefore, the elastic moduli and ultimate tensile strengths of SWNT papers were measured as functions of temperature, SWNT purity, SWNT length, and SWNT bundling. The SWNTs used to produce the papers were synthesized in an alexandrite laser vaporization reactor at 1100^oC and purified using conventional acid-reflux conditions. Characterization of the SWNTs was performed using SEM, BET, TGA, and optical and Raman spectroscopy. The purified material was filtered and dried to yield papers of bundled SWNTs which were analyzed using dynamic mechanical analysis (DMA). It was observed that the mechanical properties of acid-refluxed SWNT papers were significantly improved by controlled thermal oxidation and strain-hardening. Elastic moduli of SWNT papers were measured between 3 and 6 GPa. Ultimate (breaking) tensile stresses were measured between 45 and 90 MPa at 1-3% strain. These results and their implications in regard to potential applications in power devices will be discussed.

  16. A Single-Walled Carbon Nanotube Network Gas Sensing Device

    PubMed Central

    Wang, Li-Chun; Tang, Kea-Tiong; Teng, I-Ju; Kuo, Cheng-Tzu; Ho, Cheng-Long; Kuo, Han-Wen; Su, Tseng-Hsiung; Yang, Shang-Ren; Shi, Gia-Nan; Chang, Chang-Ping

    2011-01-01

    The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT) networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD). The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3. PMID:22164044

  17. Tuning Thermoelectric Properties of Chirality Selected Single Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Yanagi, Kazuhiro; Oshima, Yuki; Kitamura, Yoshimasa; Maniwa, Yutaka

    Thermoelectrics are a very important technology for efficiently converting waste heat into electric power. Hicks and Dresselhaus proposed an important approach to innovate the performance of thermoelectric devices, which involves using one-dimensional materials and properly tuning their Fermi level (PRB 1993). Therefore, understanding the relationship between the thermoelectric performance and the Fermi level of one-dimensional materials is of great importance to maximize their thermoelectric performance. Single wall carbon nanotube (SWCNT) is an ideal model for one-dimensional materials. Previously we reported continuous p-type and n-type control over the Seebeck coefficients of semiconducting SWCNT networks with diameter of 1.4 nm through an electric double layer transistor setup using an ionic liquid as the electrolyte (Yanagi et al., Nano Lett. 14, 6437 2014). We clarified the thermoelectric properties of semiconducting SWCNTs with diameter of 1.4 nm as a function of Fermi level. In this study, we investigated how the chiralities or electronic structures of SWCNTs influence on the thermoelectric properties. We found the significant difference in the line-shape of Seebeck coefficient as a function of gate voltage between the different electronic structures of SWCNTs.

  18. Purification Procedures for Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Gorelik, Olga P.; Nikolaev, Pavel; Arepalli, Sivaram

    2001-01-01

    This report summarizes the comparison of a variety of procedures used to purify carbon nanotubes. Carbon nanotube material is produced by the arc process and laser oven process. Most of the procedures are tested using laser-grown, single-wall nanotube (SWNT) material. The material is characterized at each step of the purification procedures by using different techniques including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), Raman, X-ray diffractometry (XRD), thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR), and high-performance liquid chromatography (HPLC). The identified impurities are amorphous and graphitic carbon, catalyst particle aggregates, fullerenes, and hydrocarbons. Solvent extraction and low-temperature annealing are used to reduce the amount of volatile hydrocarbons and dissolve fullerenes. Metal catalysts and amorphous as well as graphitic carbon are oxidized by reflux in acids including HCl, HNO3 and HF and other oxidizers such as H2O2. High-temperature annealing in vacuum and in inert atmosphere helps to improve the quality of SWNTs by increasing crystallinity and reducing intercalation.

  19. Observation and Modeling of Single Wall Carbon Nanotube Bend Junctions

    NASA Technical Reports Server (NTRS)

    Han, Jie; Anantram, M. P.; Jaffe, R. L.; Kong, J.; Dai, H.; Saini, Subhash (Technical Monitor)

    1998-01-01

    Single wall carbon nanotube (SWNT) bends, with diameters from approx. 1.0 to 2.5 nm and bend angles from 18 deg. to 34 deg., are observed in catalytic decomposition of hydrocarbons at 600 - 1200 C. An algorithm using molecular dynamics simulation (MD) techniques is developed to model these structures that are considered to be SWNT junctions formed by topological defects (i.e. pentagon-heptagon pairs). The algorithm is used to predict the tube helicities and defect configurations for bend junctions using the observed tube diameters and bend angles. The number and arrangement of the defects at the junction interfaces are found to depend on the tube helicities and bend angle. The structural and energetic calculations using the Brenner potential show a number of stable junction configurations for each bend angle with the 34 deg. bends being more stable than the others. Tight binding calculations for local density of state (LDOS) and transmission coefficients are carried out to investigate electrical properties of the bend junctions.

  20. Sorting centimetre-long single-walled carbon nanotubes

    PubMed Central

    Yu, Woo Jong; Chae, Sang Hoon; Vu, Quoc An; Lee, Young Hee

    2016-01-01

    While several approaches have been developed for sorting metallic (m) or semiconducting (s) single-walled carbon nanotubes (SWCNTs), the length of SWCNTs is limited within a micrometer, which restricts excellent electrical performances of SWCNTs for macro-scale applications. Here, we demonstrate a simple sorting method of centimetre-long aligned m- and s-SWCNTs. Ni particles were selectively and uniformly coated along the 1-cm-long m-SWCNTs by applying positive gate bias during electrochemical deposition with continuous electrolyte injection. To sort s-SWCNTs, the Ni coating was oxidized to form insulator outer for blocking of current flow through inner m-SWCNTs. Sorting of m-SWCNTs were demonstrated by selective etching of s-SWCNTs via oxygen plasma, while the protected m-SWCNTs by Ni coating remained intact. The series of source-drain pairs were patterned along the 1-cm-long sorted SWCNTs, which confirmed high on/off ratio of 104–108 for s-SWCNTs and nearly 1 for m-SWCNTs. PMID:27476909

  1. Reinforced Thermoplastic Polyimide with Dispersed Functionalized Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Lebron-Colon, Marisabel; Meador, Michael A.; Gaier, James R.; Sola, Francisco; Scheiman, Daniel A.; McCorkle, Linda S.

    2010-01-01

    Molecular pi-complexes were formed from pristine HiPCO single-wall carbon nanotubes (SWCNTs) and 1-pyrene- N-(4- N'-(5-norbornene-2,3-dicarboxyimido)phenyl butanamide, 1. Polyimide films were prepared with these complexes as well as uncomplexed SWCNTs and the effects of nanoadditive addition on mechanical, thermal, and electrical properties of these films were evaluated. Although these properties were enhanced by both nanoadditives, larger increases in tensile strength and thermal and electrical conductivities were obtained when the SWCNT/1 complexes were used. At a loading level of 5.5 wt %, the Tg of the polyimide increased from 169 to 197 C and the storage modulus increased 20-fold (from 142 to 3045 MPa). The addition of 3.5 wt % SWCNT/1 complexes increased the tensile strength of the polyimide from 61.4 to 129 MPa; higher loading levels led to embrittlement and lower tensile strengths. The electrical conductivities (DC surface) of the polyimides increased to 1 x 10(exp -4) Scm(exp -1) (SWCNT/1 complexes loading level of 9 wt %). Details of the preparation of these complexes and their effects on polyimide film properties are discussed.

  2. Nonlinear resonances of a single-wall carbon nanotube cantilever

    NASA Astrophysics Data System (ADS)

    Kim, I. K.; Lee, S. I.

    2015-03-01

    The dynamics of an electrostatically actuated carbon nanotube (CNT) cantilever are discussed by theoretical and numerical approaches. Electrostatic and intermolecular forces between the single-walled CNT and a graphene electrode are considered. The CNT cantilever is analyzed by the Euler-Bernoulli beam theory, including its geometric and inertial nonlinearities, and a one-mode projection based on the Galerkin approximation and numerical integration. Static pull-in and pull-out behaviors are adequately represented by an asymmetric two-well potential with the total potential energy consisting of the CNT elastic energy, electrostatic energy, and the Lennard-Jones potential energy. Nonlinear dynamics of the cantilever are simulated under DC and AC voltage excitations and examined in the frequency and time domains. Under AC-only excitation, a superharmonic resonance of order 2 occurs near half of the primary frequency. Under both DC and AC loads, the cantilever exhibits linear and nonlinear primary and secondary resonances depending on the strength of the excitation voltages. In addition, the cantilever has dynamic instabilities such as periodic or chaotic tapping motions, with a variation of excitation frequency at the resonance branches. High electrostatic excitation leads to complex nonlinear responses such as softening, multiple stability changes at saddle nodes, or period-doubling bifurcation points in the primary and secondary resonance branches.

  3. Single-Walled Carbon Nanotube Transporter for Gene Delivery

    NASA Astrophysics Data System (ADS)

    Ke, Pu-Chun

    2005-03-01

    Recent studies have shown great promises in integrating nanomaterials in biomedicine. To explore the feasibility of using single-walled carbon nanotubes (SWNTs) as transporters for gene delivery, we have investigated the binding of SWNTs and RNA polymer poly(rU), and the diffusion and the translocation of the SWNT-poly(rU) complexes. Through single-molecule fluorescence imaging, we have found that the pi- stacking dominates the hydrophobic interactions between the carbon rings on tubes and the nitrogenous bases of RNA. Our diffusion study has further demonstrated the feasibility of tracking the motion of water soluble SWNT-poly(rU) complexes. The uptake of SWNT-poly(rU) by breast cancer cells MCF7 was observed using confocal scanning fluorescence microscopy. It was evident that the complexes could penetrate through cell membrane into cytoplasm and cell nucleus. Our cell culture, MTS assay, and radioisotope labeling showed the negligible cytotoxicity of surface modified SWNTs with RNA polymer and amino acids in cell growth medium. These studies have paved the way for gene transfection using SWNTs as transporters.

  4. Chirality Characterization of Dispersed Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Namkung, Min; Williams, Phillip A.; Mayweather, Candis D.; Wincheski, Buzz; Park, Cheol; Namkung, Juock S.

    2005-01-01

    Raman scattering and optical absorption spectroscopy are used for the chirality characterization of HiPco single wall carbon nanotubes (SWNTs) dispersed in aqueous solution with the surfactant sodium dodecylbenzene sulfonate. Radial breathing mode (RBM) Raman peaks for semiconducting and metallic SWNTs are identified by directly comparing the Raman spectra with the Kataura plot. The SWNT diameters are calculated from these resonant peak positions. Next, a list of (n, m) pairs, yielding the SWNT diameters within a few percent of that obtained from each resonant peak position, is established. The interband transition energies for the list of SWNT (n, m) pairs are calculated based on the tight binding energy expression for each list of the (n, m) pairs, and the pairs yielding the closest values to the corresponding experimental optical absorption peaks are selected. The results reveal that (1, 11), (4, 11), and (0, 11) as the most probable chiralities of the semiconducting nanotubes. The results also reveal that (4, 16), (6, 12) and (8, 8) are the most probable chiralities for the metallic nanotubes. Directly relating the Raman scattering data to the optical absorption spectra, the present method is considered the simplest technique currently available. Another advantage of this technique is the use of the E(sup 8)(sub 11) peaks in the optical absorption spectrum in the analysis to enhance the accuracy in the results.

  5. Single-Walled Carbon-Nanotubes-Based Organic Memory Structures.

    PubMed

    Fakher, Sundes; Nejm, Razan; Ayesh, Ahmad; Al-Ghaferi, Amal; Zeze, Dagou; Mabrook, Mohammed

    2016-01-01

    The electrical behaviour of organic memory structures, based on single-walled carbon-nanotubes (SWCNTs), metal-insulator-semiconductor (MIS) and thin film transistor (TFT) structures, using poly(methyl methacrylate) (PMMA) as the gate dielectric, are reported. The drain and source electrodes were fabricated by evaporating 50 nm gold, and the gate electrode was made from 50 nm-evaporated aluminium on a clean glass substrate. Thin films of SWCNTs, embedded within the insulating layer, were used as the floating gate. SWCNTs-based memory devices exhibited clear hysteresis in their electrical characteristics (capacitance-voltage (C-V) for MIS structures, as well as output and transfer characteristics for transistors). Both structures were shown to produce reliable and large memory windows by virtue of high capacity and reduced charge leakage. The hysteresis in the output and transfer characteristics, the shifts in the threshold voltage of the transfer characteristics, and the flat-band voltage shift in the MIS structures were attributed to the charging and discharging of the SWCNTs floating gate. Under an appropriate gate bias (1 s pulses), the floating gate is charged and discharged, resulting in significant threshold voltage shifts. Pulses as low as 1 V resulted in clear write and erase states. PMID:27598112

  6. Single-Wall Carbon Nanotube Anodes for Lithium Cells

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Raffaelle, Ryne; Gennett, Tom; Kumta, Prashant; Maranchi, Jeff; Heben, Mike

    2006-01-01

    In recent experiments, highly purified batches of single-wall carbon nanotubes (SWCNTs) have shown promise as superior alternatives to the graphitic carbon-black anode materials heretofore used in rechargeable thin-film lithium power cells. The basic idea underlying the experiments is that relative to a given mass of graphitic carbon-black anode material, an equal mass of SWCNTs can be expected to have greater lithium-storage and charge/discharge capacities. The reason for this expectation is that whereas the microstructure and nanostructure of a graphitic carbon black is such as to make most of the interior of the material inaccessible for intercalation of lithium, a batch of SWCNTs can be made to have a much more open microstructure and nanostructure, such that most of the interior of the material is accessible for intercalation of lithium. Moreover, the greater accessibility of SWCNT structures can be expected to translate to greater mobilities for ion-exchange processes and, hence, an ability to sustain greater charge and discharge current densities.

  7. Hypergolic fuel detection using individual single walled carbon nanotube networks

    NASA Astrophysics Data System (ADS)

    Desai, S. C.; Willitsford, A. H.; Sumanasekera, G. U.; Yu, M.; Tian, W. Q.; Jayanthi, C. S.; Wu, S. Y.

    2010-06-01

    Accurate and reliable detection of hypergolic fuels such as hydrazine (N2H4) and its derivatives is vital to missile defense, aviation, homeland security, and the chemical industry. More importantly these sensors need to be capable of operation at low temperatures (below room temperature) as most of the widely used chemical sensors operate at high temperatures (above 300 °C). In this research a simple and highly sensitive single walled carbon nanotube (SWNT) network sensor was developed for real time monitoring of hydrazine leaks to concentrations at parts per million levels. Upon exposure to hydrazine vapor, the resistance of the air exposed nanotubes (p-type) is observed to increase rapidly while that of the vacuum-degassed nanotubes (n-type) is observed to decrease. It was found that the resistance of the sample can be recovered through vacuum pumping and exposure to ultraviolet light. The experimental results support the electrochemical charge transfer mechanism between the oxygen redox couple of the ambient and the Fermi level of the SWNT. Theoretical results of the hydrazine-SWNT interaction are compared with the experimental observations. It was found that a monolayer of water molecules on the SWNT is necessary to induce strong interactions between hydrazine and the SWNT by way of introducing new occupied states near the bottom of the conduction band of the SWNT.

  8. Electrical characterization of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Berliocchi, Marco; Brunetti, Francesca; Di Carlo, Aldo; Lugli, Paolo; Orlanducci, Silvia; Terranova, Maria Letizia

    2003-04-01

    Single Wall Carbon Nanotubes (SWCNTs) based nanotechnology appears to be promising for future nanoelectronics. The SWCNT may be either metallic or semiconducting and both metallic and semiconducting types of SWCNTs have been observed experimentally. This gives rise to intriguing possibilities to put together semiconductor-semiconductor and semiconductor-metal junctions for diodes and transistors. The potential for nanotubes in nanoelectronics devices, displays and nanosensors is enormous. However, in order to realize the potential of SWCNTs, it is critical to understand the properties of charge transport and to control phase purity, elicity and arrangement according to specific architectures. We have investigated the electrical properties of various SWCNTs samples whit different organization: bundles of SWCNTs, SWCNT fibres and different membranes and tablets obtained using SWCNTs purified and characterized. Electrical characterizations were carried out by a 4155B Agilent Semiconductor Parameter Analyser. In order to give a mechanical stability to SWCNTs fibres and bundles we have used a nafion matrix coating, so an electrical characterization has been performed on samples with and without this layer. I-V measurements were performed in vacuum and in air using aluminium interdigitated coplanar-electrodes (width=20mm or 40mm) on glass substrates. The behaviour observed is generally supralinear with currents of the order of mA in vacuum and lower values in air with the exception of the tablet samples where the behaviour is ohmic, the currents are higher and similar values of current are detected in air and vacuum.

  9. Ultrathin single-walled carbon nanotube network framed graphene hybrids.

    PubMed

    Wang, Rui; Hong, Tu; Xu, Ya-Qiong

    2015-03-11

    Graphene and single-walled carbon nanotubes (SWNTs) have shown superior potential in electronics and optoelectronics because of their excellent thermal, mechanical, electronic, and optical properties. Here, a simple method is developed to synthesize ultrathin SWNT-graphene films through chemical vapor deposition. These novel two-dimensional hybrids show enhanced mechanical strength that allows them to float on water without polymer supporting layers. Characterizations by Raman spectroscopy and transmission electron microscopy indicate that SWNTs can interlace as a concrete backbone for the subsequent growth of monolayer graphene. Optical and electrical transport measurements further show that SWNT-graphene hybrids inherit high optical transparency and superior electrical conductivity from monolayer graphene. We also explore the local optoelectronic properties of SWNT-graphene hybrids through spatially resolved photocurrent microscopy and find that the interactions between SWNTs and graphene can induce a strong photocurrent response in the areas where SWNTs link different graphene domains together. These fundamental studies may open a door for engineering optoelectronic properties of SWNT-graphene hybrids by controlling the morphologies of the SWNT frames. PMID:25686199

  10. Phosphatidylserine in the Brain: Metabolism and Function

    PubMed Central

    Kim, Hee-Yong; Huang, Bill X.; Spector, Arthur A.

    2014-01-01

    Phosphatidylserine (PS) is the major anionic phospholipid class particularly enriched in the inner leaflet of the plasma membrane in neural tissues. PS is synthesized from phosphatidylcholine or phosphatidylethanolamine by exchanging the base head group with serine in reactions are catalyzed by phosphatidylserine synthase 1 and phosphatidylserine synthase 2 located in the endoplasmic reticulum. Activation of Akt, Raf-1 and protein kinase C signaling, which supports neuronal survival and differentiation, requires interaction of these proteins with PS localized in the cytoplasmic leaflet of the plasma membrane. Furthermore, neurotransmitter release by exocytosis and a number of synaptic receptors and proteins are modulated by PS present in the neuronal membranes. Brain is highly enriched with docosahexaenoic acid (DHA), and brain PS has a high DHA content. By promoting PS synthesis, DHA can uniquely expand the PS pool in neuronal membranes and thereby influence PS-dependent signaling and protein function. Ethanol decreases DHA-promoted PS synthesis and accumulation in neurons, which may contribute to the deleterious effects of ethanol intake. Improvement of some memory functions has been observed in cognitively impaired subjects as a result of PS supplementation, but the mechanism is unclear. PMID:24992464

  11. Toroidal Single Wall Carbon Nanotubes in Fullerene Crop Circles

    NASA Technical Reports Server (NTRS)

    Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    We investigate energetics and structure of circular and polygonal single wall carbon nanotubes (SWNTs) using large scale molecular simulations on NAS SP2, motivated by their unusual electronic and magnetic properties. The circular tori are formed by bending tube (no net whereas the polygonal tori are constructed by turning the joint of two tubes of (n, n), (n+1, n-1) and (n+2, n-2) with topological pentagon-heptagon defect, in which n =5, 8 and 10. The strain energy of circular tori relative to straight tube decreases by I/D(sup 2) where D is torus diameter. As D increases, these tori change from buckling to an energetically stable state. The stable tori are perfect circular in both toroidal and tubular geometry with strain less than 0. 03 eV/atom when D greater than 10, 20 and 40 nm for torus (5,5), (8,8) and (10, 10). Polygonal tori, whose strain is proportional to the number of defects and I/D are energetically stable even for D less than 10 nm. However, their strain is higher than that of perfect circular tori. In addition, the local maximum strain of polygonal tori is much higher than that of perfect circular tori. It is approx. 0.03 eV/atom or less for perfect circular torus (5,5), but 0.13 and 0.21 eV/atom for polygonal tori (6,4)/(5,5) and (7,3)/(5,5). Therefore, we conclude that the circular tori with no topological defects are more energetically stable and kinetically accessible than the polygonal tori containing the pentagon-heptagon defects for the laser-grown SWNTs and Fullerene crop circles.

  12. Elastomer Filled With Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Files, Bradley S.; Forest, Craig R.

    2004-01-01

    Experiments have shown that composites of a silicone elastomer with single-wall carbon nanotubes (SWNTs) are significantly stronger and stiffer than is the unfilled elastomer. The large strengthening and stiffening effect observed in these experiments stands in contrast to the much smaller strengthening effect observed in related prior efforts to reinforce epoxies with SWNTs and to reinforce a variety of polymers with multiple-wall carbon nanotubes (MWNTs). The relative largeness of the effect in the case of the silicone-elastomer/SWNT composites appears to be attributable to (1) a better match between the ductility of the fibers and the elasticity of the matrix and (2) the greater tensile strengths of SWNTs, relative to MWNTs. For the experiments, several composites were formulated by mixing various proportions of SWNTs and other filling materials into uncured RTV-560, which is a silicone adhesive commonly used in aerospace applications. Specimens of a standard "dog-bone" size and shape for tensile testing were made by casting the uncured elastomer/filler mixtures into molds, curing the elastomer, then pressing the specimens from a "cookie-cutter" die. The results of tensile tests of the specimens showed that small percentages of SWNT filler led to large increases in stiffness and tensile strength, and that these increases were greater than those afforded by other fillers. For example, the incorporation of SWNTs in a proportion of 1 percent increased the tensile strength by 44 percent and the modulus of elasticity (see figure) by 75 percent. However, the relative magnitudes of the increases decreased with increasing nanotube percentages because more nanotubes made the elastomer/nanotube composites more brittle. At an SWNT content of 10 percent, the tensile strength and modulus of elasticity were 125 percent and 562 percent, respectively, greater than the corresponding values for the unfilled elastomer.

  13. Single-walled carbon nanotube networks in conductive composite materials.

    PubMed

    Bârsan, Oana A; Hoffmann, Günter G; van der Ven, Leo G J; de With, G Bert

    2014-01-01

    Electrically conductive composite materials can be used for a wide range of applications because they combine the advantages of a specific polymeric material (e.g., thermal and mechanical properties) with the electrical properties of conductive filler particles. However, the overall electrical behaviour of these composite materials is usually much below the potential of the conductive fillers, mainly because by mixing two different components, new interfaces and interphases are created, changing the properties and behaviours of both. Our goal is to characterize and understand the nature and influence of these interfaces on the electrical properties of composite materials. We have improved a technique based on the use of sodium carboxymethyl cellulose (CMC) to disperse single-walled carbon nanotubes (SWCNTs) in water, followed by coating glass substrates, and drying and removing the CMC with a nitric acid treatment. We used electron microscopy and atomic force microscopy techniques to characterize the SWCNT films, and developed an in situ resistance measurement technique to analyse the influence of both the individual components and the mixture of an epoxy/amine system on the electrical behaviour of the SWCNTs. The results showed that impregnating a SWCNT network with a polymer is not the only factor that affects the film resistance; air exposure, temperature, physical and chemical properties of the individual polymer components, and also the formation of a polymeric network, can all have an influence on the macroscopic electrical properties of the initial SWCNT network. These results emphasize the importance of understanding the effects that each of the components can have on each other before trying to prepare an efficient polymer composite material. PMID:25430670

  14. Spectroscopy-Based Characterization of Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Namkung, Min; Namkung, Juock S.; Wincheski, Russell A.; Seo, J.; Park, Cheol

    2003-01-01

    We present the initial results of our combined investigation of Raman scattering and optical absorption spectroscopy in a batch of single wall carbon nanotubes (SWNTs). The SWNT diameters are first estimated from the four radial breathing mode (RBM) peaks using a simple relation of omega(sub RBM) = 248/cm nm/d(sub t)(nm). The calculated diameter values are related to the optical absorption peaks through the expressions of first interband transition energies, i.e., E(sup S)(sub 11) = 2a gamma/d(sub t) for semiconducting and E(sup S)(sub 11) = 6a gamma/d(sub t) for metallic SWNTs, respectively, where a is the carbon-carbon bond length (0.144 nm) and gamma is the energy of overlapping electrons from nearest neighbor atoms, which is 2.9 eV for a SWNT. This analysis indicates that three RBM peaks are from semiconducting tubes, and the remaining one is from metallic tubes. The detailed analysis in the present study is focused on these three peaks of the first absorption band by determining the values of the representative (n,m) pairs. The first step of analysis is to construct a list of possible (n,m) pairs from the diameters calculated from the positions of the RBM peaks. The second step is to compute the first interband transition energy, E(sub 11), by substituting the constructed list of (n,m) into the expression of Reich and Thomsen, and Saito et al. Finally, the pairs with the energies closest to the experimental values are selected.

  15. Superemission in vertically-aligned single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Khmelinskii, Igor; Makarov, Vladimir

    2016-09-01

    Presently we used two samples of vertically aligned single-wall carbon nanotubes (VA SWCNTs) with parallelepiped geometry, sized 0.02 cm × 0.2 cm × 1.0 cm and 0.2 cm × 0.2 cm × 1.0 cm. We report absorption and emission properties of the VA SWCNTs, including strong anisotropy in both their absorption and emission spectra. We found that the emission spectra extend from the middle-IR range to the near-IR range, with such extended spectra being reported for the first time. Pumping the VA SWCNTs in the direction normal to their axis, superemission (SE) was observed in the direction along their axis. The SE band maximum is located at 7206 ± 0.4 cm-1. The energy and the power density of the superemission were estimated, along with the diffraction-limited divergence. At the pumping energy of 3 mJ/pulse, the SE energy measured by the detector was 0.74 mJ/pulse, corresponding to the total SE energy of 1.48 mJ/pulse, with the energy density of 18.5 mJ cm-2/pulse and the SE power density of 1.2 × 105 W cm-2/pulse. We report that a bundle of VA SWCNTs is an emitter with a relatively small divergence, not exceeding 3.9 × 10-3 rad. We developed a theoretical approach to explain such absorption and emission spectra. The developed theory is based on the earlier proposed SSH theory, which we extended to include the exchange interactions between the closest SWCNT neighbors. The developed theoretical ideas were implemented in a homemade FORTRAN code. This code was successfully used to calculate and reproduce the experimental spectra and to determine the SWCNT species that originate the respective absorption bands, with acceptable agreement between theory and experiment.

  16. Self-assembling Functionalized Single-walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Gao, Yan

    Single-walled carbon nanotubes (SWCNTs) are promising bottom-up building materials due to their superior properties. However, the lack of an effective method to arrange large quantities of SWCNTs poses an obstacle toward their applications. Existing studies to functionalize, disperse, position, and assemble SWCNTs provide a broad understandings regarding SWCNTs behavior, especially in aqueous electrolyte solution. Inspired by ionic polymer metal composite (IPMC) materials, this dissertation envisions fabrication of orderly SWCNTs network structure via their ionic clustering-mediated self-assembly. SWCNTs tend to bundle together due to inter-nanotube VDW attractions, which increase with nanotube length. The author seeks short SWCNTs with long chain molecules bearing ionic termini to facilitate debundling and self-assembly in aqueous electrolyte solution through end-clustering. First, a simple model was applied based on essential physical factors. The results indicated that SWCNTs must be shorter than ˜100 nm to achieve stable network structures. Experiments were then carried out based upon the results. Short SWCNTs (50-100 nm) were end-functionalized with hexaethylene glycol (HEG) linkers bearing terminal carboxylate anions. Both 2D and 3D network structures were observed after placing the functionalized SWCNTs in aqueous electrolyte (sodium ion). The network structures were characterized by microscopic and spectroscopic methods. A novel approach was applied via electron tomography to study the 3D structures of SWCNTs structure in aqueous electrolyte. Free energy analysis of the SWCNTs network structure was implemented with the assistance of both analytical tools and molecular simulations. The results indicate that, when a cluster is formed by three functionalized SWCNTs ends, the resulting network structure is most stable. Indeed, 72% of the clusters/joints were formed by three nanotubes, as observed in experiments. Finally, Monte Carlo simulations of coarse

  17. Photovoltaic device using single wall carbon nanotubes and method of fabricating the same

    DOEpatents

    Biris, Alexandru S.; Li, Zhongrui

    2012-11-06

    A photovoltaic device and methods for forming the same. In one embodiment, the photovoltaic device has a silicon substrate, and a film comprising a plurality of single wall carbon nanotubes disposed on the silicon substrate, wherein the plurality of single wall carbon nanotubes forms a plurality of heterojunctions with the silicon in the substrate.

  18. Study on the Microwave Permittivity of Single-Walled Carbon Nanotube

    ERIC Educational Resources Information Center

    Liu, Xiaolai; Zhao, Donglin

    2009-01-01

    In this article, we studied the microwave permittivity of the complex of the single-walled carbon nanotube and paraffin in 2-18GHz. In the range, the dielectric loss of single-walled carbon nanotube is higher, and the real part and the imaginary part of the dielectric constant decrease with the increase of frequency, and the dielectric constant…

  19. Regulation of singlet oxygen generation using single-walled carbon nanotubes.

    PubMed

    Zhu, Zhi; Tang, Zhiwen; Phillips, Joseph A; Yang, Ronghua; Wang, Hui; Tan, Weihong

    2008-08-20

    We have designed a novel photodynamic therapy (PDT) agent using protein binding aptamer, photosensitizer, and single-walled carbon nanotube (SWNT). The PDT is based on covalently linking a photosensitizer with an aptamer then wrapping onto the surface of SWNTs, such that the photosensitizer can only be activated by light upon target binding. We have chosen the human alpha-thrombin aptamer and covalently linked it with Chlorin e6 (Ce6), which is a second generation photosensitizer. Our results showed that SWNTs are great quenchers to singlet oxygen generation (SOG). In the presence of its target, the binding of target thrombin will disturb the DNA interaction with the SWNTs and cause the DNA aptamer to fall off the SWNT surface, resulting in the restoration of SOG. This study validated the potential of our design as a novel PDT agent with regulation by target molecules, enhanced specificity, and efficacy of therapeutic function, which directs the development of photodynamic therapy to be safer and more selective. PMID:18661988

  20. Single Walled Carbon Nanohorns as Photothermal Cancer Agents

    SciTech Connect

    Whitney, John; Sarkar, Saugata; Zhang, Jianfei; Do, Thao; Manson, Mary kyle; Campbell, Tom; Puretzky, Alexander A; Rouleau, Christopher M; More, Karren Leslie; Geohegan, David B; Rylander, Christopher; Dorn, Harry C; Rylander, Nichole M

    2011-01-01

    Nanoparticles have significant potential as selective photo-absorbing agents for laser based cancer treatment. This study investigates the use of single walled carbon nanohorns (SWNHs) as thermal enhancers when excited by near infrared (NIR) light for tumor cell destruction. Absorption spectra of SWNHs in deionized water at concentrations of 0, 0.01, 0.025, 0.05, 0.085, and 0.1 mg/ml were measured using a spectrophotometer for the wavelength range of 200-1,400 nm. Mass attenuation coefficients were calculated using spectrophotometer transmittance data. Cell culture media containing 0, 0.01, 0.085, and 0.333 mg/ml SWNHs was laser irradiated at 1,064 nm wavelength with an irradiance of 40 W/cm{sup 2} for 0-5 minutes. Temperature elevations of these solutions during laser irradiation were measured with a thermocouple 8 mm away from the incident laser beam. Cell viability of murine kidney cancer cells (RENCA) was measured 24 hours following laser treatment with the previously mentioned laser parameters alone or with SWNHs. Cell viability as a function of radial position was determined qualitatively using trypan blue staining and bright field microscopy for samples exposed to heating durations of 2 and 6 minutes alone or with 0.085 mg/ml SWNHs. A Beckman Coulter Vi-Cell instrument quantified cell viability of samples treated with varying SWNH concentration (0, 0.01, 0.085, and 0.333 mg/ml) and heating durations of 0-6 minutes. Spectrophotometer measurements indicated inclusion of SWNHs increased light absorption and attenuation across all wavelengths. Utilizing SWNHs with laser irradiation increased temperature elevation compared to laser heating alone. Greater absorption and higher temperature elevations were observed with increasing SWNH concentration. No inherent toxicity was observed with SWNH inclusion. A more rapid and substantial viability decline was observed over time in samples exposed to SWNHs with laser treatment compared with samples experiencing laser

  1. Structural characterization of macroscopic single-walled carbon nanotube materials

    NASA Astrophysics Data System (ADS)

    Zhou, Wei

    In this thesis, we studied the structural properties of macroscopic materials of single-walled carbon nanotubes (SWNTs) in the form of fibers, films and suspensions. We characterized the preferred orientations in partially aligned SWNT fibers and films, combining x-ray fiber diagram and polarized Raman scattering. Our texture model consists of an aligned fraction, characterized by the angular distribution width of tube axes, plus a completely unaligned fraction. For neat fibers extruded from SWNT/superacid suspensions through a small orifice, the distribution width and the aligned fraction both improve with decreasing orifice diameter. For magnetic field-aligned SWNT films deposited from surfactant suspensions, the aligning effects of deposition and external magnetic field force in the film plane are additive, the out-of-plane mosaic being narrower than the in-plane one. SWNTs dispersed in superacid or aqueous surfactant solutions are precursors for many applications. In oleum, SWNTs can be charged and protonated by H 2SO4 molecules. X-ray scattering indicates that H2SO 4 molecules align along nanotube axes to form cylindrical shells wrapped around nanotubes. This finding establishes the validity of a long-standing important but still debated physical chemistry concept, "structured solvent shells surrounding dissolved ions". Differential scanning calorimetry confirms that the partly ordered H2SO4 molecules are a new phase, with distinct freezing/melting behavior. X-ray scattering at low temperature further shows that crystallization of the bulk-like acid surrounding the structured shells is templated by the SWNTs. The specific orientation of the acid crystallites provides solid evidence for direct protonation of SWNT. We studied the morphologies of SWNT suspensions using small-angle neutron scattering. We observed rigid rod behavior from SWNTs dispersed in water using sodium dodecylbenzene sulfonate surfactant, suggesting that SWNTs exist mainly as individual tube

  2. Antimicrobial Biomaterials based on Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Aslan, Seyma

    Biomaterials that inactivate bacteria are needed to eliminate medical device infections. We investigate the antimicrobial nature of single-walled carbon nanotubes (SWNT) incorporated within biomedical polymers. In the first part, we focus on SWNT dispersed in the common biomedical polymer poly(lactic-co-glycolic acid) (PLGA) as a potential antimicrobial biomaterial. We find Escherichia coli and Staphylococcus epidermidis viability and metabolic activity to be significantly diminished in the presence of SWNT-PLGA, and to correlate with SWNT length and concentration. Up to 98 % of bacteria die within one hour of SWNT-PLGA versus 15-20% on pure PLGA. Shorter SWNT are found to be more toxic, possibly due to an increased density of open tube ends. In the second part, we investigate the antimicrobial activity of SWNT layer-by-layer (LbL) assembled with the polyelectrolytes poly(L-lysine) (PLL) and poly(L-glutamic acid) (PGA). The dispersibility of SWNT in aqueous solution is significantly improved via the biocompatible nonionic surfactant polyoxyethylene(20)sorbitan monolaurate (Tween 20) and the amphiphilic polymer phospholipid-poly(ethylene glycol) (PL-PEG). Absorbance spectroscopy and transmission electron microscopy (TEM) show SWNT with either Tween 20 or PL-PEG in aqueous solution to be well dispersed. Quartz crystal microgravimetry with dissipation (QCMD) measurements show both SWNT-Tween and SWNT-PL-PEG to LbL assemble with PLL and PGA into multilayer films, with the PL-PEG system yielding the greater final SWNT content. Bacterial inactivation rates are significantly higher (up to 90%) upon 24 hour incubation with SWNT containing films, compared to control films (ca. 20%). In the third part, we study the influence of bundling on the LbL assembly of SWNT with charged polymers, and on the antimicrobial properties of the assembled film. QCMD measurements show the bundled SWNT system to adsorb in an unusually strong fashion—to an extent three times greater than that

  3. Single-walled carbon nanotube-induced mitotic disruption⋆

    PubMed Central

    Sargent, L.M.; Hubbs, A.F.; Young, S.-H.; Kashon, M.L.; Dinu, C.Z.; Salisbury, J.L.; Benkovic, S.A.; Lowry, D.T.; Murray, A.R.; Kisin, E.R.; Siegrist, K.J.; Battelli, L.; Mastovich, J.; Sturgeon, J.L.; Bunker, K.L.; Shvedova, A.A.; Reynolds, S.H.

    2015-01-01

    Carbon nanotubes were among the earliest products of nanotechnology and have many potential applications in medicine, electronics, and manufacturing. The low density, small size, and biological persistence of carbon nanotubes create challenges for exposure control and monitoring and make respiratory exposures to workers likely. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to 24, 48 and 96 μg/cm2 single-walled carbon nanotubes (SWCNT). To investigate mitotic spindle aberrations at concentrations anticipated in exposed workers, primary and immortalized human airway epithelial cells were exposed to SWCNT for 24–72 h at doses equivalent to 20 weeks of exposure at the Permissible Exposure Limit for particulates not otherwise regulated. We have now demonstrated fragmented centrosomes, disrupted mitotic spindles and aneuploid chromosome number at those doses. The data further demonstrated multipolar mitotic spindles comprised 95% of the disrupted mitoses. The increased multipolar mitotic spindles were associated with an increased number of cells in the G2 phase of mitosis, indicating a mitotic checkpoint response. Nanotubes were observed in association with mitotic spindle microtubules, the centrosomes and condensed chromatin in cells exposed to 0.024, 0.24, 2.4 and 24 μg/cm2 SWCNT. Three-dimensional reconstructions showed carbon nanotubes within the centrosome structure. The lower doses did not cause cytotoxicity or reduction in colony formation after 24 h; however, after three days, significant cytotoxicity was observed in the SWCNT-exposed cells. Colony formation assays showed an increased proliferation seven days after exposure. Our results show significant disruption of the mitotic spindle by SWCNT at occupationally relevant doses. The increased proliferation that was observed in carbon nanotube-exposed cells indicates a greater potential to pass the genetic damage to daughter

  4. Cytotoxic effect of poly-dispersed single walled carbon nanotubes on erythrocytes in vitro and in vivo.

    PubMed

    Sachar, Sumedha; Saxena, Rajiv K

    2011-01-01

    Single wall Carbon Nanotubes (SWCNTs) are hydrophobic and do not disperse in aqueous solvents. Acid functionalization of SWCNTs results in attachment of carboxy and sulfonate groups to carbon atoms and the resulting acid functionalized product (AF-SWCNTs) is negatively charged and disperses easily in water and buffers. In the present study, effect of AF-SWCNTs on blood erythrocytes was examined. Incubation of mouse erythrocytes with AF-SWCNTs and not with control SWCNTs, resulted in a dose and time dependent lysis of erythrocyte. Using fluorescence tagged AF-SWCNTs, binding of AF-SWCNTs with erythrocytes could be demonstrated. Confocal microscopy results indicated that AF-SWCNTs could enter the erythrocytes. Treatment with AF-SWCNTs resulted in exposure of hydrophobic patches on erythrocyte membrane that is indicative of membrane damage. A time and dose dependent increase in externalization of phosphatidylserine on erythrocyte membrane bilayer was also found. Administration of AF-SWCNTs through intravenous route resulted in a transient anemia as seen by a sharp decline in blood erythrocyte count accompanied with a significant drop in blood haemoglobin level. Administration of AF-SWCNTs through intratracheal administration also showed significant decline in RBC count while administration through other routes (gavage and intra-peritoneal) was not effective. By using a recently developed technique of a two step in vivo biotinylation of erythrocytes that enables simultaneous enumeration of young (age <10 days) and old (age>40 days) erythrocytes in mouse blood, it was found that the in vivo toxic effect of AF-SWCNTs was more pronounced on older subpopulation of erythrocytes. Subpopulation of old erythrocytes fell after treatment with AF-SWCNTs but recovered by third day after the intravenous administration of AF-SWCNTs. Taken together our results indicate that treatment with AF-SWCNTs results in acute membrane damage and eventual lysis of erythrocytes. Intravenous

  5. Cytotoxic Effect of Poly-Dispersed Single Walled Carbon Nanotubes on Erythrocytes In Vitro and In Vivo

    PubMed Central

    Sachar, Sumedha; Saxena, Rajiv K.

    2011-01-01

    Single wall Carbon Nanotubes (SWCNTs) are hydrophobic and do not disperse in aqueous solvents. Acid functionalization of SWCNTs results in attachment of carboxy and sulfonate groups to carbon atoms and the resulting acid functionalized product (AF-SWCNTs) is negatively charged and disperses easily in water and buffers. In the present study, effect of AF-SWCNTs on blood erythrocytes was examined. Incubation of mouse erythrocytes with AF-SWCNTs and not with control SWCNTs, resulted in a dose and time dependent lysis of erythrocyte. Using fluorescence tagged AF-SWCNTs, binding of AF-SWCNTs with erythrocytes could be demonstrated. Confocal microscopy results indicated that AF-SWCNTs could enter the erythrocytes. Treatment with AF-SWCNTs resulted in exposure of hydrophobic patches on erythrocyte membrane that is indicative of membrane damage. A time and dose dependent increase in externalization of phosphatidylserine on erythrocyte membrane bilayer was also found. Administration of AF-SWCNTs through intravenous route resulted in a transient anemia as seen by a sharp decline in blood erythrocyte count accompanied with a significant drop in blood haemoglobin level. Administration of AF-SWCNTs through intratracheal administration also showed significant decline in RBC count while administration through other routes (gavage and intra-peritoneal) was not effective. By using a recently developed technique of a two step in vivo biotinylation of erythrocytes that enables simultaneous enumeration of young (age <10 days) and old (age>40 days) erythrocytes in mouse blood, it was found that the in vivo toxic effect of AF-SWCNTs was more pronounced on older subpopulation of erythrocytes. Subpopulation of old erythrocytes fell after treatment with AF-SWCNTs but recovered by third day after the intravenous administration of AF-SWCNTs. Taken together our results indicate that treatment with AF-SWCNTs results in acute membrane damage and eventual lysis of erythrocytes. Intravenous

  6. Sequestration of Single-Walled Carbon Nanotubes in a Polymer

    NASA Technical Reports Server (NTRS)

    Bley, Richard A.

    2007-01-01

    Sequestration of single-walled carbon nanotubes (SWCNs) in a suitably chosen polymer is under investigation as a means of promoting the dissolution of the nanotubes into epoxies. The purpose of this investigation is to make it possible to utilize SWCNs as the reinforcing fibers in strong, lightweight epoxy-matrix/carbon-fiber composite materials. SWCNs are especially attractive for use as reinforcing fibers because of their stiffness and strength-to-weight ratio: Their Young s modulus has been calculated to be 1.2 TPa, their strength has been calculated to be as much as 100 times that of steel, and their mass density is only one-sixth that of steel. Bare SWCNs cannot be incorporated directly into composite materials of the types envisioned because they are not soluble in epoxies. Heretofore, SWCNS have been rendered soluble by chemically attaching various molecular chains to them, but such chemical attachments compromise their structural integrity. In the method now under investigation, carbon nanotubes are sequestered in molecules of poly(m-phenylenevinylene-co-2,5-dioctyloxy-p-phenylenevinylene) [PmPV]. The strength of the carbon nanotubes is preserved because they are not chemically bonded to the PmPV. This method exploits the tendency of PmPV molecules to wrap themselves around carbon nanotubes: the wrapping occurs partly because there exists a favorable interface between the conjugated face of a nanotube and the conjugated backbone of the polymer and partly because of the helical molecular structure of PmPV. The constituents attached to the polymer backbones (the side chains) render the PmPV-wrapped carbon nanotubes PmPV soluble in organic materials that, in turn, could be used to suspend the carbon nanotubes in epoxy precursors. At present, this method is being optimized: The side chains on the currently available form of PmPV are very nonpolar and unable to react with the epoxy resins and/or hardeners; as a consequence, SWCN/PmPV composites have been

  7. Synthesis and Raman Characterization of Boron Doped Single Walled Carbon Nanotubes (SWNTs)

    NASA Astrophysics Data System (ADS)

    McGuire, K.; Gothard, N.; Gai, P. L.; Chou, S. G.; Dresselhaus, M. S.; Rao, A. M.

    2003-03-01

    Boron-doped SWNTs were prepared by pulsed laser vaporization of carbon targets containing boron with concentrations ranging between 0.5 - 10 at%. As-prepared samples were characterized using Raman spectroscopy and HRTEM measurements. Above a threshold boron concentration of 3 at%, the growth of SWNT bundles ceases due to the low solubility of boron in carbon at ˜1200 ^oC. Interestingly, a few ˜0.5 nm diameter single walled tubes are found, along with nanographitic material in the soot generated from a target with a boron concentration of ˜7 at%. As expected, the intensity of the ˜1350 cm-1 D-band increases with increasing boron concentration due to boron substitution into the honeycomb lattice. Both the radial breathing mode and tangential G- bands were observed in the Raman spectra in samples with <3 at % boron at ˜186 cm-1 and ˜1591 cm-1, respectively. Implications of boron doping in the nanotube shell will be discussed.

  8. Synthesis and Raman Characterization of Boron Doped Single Walled Carbon Nanotubes (SWNTs)

    NASA Astrophysics Data System (ADS)

    McGuire, K.; Gothard, N.; Gai, P. L.; Chao, S. G.; Dresselhaus, M. S.; Rao, A. M.

    2003-11-01

    Boron-doped SWNTs were prepared by pulsed laser vaporization of carbon targets containing boron with concentrations ranging between 0.5 - 10 at%. As-prepared samples were characterized using Raman spectroscopy and HRTEM measurements. Above a threshold boron concentration of 3 at%, the growth of SWNT bundles ceases due to the low solubility of boron in carbon at ˜1200 ^oC. Interestingly, a few ˜0.5 nm diameter single walled tubes are found, along with nanographitic material in the soot generated from a target with a boron concentration of ˜7 at%. As expected, the intensity of the ˜1350 cm-1 D-band increases with increasing boron concentration due to boron substitution into the honeycomb lattice. Both the radial breathing mode and tangential G- bands were observed in the Raman spectra in samples with <3 at % boron at ˜186 cm-1 and ˜1591 cm-1, respectively. Implications of boron doping in the nanotube shell will be discussed.

  9. Contributions of phosphatidylserine-positive platelets and leukocytes and microparticles to hypercoagulable state in gastric cancer patients.

    PubMed

    Yang, Chunfa; Ma, Ruishuang; Jiang, Tao; Cao, Muhua; Zhao, Liangliang; Bi, Yayan; Kou, Junjie; Shi, Jialan; Zou, Xiaoming

    2016-06-01

    Hypercoagulability in gastric cancer is a common complication and a major contributor to poor prognosis. This study aimed to determine procoagulant activity of blood cells and microparticles (MPs) in gastric cancer patients. Phosphatidylserine-positive blood cells and MPs, and their procoagulant properties in particular, were assessed in 48 gastric cancer patients and 35 healthy controls. Phosphatidylserine-positive platelets, leukocytes, and MPs in patients with tumor-node-metastasis stage III/IV gastric cancer were significantly higher than those in stage I/II patients or healthy controls. Moreover, procoagulant activity of platelets, leukocytes, and MPs in stage III/IV patients was significantly increased compared to the controls, as indicated by shorter clotting time, higher intrinsic and extrinsic factor tenase, and prothrombinase complex activity. Interestingly, lactadherin, which competes with factors V and VIII to bind phosphatidylserine, dramatically prolonged clotting time of the cells and MPs by inhibiting factor tenase and prothrombinase complex activity. Although anti-tissue factor antibody significantly attenuated extrinsic tenase complex activity of leukocytes and MPs, it only slightly prolonged clotting times. Meanwhile, treatment with radical resection reduced phosphatidylserine-positive platelets, leukocytes, and MPs, and prolonged the clotting times of the remaining cells and MPs. Our results suggest that phosphatidylserine-positive platelets, leukocytes, and MPs contribute to hypercoagulability and represent a potential therapeutic target to prevent coagulation in patients with stage III/IV gastric cancer. PMID:26700666

  10. Ultrashort single-walled carbon nanotubes in a lipid bilayer as a new nanopore sensor

    PubMed Central

    Liu, Lei; Yang, Chun; Zhao, Kai; Li, Jingyuan; Wu, Hai-Chen

    2013-01-01

    An important issue in nanopore sensing is to construct stable and versatile sensors that can discriminate analytes with minute differences. Here we report a means of creating nanopores that comprise ultrashort single-walled carbon nanotubes inserted into a lipid bilayer. We investigate the ion transport and DNA translocation through single-walled carbon nanotube nanopores and find that our results are fundamentally different from previous studies using much longer single-walled carbon nanotubes. Furthermore, we utilize the new single-walled carbon nanotube nanopores to selectively detect modified 5-hydroxymethylcytosine in single-stranded DNA, which may have implications in screening specific genomic DNA sequences. This new nanopore platform can be integrated with many unique properties of carbon nanotubes and might be useful in molecular sensing such as DNA-damage detection, nanopore DNA sequencing and other nanopore-based applications. PMID:24352224

  11. Synthesis of Single-Walled Carbon Nanotubes in a Glow Discharge Fine Particle Plasma

    SciTech Connect

    Imazato, N.; Imano, M.; Hayashi, Y.

    2008-09-07

    Carbon fine particles were synthesized being negatively charged and confined in a glow discharge plasma. The deposited fine particles were analyzed by Raman spectroscopy and transmission electron microscopy (TEM) and were confirmed to include single-walled carbon nanotubes.

  12. Phototransformation-Induced Aggregation of Functionalized Single-Walled Carbon Nanotubes: The Importance of Amorphous Carbon

    EPA Science Inventory

    Single-walled carbon nanotubes (SWCNTs) with proper functionalization are desirable for applications that require dispersion in aqueous and biological environments, and functionalized SWCNTs also serve as building blocks for conjugation with specific molecules in these applicatio...

  13. Evidence for substitutional boron in doped single-walled carbon nanotubes

    SciTech Connect

    Ayala, P.; Pichler, T.; Reppert, J.; Rao, A. M.; Grobosch, M.; Knupfer, M.

    2010-05-03

    Precise determination of acceptors in the laser ablation grown B doped single-walled carbon nanotubes (SWCNTs) has been elusive. Photoemission spectroscopy finds evidence for subpercent substitutional B in this material, which leads to superconductivity in thin film SWNT samples.

  14. Single-walled carbon nanotubes as a multimodal — thermoacoustic and photoacoustic — contrast agent

    PubMed Central

    Pramanik, Manojit; Swierczewska, Magdalena; Green, Danielle; Sitharaman, Balaji; Wang, Lihong V.

    2009-01-01

    We have developed a novel carbon nanotube-based contrast agent for both thermoacoustic and photoacoustic tomography. In comparison with de-ionized water, single-walled carbon nanotubes exhibited more than two-fold signal enhancement for thermoacoustic tomography at 3 GHz. In comparison with blood, they exhibited more than six-fold signal enhancement for photoacoustic tomography at 1064 nm wavelength. The large contrast enhancement of single-walled carbon nanotubes was further corroborated by tissue phantom imaging studies. PMID:19566311

  15. Exposure of phosphatidylserine on the cell surface.

    PubMed

    Nagata, S; Suzuki, J; Segawa, K; Fujii, T

    2016-06-01

    Phosphatidylserine (PtdSer) is a phospholipid that is abundant in eukaryotic plasma membranes. An ATP-dependent enzyme called flippase normally keeps PtdSer inside the cell, but PtdSer is exposed by the action of scramblase on the cell's surface in biological processes such as apoptosis and platelet activation. Once exposed to the cell surface, PtdSer acts as an 'eat me' signal on dead cells, and creates a scaffold for blood-clotting factors on activated platelets. The molecular identities of the flippase and scramblase that work at plasma membranes have long eluded researchers. Indeed, their identity as well as the mechanism of the PtdSer exposure to the cell surface has only recently been revealed. Here, we describe how PtdSer is exposed in apoptotic cells and in activated platelets, and discuss PtdSer exposure in other biological processes. PMID:26891692

  16. Distribution of single wall carbon nanotubes in the Xenopus laevis embryo after microinjection.

    PubMed

    Holt, Brian D; Shawky, Joseph H; Dahl, Kris Noel; Davidson, Lance A; Islam, Mohammad F

    2016-04-01

    Single wall carbon nanotubes (SWCNTs) are advanced materials with the potential for a myriad of diverse applications, including biological technologies and large-scale usage with the potential for environmental impacts. SWCNTs have been exposed to developing organisms to determine their effects on embryogenesis, and results have been inconsistent arising, in part, from differing material quality, dispersion status, material size, impurity from catalysts and stability. For this study, we utilized highly purified SWCNT samples with short, uniform lengths (145 ± 17 nm) well dispersed in solution. To test high exposure doses, we microinjected > 500 µg ml(-1) SWCNT concentrations into the well-established embryogenesis model, Xenopus laevis, and determined embryo compatibility and subcellular localization during development. SWCNTs localized within cellular progeny of the microinjected cells, but were heterogeneously distributed throughout the target-injected tissue. Co-registering unique Raman spectral intensity of SWCNTs with images of fluorescently labeled subcellular compartments demonstrated that even at regions of highest SWCNT concentration, there were no gross alterations to subcellular microstructures, including filamentous actin, endoplasmic reticulum and vesicles. Furthermore, SWCNTs did not aggregate and localized to the perinuclear subcellular region. Combined, these results suggest that purified and dispersed SWCNTs are not toxic to X. laevis animal cap ectoderm and may be suitable candidate materials for biological applications. PMID:26510384

  17. Spectral triangulation: a 3D method for locating single-walled carbon nanotubes in vivo.

    PubMed

    Lin, Ching-Wei; Bachilo, Sergei M; Vu, Michael; Beckingham, Kathleen M; Bruce Weisman, R

    2016-05-21

    Nanomaterials with luminescence in the short-wave infrared (SWIR) region are of special interest for biological research and medical diagnostics because of favorable tissue transparency and low autofluorescence backgrounds in that region. Single-walled carbon nanotubes (SWCNTs) show well-known sharp SWIR spectral signatures and therefore have potential for noninvasive detection and imaging of cancer tumours, when linked to selective targeting agents such as antibodies. However, such applications face the challenge of sensitively detecting and localizing the source of SWIR emission from inside tissues. A new method, called spectral triangulation, is presented for three dimensional (3D) localization using sparse optical measurements made at the specimen surface. Structurally unsorted SWCNT samples emitting over a range of wavelengths are excited inside tissue phantoms by an LED matrix. The resulting SWIR emission is sampled at points on the surface by a scanning fibre optic probe leading to an InGaAs spectrometer or a spectrally filtered InGaAs avalanche photodiode detector. Because of water absorption, attenuation of the SWCNT fluorescence in tissues is strongly wavelength-dependent. We therefore gauge the SWCNT-probe distance by analysing differential changes in the measured SWCNT emission spectra. SWCNT fluorescence can be clearly detected through at least 20 mm of tissue phantom, and the 3D locations of embedded SWCNT test samples are found with sub-millimeter accuracy at depths up to 10 mm. Our method can also distinguish and locate two embedded SWCNT sources at distinct positions. PMID:27140495

  18. Molecular dynamics simulation of non-covalent single-walled carbon nanotube functionalization with surfactant peptides.

    PubMed

    Barzegar, Abolfazl; Mansouri, Alireza; Azamat, Jafar

    2016-03-01

    Non-covalent functionalized single-walled carbon nanotubes (SWCNTs) with improved solubility and biocompatibility can successfully transfer drugs, DNA, RNA, and proteins into the target cells. Theoretical studies such as molecular docking and molecular dynamics simulations in fully atomistic scale were used to investigate the hydrophobic and aromatic π-π-stacking interaction of designing four novel surfactant peptides for non-covalent functionalization of SWCNTs. The results indicated that the designed peptides have binding affinity towards SWCNT with constant interactions during MD simulation times, and it can even be improved by increasing the number of tryptophan residues. The aromatic content of the peptides plays a significant role in their adsorption in SWCNT wall. The data suggest that π-π stacking interaction between the aromatic rings of tryptophan and π electrons of SWCNTs is more important than hydrophobic effects for dispersing carbon nanotubes; nevertheless SWCNTs are strongly hydrophobic in front of smooth surfaces. The usage of aromatic content of peptides for forming SWCNT/peptide complex was proved successfully, providing new insight into peptide design strategies for future nano-biomedical applications. PMID:26811869

  19. Large scale combustion synthesis of single-walled carbon nanotubes and their characterization.

    PubMed

    Richter, Henning; Treska, Meri; Howard, Jack B; Wen, John Z; Thomasson, Sebastien B; Reading, Arthur A; Jardim, Paula M; Vander Sande, John B

    2008-11-01

    Since its invention in 1991, premixed combustion synthesis of fullerenic materials has been established as the major industrial process for manufacturing of these materials. Large-scale production of fullerenes such as C60, C70 and C84 has been implemented. More recently, combustion technology has been extended to the targeted synthesis of single-walled carbon nanotubes (SWCNT). Addition of catalyst precursor and operation at well-controlled fuel-rich but non-sooting conditions are required. Extensive parametric studies have allowed for the optimization of the formation of high-quality SWCNT. Purification techniques previously reported in the literature have been adjusted and used successfully for the nearly complete removal of metal and metal oxide. Material has been characterized using Raman spectroscopy, scanning (SEM) and transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Correlations between process conditions and nanotube properties such as length have been established. Product reproducibility and process scalability of the combustion process have been demonstrated. Sample preparation was found to affect significantly the apparent characteristics of nanotubes as seen in electron microscopy images. PMID:19198347

  20. Molecular simulation of hydrogen adsorption in single-walled carbon nanotubes and idealized carbon slit pores

    NASA Astrophysics Data System (ADS)

    Wang, Qinyu; Johnson, J. Karl

    1999-01-01

    The adsorption of hydrogen gas into single-walled carbon nanotubes (SWNTs) and idealized carbon slit pores is studied by computer simulation. Hydrogen-hydrogen interactions are modeled with the Silvera-Goldman potential. The Crowell-Brown potential is used to model the hydrogen-carbon interactions. Calculations include adsorption inside the tubes, in the interstitial regions of tube arrays, and on the outside surface of isolated tubes. Quantum effects are included through implementation of the path integral formalism. Comparison with classical simulations gives an indication of the importance of quantum effects for hydrogen adsorption. Quantum effects are important even at 298 K for adsorption in tube interstices. We compare our simulations with experimental data for SWNTs, graphitic nanofibers, and activated carbon. Adsorption isotherms from simulations are in reasonable agreement with experimental data for activated carbon, but do not confirm the large uptake reported for SWNTs and nanofibers. Although the adsorption potential for hydrogen in SWNTs is enhanced relative to slit pores of the same size, our calculations show that the storage capacity of an array of tubes is less than that for idealized slit pore geometries, except at very low pressures. Ambient temperature isotherms indicate that an array of nanotubes is not a suitable sorbent material for achieving DOE targets for vehicular hydrogen storage.

  1. Gas dynamic and time resolved imaging studies of single-wall carbon nanotubes growth in the laser ablation process

    NASA Astrophysics Data System (ADS)

    Sen, Rahul; Suzuki, S.; Kataura, H.; Achiba, Y.

    2001-10-01

    Single-wall carbon nanotubes (SWNTs) were synthesized by laser ablation of Ni-Co-graphite composite targets at 1200 °C under flowing argon. The effects of the temperature gradient near the target and the gas flow rate on the diameter distribution of SWNTs were studied in order to understand their growth dynamics. The diameter distribution of the SWNTs, analyzed by Raman spectroscopy, was dependent on the gas flow rate when there was a temperature gradient around the target. Time resolved scattering images from the ablated species at different flow rates indicated that velocities of backward moving species increased with increasing flow rate. These findings are used to estimate the time required for nucleation and the growth of SWNTs.

  2. Internalization of paramagnetic phosphatidylserine-containing liposomes by macrophages

    PubMed Central

    2012-01-01

    Background Inflammation plays an important role in many pathologies, including cardiovascular diseases, neurological conditions and oncology, and is considered an important predictor for disease progression and outcome. In vivo imaging of inflammatory cells will improve diagnosis and provide a read-out for therapy efficacy. Paramagnetic phosphatidylserine (PS)-containing liposomes were developed for magnetic resonance imaging (MRI) and confocal microscopy imaging of macrophages. These nanoparticles also provide a platform to combine imaging with targeted drug delivery. Results Incorporation of PS into liposomes did not affect liposomal size and morphology up to 12 mol% of PS. Liposomes containing 6 mol% of PS showed the highest uptake by murine macrophages, while only minor uptake was observed in endothelial cells. Uptake of liposomes containing 6 mol% of PS was dependent on the presence of Ca2+ and Mg2+. Furthermore, these 6 mol% PS-containing liposomes were mainly internalized into macrophages, whereas liposomes without PS only bound to the macrophage cell membrane. Conclusions Paramagnetic liposomes containing 6 mol% of PS for MR imaging of macrophages have been developed. In vitro these liposomes showed specific internalization by macrophages. Therefore, these liposomes might be suitable for in vivo visualization of macrophage content and for (visualization of) targeted drug delivery to inflammatory cells. PMID:22929153

  3. Current Progress in the Chemical Vapor Deposition of Type-Selected Horizontally Aligned Single-Walled Carbon Nanotubes.

    PubMed

    Ibrahim, Imad; Gemming, Thomas; Weber, Walter M; Mikolajick, Thomas; Liu, Zhongfan; Rümmeli, Mark H

    2016-08-23

    Exciting electrical properties of single-walled carbon nanotubes show promise as a future class of electronic materials, yet the manufacturing challenges remain significant. The key challenges are to determine fabrication approaches for complex and flexible arrangements of nanotube devices that are reliable, rapid, and reproducible. Realizing regular array structures is an important step toward this goal. Considerable efforts have and are being made in this vein, although the progress to date is somewhat modest. However, there are reasons to be optimistic. Positive steps of being able to control not only the spatial location and diameter of the tubes but also their electronic type (chiral control) are being made. Two primary approaches are being exploited to address the challenges. Tube deposition techniques, on the one hand, and direct growth of the desired tube at the target location are being explored. While this review covers both approaches, the emphasis is on recent developments in the direct fabrication of type-selected horizontally aligned single-walled carbon nanotubes by chemical vapor deposition. PMID:27427780

  4. Analysis of Stress Responsive Genes Induced by Single-Walled Carbon Nanotubes in BJ Foreskin Cells

    PubMed Central

    Sarkar, Shubhashish; Sharma, Chidananda; Yog, Rajeshwari; Periakaruppan, Adaikkappan; Jejelowo, Olufisayo; Thomas, Renard; Barrera, Enrique V.; Rice-Ficht, Allison C.; Wilson, Bobby L.; Ramesh, Govindarajan T.

    2009-01-01

    Nanotechnology is finding its use as a potential technology in consumer products, defense, electronics, and medical applications by exploiting the properties of nanomaterials. Single-walled carbon nanotubes are novel forms of these nanomaterials with potential for large applications. However, the toxicity studies on this material are not explored in detail and therefore limiting its use. It has been earlier reported that single-walled carbon nanotubes induces oxidative stress and also dictates activation of specific signaling pathway in keratinocytes. The present study explores the effect of single-walled carbon nanotubes on stress genes in human BJ Foreskin cells. The results show induction of oxidative stress in BJ Foreskin cells by single-walled carbon nanotubes and increase in stress responsive genes. The genes included inducible genes like HMOX1, HMOX2, and Cyp1B1. In addition we validated increase for four genes by SWCNT, namely ATM, CCNC, DNAJB4, and GADD45A by RT-PCR. Moreover results of the altered stress related genes have been discussed and that partially explains some of the toxic responses induced by single-walled carbon nanotubes. PMID:17450800

  5. Phosphatidylserine and FVa Regulate FXa Structure

    PubMed Central

    Srivasatava, Kinshuk Raj; Majumder, Rinku; Kane, William H.; Quinn-Allen, Mary Ann

    2014-01-01

    Human coagulation factor Xa (FXa) plays a key role in blood coagulation by activating prothrombin to thrombin on “stimulated” platelet membranes in the presence of its cofactor factor Va (FVa). Phosphatidylserine (PS) exposure on activated platelet membranes promotes prothrombin activation by FXa by allosterically regulating FXa. To identify the structural basis of this allosteric regulation, we used fluorescence resonance energy transfer (FRET) to monitor changes in FXa length in response 1] to soluble PS (dicaproyl-phosphatidylserine; C6PS), 2] to PS membranes, and 3] to FVa in the presence of C6PS and membranes. We incorporated a FRET pair with donor (fluorescein) at the active site and acceptor (Alexa fluor 555) at FXa N-terminus near the membrane. The results demonstrated that FXa structure changes upon binding of C6PS to two sites, a regulatory site (Reg site) at the N-terminus (previously identified as involving the Gla and EGFN domains) and a presumptive protein-recognition site in the catalytic domain (Prot site). Binding of C6PS to the regulatory site increased the inter-probe distance by ~ 3 Å, while saturation of both sites further increased the distance by ~ 6.4 Å. FXa binding to a membrane produced a smaller length increase (~1.4 Å), indicating that FXa has a somewhat different structure on a membrane than when bound to C6PS in solution. However, when both FVa2 (a FVa glycoform) and either C6PS or PS-containing membranes bound to FXa, the overall change in length was comparable (~ 5.6–5.8 Å), indicating that C6PS and PS-containing membranes in conjunction with FVa2 have comparable regulatory effects on FXa. We conclude that the similar functional regulation of FXa by C6PS or membranes in conjunction with FVa2 correlates with similar structural regulation. The results demonstrate the usefulness of FRET in analyzing structure-function relationships in FXa and in the FXa.FVa2 complex. PMID:24467409

  6. Review of Laser Ablation Process for Single Wall Carbon Nanotube Production

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivaram

    2003-01-01

    Different types of lasers are now routinely used to prepare single wall carbon nanotubes (SWCNTs). The original method developed by researchers at Rice University utilized a "double pulse laser oven" process. A graphite target containing about 1 atomic percent of metal catalysts is ablated inside a 1473K oven using laser pulses (10 ns pulse width) in slow flowing argon. Two YAG lasers with a green pulse (532 nm) followed by an IR pulse (1064 nm) with a 50 ns delay are used for ablation. This set up produced single wall carbon nanotube material with about 70% purity having a diameter distribution peaked around 1.4 nm. The impurities consist of fullerenes, metal catalyst clusters (10 to 100 nm diameter) and amorphous carbon. The rate of production with the initial set up was about 60 mg per hour with 10Hz laser systems. Several researchers have used variations of the lasers to improve the rate, consistency and study effects of different process parameters on the quality and quantity of SWCNTs. These variations include one to three YAG laser systems (Green, Green and IR), different pulse widths (nano to microseconds as well as continuous) and different laser wavelengths (Alexandrite, CO, CO2, free electron lasers in the near to far infrared). It is noted that yield from the single laser (Green or IR) systems is only a fraction of the two laser systems. The yield seemed to scale up with the repetition rate of the laser systems (10 to 60 Hz) and depended on the beam uniformity and quality of the laser pulses. The shift to longer wavelength lasers (free electron, CO and CO2) did not improve the quality, but increased the rate of production because these lasers are either continuous (CW) or high repetition rate pulses (kHz to MHz). The average power and the peak power of the lasers seem to influence the yields. Very high peak powers (MegaWatts per square centimeter) are noted to increase ablation of bigger particles with reduced yields of SWCNTs. Increased average powers

  7. Dissolution of single-walled carbon nanotubes in alkanol-cholic acid mixtures

    NASA Astrophysics Data System (ADS)

    Dyshin, A. A.; Eliseeva, O. V.; Bondarenko, G. V.; Kiselev, M. G.

    2015-09-01

    A procedure for dispersing the single-walled carbon nanotubes (SWCNTs) for preparing stable suspensions with high concentrations of individual nanotubes in various alcohols was described. The obtained suspensions were studied by Raman spectroscopy. The solubility of the single-walled carbon nanotubes in alcohols was found to depend on the concentration of cholic acid. The ethanol-surfactant mixture was shown to be the best solvent for all alkanol-cholic acid mixtures (0.018 mol/kg) under study used for preparing time-stable suspensions of single-walled carbon nanotubes. The dissolving ability of aliphatic alcohols was found to decrease in the series: ethanol-isopropanol- tert-butanol-butanol-propanol.

  8. Systematic conversion of single walled carbon nanotubes into n-type thermoelectric materials by molecular dopants.

    PubMed

    Nonoguchi, Yoshiyuki; Ohashi, Kenji; Kanazawa, Rui; Ashiba, Koji; Hata, Kenji; Nakagawa, Tetsuya; Adachi, Chihaya; Tanase, Tomoaki; Kawai, Tsuyoshi

    2013-01-01

    Thermoelectrics is a challenging issue for modern and future energy conversion and recovery technology. Carbon nanotubes are promising active thermoelectic materials owing to their narrow bandgap energy and high charge carrier mobility, and they can be integrated into flexible thermoelectrics that can recover any waste heat. We here report air-stable n-type single walled carbon nanotubes with a variety of weak electron donors in the range of HOMO level between ca. -4.4 eV and ca. -5.6 eV, in which partial uphill electron injection from the dopant to the conduction band of single walled carbon nanotubes is dominant. We display flexible films of the doped single walled carbon nanotubes possessing significantly large thermoelectric effect, which is applicable to flexible ambient thermoelectric modules. PMID:24276090

  9. Shape transition of unstrained flattest single-walled carbon nanotubes under pressure

    SciTech Connect

    Mu, Weihua E-mail: muwh@itp.ac.cn; Cao, Jianshu; Ou-Yang, Zhong-can

    2014-01-28

    Single walled carbon nanotube's (SWCNT's) cross section can be flattened under hydrostatic pressure. One example is the cross section of a single walled carbon nanotube successively deforms from the original round shape to oval shape, then to peanut-like shape. At the transition point of reversible deformation between convex shape and concave shape, the side wall of nanotube is flattest. This flattest tube has many attractive properties. In the present work, an approximate approach is developed to determine the equilibrium shape of this unstrained flattest tube and the curvature distribution of this tube. Our results are in good agreement with recent numerical results, and can be applied to the study of pressure controlled electric properties of single walled carbon nanotubes. The present method can also be used to study other deformed inorganic and organic tube-like structures.

  10. Continuous growth of single-wall carbon nanotubes using chemical vapor deposition

    DOEpatents

    Grigorian, Leonid; Hornyak, Louis; Dillon, Anne C; Heben, Michael J

    2014-09-23

    The invention relates to a chemical vapor deposition process for the continuous growth of a carbon single-wall nanotube where a carbon-containing gas composition is contacted with a porous membrane and decomposed in the presence of a catalyst to grow single-wall carbon nanotube material. A pressure differential exists across the porous membrane such that the pressure on one side of the membrane is less than that on the other side of the membrane. The single-wall carbon nanotube growth may occur predominately on the low-pressure side of the membrane or, in a different embodiment of the invention, may occur predominately in between the catalyst and the membrane. The invention also relates to an apparatus used with the carbon vapor deposition process.

  11. Continuous growth of single-wall carbon nanotubes using chemical vapor deposition

    DOEpatents

    Grigorian, Leonid; Hornyak, Louis; Dillon, Anne C; Heben, Michael J

    2008-10-07

    The invention relates to a chemical vapor deposition process for the continuous growth of a carbon single-wall nanotube where a carbon-containing gas composition is contacted with a porous membrane and decomposed in the presence of a catalyst to grow single-wall carbon nanotube material. A pressure differential exists across the porous membrane such that the pressure on one side of the membrane is less than that on the other side of the membrane. The single-wall carbon nanotube growth may occur predominately on the low-pressure side of the membrane or, in a different embodiment of the invention, may occur predominately in between the catalyst and the membrane. The invention also relates to an apparatus used with the carbon vapor deposition process.

  12. Phosphatidylserine exposure is required for ADAM17 sheddase function

    PubMed Central

    Sommer, Anselm; Kordowski, Felix; Büch, Joscha; Maretzky, Thorsten; Evers, Astrid; Andrä, Jörg; Düsterhöft, Stefan; Michalek, Matthias; Lorenzen, Inken; Somasundaram, Prasath; Tholey, Andreas; Sönnichsen, Frank D.; Kunzelmann, Karl; Heinbockel, Lena; Nehls, Christian; Gutsmann, Thomas; Grötzinger, Joachim; Bhakdi, Sucharit; Reiss, Karina

    2016-01-01

    ADAM17, a prominent member of the ‘Disintegrin and Metalloproteinase' (ADAM) family, controls vital cellular functions through cleavage of transmembrane substrates. Here we present evidence that surface exposure of phosphatidylserine (PS) is pivotal for ADAM17 to exert sheddase activity. PS exposure is tightly coupled to substrate shedding provoked by diverse ADAM17 activators. PS dependency is demonstrated in the following: (a) in Raji cells undergoing apoptosis; (b) in mutant PSA-3 cells with manipulatable PS content; and (c) in Scott syndrome lymphocytes genetically defunct in their capacity to externalize PS in response to intracellular Ca2+ elevation. Soluble phosphorylserine but not phosphorylcholine inhibits substrate cleavage. The isolated membrane proximal domain (MPD) of ADAM17 binds to PS but not to phosphatidylcholine liposomes. A cationic PS-binding motif is identified in this domain, replacement of which abrogates liposome-binding and renders the protease incapable of cleaving its substrates in cells. We speculate that surface-exposed PS directs the protease to its targets where it then executes its shedding function. PMID:27161080

  13. Phosphatidylserine exposure is required for ADAM17 sheddase function.

    PubMed

    Sommer, Anselm; Kordowski, Felix; Büch, Joscha; Maretzky, Thorsten; Evers, Astrid; Andrä, Jörg; Düsterhöft, Stefan; Michalek, Matthias; Lorenzen, Inken; Somasundaram, Prasath; Tholey, Andreas; Sönnichsen, Frank D; Kunzelmann, Karl; Heinbockel, Lena; Nehls, Christian; Gutsmann, Thomas; Grötzinger, Joachim; Bhakdi, Sucharit; Reiss, Karina

    2016-01-01

    ADAM17, a prominent member of the 'Disintegrin and Metalloproteinase' (ADAM) family, controls vital cellular functions through cleavage of transmembrane substrates. Here we present evidence that surface exposure of phosphatidylserine (PS) is pivotal for ADAM17 to exert sheddase activity. PS exposure is tightly coupled to substrate shedding provoked by diverse ADAM17 activators. PS dependency is demonstrated in the following: (a) in Raji cells undergoing apoptosis; (b) in mutant PSA-3 cells with manipulatable PS content; and (c) in Scott syndrome lymphocytes genetically defunct in their capacity to externalize PS in response to intracellular Ca(2+) elevation. Soluble phosphorylserine but not phosphorylcholine inhibits substrate cleavage. The isolated membrane proximal domain (MPD) of ADAM17 binds to PS but not to phosphatidylcholine liposomes. A cationic PS-binding motif is identified in this domain, replacement of which abrogates liposome-binding and renders the protease incapable of cleaving its substrates in cells. We speculate that surface-exposed PS directs the protease to its targets where it then executes its shedding function. PMID:27161080

  14. Spectral triangulation: a 3D method for locating single-walled carbon nanotubes in vivo

    NASA Astrophysics Data System (ADS)

    Lin, Ching-Wei; Bachilo, Sergei M.; Vu, Michael; Beckingham, Kathleen M.; Bruce Weisman, R.

    2016-05-01

    Nanomaterials with luminescence in the short-wave infrared (SWIR) region are of special interest for biological research and medical diagnostics because of favorable tissue transparency and low autofluorescence backgrounds in that region. Single-walled carbon nanotubes (SWCNTs) show well-known sharp SWIR spectral signatures and therefore have potential for noninvasive detection and imaging of cancer tumours, when linked to selective targeting agents such as antibodies. However, such applications face the challenge of sensitively detecting and localizing the source of SWIR emission from inside tissues. A new method, called spectral triangulation, is presented for three dimensional (3D) localization using sparse optical measurements made at the specimen surface. Structurally unsorted SWCNT samples emitting over a range of wavelengths are excited inside tissue phantoms by an LED matrix. The resulting SWIR emission is sampled at points on the surface by a scanning fibre optic probe leading to an InGaAs spectrometer or a spectrally filtered InGaAs avalanche photodiode detector. Because of water absorption, attenuation of the SWCNT fluorescence in tissues is strongly wavelength-dependent. We therefore gauge the SWCNT-probe distance by analysing differential changes in the measured SWCNT emission spectra. SWCNT fluorescence can be clearly detected through at least 20 mm of tissue phantom, and the 3D locations of embedded SWCNT test samples are found with sub-millimeter accuracy at depths up to 10 mm. Our method can also distinguish and locate two embedded SWCNT sources at distinct positions.Nanomaterials with luminescence in the short-wave infrared (SWIR) region are of special interest for biological research and medical diagnostics because of favorable tissue transparency and low autofluorescence backgrounds in that region. Single-walled carbon nanotubes (SWCNTs) show well-known sharp SWIR spectral signatures and therefore have potential for noninvasive detection and

  15. Investigation on vibration of single-walled carbon nanotubes by variational iteration method

    NASA Astrophysics Data System (ADS)

    Ahmadi Asoor, A. A.; Valipour, P.; Ghasemi, S. E.

    2016-02-01

    In this paper, the variational iteration method (VIM) has been used to investigate the non-linear vibration of single-walled carbon nanotubes (SWCNTs) based on the nonlocal Timoshenko beam theory. The accuracy of results is examined by the fourth-order Runge-Kutta numerical method. Comparison between VIM solutions with numerical results leads to highly accurate solutions. Also, the behavior of deflection and frequency in vibrations of SWCNTs are studied. The results show that frequency of single walled carbon nanotube versus amplitude increases by increasing the values of B.

  16. Free vibration analysis of fluid-conveying single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Reddy, C. D.; Lu, C.; Rajendran, S.; Liew, K. M.

    2007-03-01

    The effect of fluid flow on the free vibration and instability of fluid-conveying single-walled carbon nanotubes is studied. The possibility of developing a technique to measure the mass flow rate of fluid is examined. Atomistic simulations and the continuum beam model are used. Simulations are performed to quantify the inertial, stiffness, Coriolis, and centrifugal forces generated by flow during the free vibration. A numerical expression is developed to measure the mass flow rate of the fluid velocities up to 40% of the critical flow velocity. This observation is useful to quantify the mass flow measurement of fluid conveying single-walled carbon nanotubes.

  17. Collision-induced fusion of two single-walled carbon nanotubes: A quantitative study

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Mao, Fei; Meng, Xiang-Rui; Wang, Dong-Qi; Zhang, Feng-Shou

    2016-07-01

    The coalescence processes of two (6, 0) single-walled carbon nanotubes are investigated via coaxial collision based on the self-consistent-charge density-functional tight-binding molecular dynamics method. According to the structure characteristics of the nanotubes, five impact cases are studied to explore the coalescence processes of the nanotubes. The simulation shows that various kinds of carbon nanomaterials, such as graphene sheets, graphene nanoribbons, and single-walled carbon nanotubes with larger diameters, are created after collision. Moreover, some defects formed in the carbon nanomaterials can be eliminated, and even the final configurations which are originally fragmented can almost become intact structures by properly quenching and annealing.

  18. Molecular dynamics study of electron-irradiation effects in single-walled carbon nanotubes

    SciTech Connect

    Yasuda, Masaaki; Kimoto, Yoshihisa; Tada, Kazuhiro; Mori, Hideki; Akita, Seiji; Hirai, Yoshihiko; Nakayama, Yoshikazu

    2007-05-15

    Molecular dynamics studies are carried out to investigate electron-irradiation effects in single-walled carbon nanotubes. We have proposed a simulation model which includes the interaction between a high-energy incident electron and a carbon atom, based on Monte Carlo method using the elastic-scattering cross section. The atomic level behavior of a single-walled carbon nanotube under electron irradiation is demonstrated in nanosecond time scale. The incident electron energy, tube diameter, and tube temperature dependences of electron-irradiation effects are studied with the simulation.

  19. Bolometric detector on the basis of single-wall carbon nanotube/polymer composite

    NASA Astrophysics Data System (ADS)

    Aliev, Ali E.

    2008-10-01

    Infrared imaging sensors that operate without cryogenic cooling have the potential to provide the military or civilian users with infrared vision capabilities packaged in a camera of extremely small size, weight and power consumption. We present here the uncooled bolometric sensor on the basis of single-walled carbon nanotubes (SWNTs) polymer composite with enhanced sensitivity. The voltage responsivity of device working at room temperatures exceeds 150 V/W. The absorption coefficient of single-wall carbon nanotubes was increased by involving Forster type energy transfer from polymer film to dispersed SWNT. The temperature gradient of resistivity was substantially improved by chemical functionalization of SWNT.

  20. Limits of the PECVD process for single wall carbon nanotubes growth

    NASA Astrophysics Data System (ADS)

    Gohier, A.; Minea, T. M.; Djouadi, A. M.; Granier, A.; Dubosc, M.

    2006-04-01

    This Letter explores the capabilities of plasma enhanced chemical vapor deposition to grow vertical oriented single wall, double wall or multi walled carbon nanotubes (CNTs). Our dual process uses high-density low-pressure plasma excited by electron cyclotron resonance using acetylene diluted in ammonia. The early stages of CNTs synthesis have been probed taking advantage of the low growth rate of our process. Two antagonist effects have been shown up: the formation of catalyzed carbon nanotubes against ion assisted bonds breaking. The limits of plasma single wall CNTs growth are discussed and transitory stages have been revealed for the first time.

  1. Dispersion of Single Wall Carbon Nanotubes by in situ Polymerization Under Sonication

    NASA Technical Reports Server (NTRS)

    Park, Cheol; Ounaies, Zoubeida; Watson, Kent A.; Crooks, Roy E.; Smith, Joseph, Jr.; Lowther, Sharon E.; Connell, John W.; Siochi, Emilie J.; Harrison, Joycelyn S.; St.Clair, Terry L.

    2002-01-01

    Single wall nanotube reinforced polyimide nanocomposites were synthesized by in situ polymerization of monomers of interest in the presence of sonication. This process enabled uniform dispersion of single wall carbon nanotube (SWNT) bundles in the polymer matrix. The resultant SWNT-polyimide nanocomposite films were electrically conductive (antistatic) and optically transparent with significant conductivity enhancement (10 orders of magnitude) at a very low loading (0.1 vol%). Mechanical properties as well as thermal stability were also improved with the incorporation of the SWNT.

  2. Heat-induced transformations in coronene-single-walled carbon nanotube systems

    NASA Astrophysics Data System (ADS)

    Chernov, Alexander I.; Fedotov, Pavel V.; Krylov, Alexander S.; Vtyurin, Alexander N.; Obraztsova, Elena D.

    2016-03-01

    Coronene molecules are used as filler for single-walled carbon nanotubes. Variation of the synthesis temperature regimes leads to formation of different types of carbon nanostructures inside the nanotubes. Accurate determination of the structures by optical spectroscopy methods remains an important issue in composite materials. Clear distinction between adsorbed organic molecules on the surface of the tubes and filled structures may be accessed by Raman and photoluminescence spectroscopies. We perform additional heat treatment after the initial synthesis procedure and show the evolution of the optical spectral features corresponding to the filled structures and adsorbed materials on the surface of single-walled carbon nanotubes.

  3. Process for separating metallic from semiconducting single-walled carbon nanotubes

    NASA Technical Reports Server (NTRS)

    Sun, Ya-Ping (Inventor)

    2008-01-01

    A method for separating semiconducting single-walled carbon nanotubes from metallic single-walled carbon nanotubes is disclosed. The method utilizes separation agents that preferentially associate with semiconducting nanotubes due to the electrical nature of the nanotubes. The separation agents are those that have a planar orientation, .pi.-electrons available for association with the surface of the nanotubes, and also include a soluble portion of the molecule. Following preferential association of the separation agent with the semiconducting nanotubes, the agent/nanotubes complex is soluble and can be solubilized with the solution enriched in semiconducting nanotubes while the residual solid is enriched in metallic nanotubes.

  4. Temperature threshold and water role in CVD growth of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Geng, Junfeng; Motta, Marcelo; Angels, Volker; Luo, Jikui; Johnson, Brian

    2016-02-01

    An in-depth understanding of the growth process of single walled carbon nanotubes is of vital importance to the control of the yield of the material and its carbon structure. Using a nickel/silica (Ni/SiOx) catalyst we have conducted a series of growth experiments with a chemical vapour deposition (CVD) system. We find that there is a temperature threshold in the CVD process, and if the reaction temperature sets above this threshold there will be no growth of the nanotubes. In association with this temperature effect, water plays an important role in the promotion or termination of the growth of single walled carbon nanotubes.

  5. Single-walled carbon nanotube growth from ion implanted Fe catalyst

    SciTech Connect

    Choi, Yongho; Sippel-Oakley, Jennifer; Ural, Ant

    2006-10-09

    The authors present experimental evidence that single-walled carbon nanotubes can be grown by chemical vapor deposition from ion implanted iron catalyst. They systematically characterize the effect of ion implantation dose and energy on the catalyst nanoparticles and nanotubes formed at 900 deg. C. They also fabricate a micromachined silicon grid for direct transmission electron microscopy characterization of the as-grown nanotubes. This work opens up the possibility of controlling the origin of single-walled nanotubes at the nanometer scale and of integrating them into nonplanar three-dimensional device structures with precise dose control.

  6. Development of new techniques for functionalizing single-wall carbon nanotubes for composite and biological systems

    NASA Astrophysics Data System (ADS)

    Hudson, Jared Lee

    Building from established methods of using diazonium salts to derivatize single-wall carbon nanotubes (SWNTs), new methodologies for achieving functionalized individual nanotubes that are compatible with a wide variety of materials have been developed. The use of aryl triazenes as diazonium precursors to functionalize surfactant stabilized suspensions of individual SWNTs has resulted in the ability to synthesize more complex molecules bearing a diazonium salt precursor. Prior to this work, such functionality was difficult to install in complex molecules due to the required linearity of diazonium salt synthesis. A protocol to access individualized SWNTs without the use of scale-limiting techniques such as high powered sonication and centrifugation was achieved by the use of oleum as a solvent for underivatized SWNTs. This disentangled suspension of SWNTs was then treated with a modification of an established in-situ diazonium functionalization protocol to yield alcohol and water-soluble, exfoliated, nonroping SWNTs. Functionalized SWNTs were used as polymerization initiators for both anionic and atom transfer radical polymerization. They were used to reinforce poly(dimethylsiloxane) and poly(propylene fumarate) based composites. The functionalized SWNTs were also used as a support for neuronal interface systems and to reinforce the collagen network in rat cervical tissue. Through continued functionalization and PEGylation (poly(ethylene glycol) attachment) of cut SWNTs, the development of a SWNT-based, viable nanovector core has been achieved. Continued functionalization provides one with the ability to further derivatize aqueous suspensions of previously functionalized SWNTs, while the PEGylation of cut SWNTs offers solubility in water, irrigation saline, and phosphate buffered saline. Using the developed SWNT-based nanovector core, molecules that are relevant for attachment to a nanovector were targeted. This includes a fluorescein-5-isothiocyanate (FITC

  7. Single Walled Carbon Nanotube-Based Junction Biosensor for Detection of Escherichia coli

    PubMed Central

    Yamada, Kara; Kim, Chong-Tai; Kim, Jong-Hoon; Chung, Jae-Hyun; Lee, Hyeon Gyu; Jun, Soojin

    2014-01-01

    Foodborne pathogen detection using biomolecules and nanomaterials may lead to platforms for rapid and simple electronic biosensing. Integration of single walled carbon nanotubes (SWCNTs) and immobilized antibodies into a disposable bio-nano combinatorial junction sensor was fabricated for detection of Escherichia coli K-12. Gold tungsten wires (50 µm diameter) coated with polyethylenimine (PEI) and SWCNTs were aligned to form a crossbar junction, which was functionalized with streptavidin and biotinylated antibodies to allow for enhanced specificity towards targeted microbes. In this study, changes in electrical current (ΔI) after bioaffinity reactions between bacterial cells (E. coli K-12) and antibodies on the SWCNT surface were monitored to evaluate the sensor's performance. The averaged ΔI increased from 33.13 nA to 290.9 nA with the presence of SWCNTs in a 108 CFU/mL concentration of E. coli, thus showing an improvement in sensing magnitude. Electrical current measurements demonstrated a linear relationship (R2 = 0.973) between the changes in current and concentrations of bacterial suspension in range of 102–105 CFU/mL. Current decreased as cell concentrations increased, due to increased bacterial resistance on the bio-nano modified surface. The detection limit of the developed sensor was 102 CFU/mL with a detection time of less than 5 min with nanotubes. Therefore, the fabricated disposable junction biosensor with a functionalized SWCNT platform shows potential for high-performance biosensing and application as a detection device for foodborne pathogens. PMID:25233366

  8. Ab initio computational investigation of physisorption of molecular hydrogen on achiral single-walled carbon nanotubes.

    PubMed

    Ferre-Vilaplana, A

    2005-06-01

    Using relatively approximated methods, physisorption of molecular hydrogen on single-walled carbon nanotubes (SWCNTs) as a mechanism to develop hydrogen storage systems has been only partially investigated in literature. Here, we use ab initio molecular-orbital theory, at benchmark quality level, to provide a more complete description about the mentioned mechanism. Physisorption inside and outside achiral-armchair and zigzag-SWCNTs, in the range of diameters from about 6 A-chiral vectors (5,5) and (8,0)-to more than 30 A-chiral vectors (30,30) and (40,0)-was examined. Perpendicular, longitudinal, and transversal configurations, with the hydrogen molecule centered on an aromatic ring, were taken into account. SWCNTs were modeled as curved coronenelike (C24H12) graphene sheets. Local modeling strategies, using more complete basis sets for the adsorbate and for the nearest atoms to the adsorbate than for the lion's share of the substrate, at the Moller-Plesset second-order correlation level, were selected for numerical treatment. Basis-set superposition errors were corrected by means of the counterpoise method of Bois and Bernardi. It was found that physisorption of molecular hydrogen on SWCNTs would depend mainly on the diameter being virtually independent of the chirality. Lowest physisorption energies, up to 20% less than that on planar graphene, would be reached outside nanotubes in the range of diameters of 6-10 A. For hydrogen storage purposes, highest physisorption energies, up to 40% greater than that on planar graphene, but not more, would be reached inside nanotubes in the relatively narrow range of diameters of 10-20 A. Finally, for diameters from 20 A onwards physisorption of molecular hydrogen on SWCNTs would be in the range of +/-10% of that on planar graphene. To our knowledge, this would be the most complete and realistic theoretical investigation of the target physisorption mechanism to date. PMID:15974779

  9. Oxidative lipidomics of γ-radiation-induced lung injury: mass spectrometric characterization of cardiolipin and phosphatidylserine peroxidation.

    PubMed

    Tyurina, Yulia Y; Tyurin, Vladimir A; Kapralova, Valentyna I; Wasserloos, Karla; Mosher, Mackenzie; Epperly, Michael W; Greenberger, Joel S; Pitt, Bruce R; Kagan, Valerian E

    2011-05-01

    Oxidative damage plays a significant role in the pathogenesis of γ-radiation-induced lung injury. Endothelium is a preferred target for early radiation-induced damage and apoptosis. Given the newly discovered role of oxidized phospholipids in apoptotic signaling, we performed oxidative lipidomics analysis of phospholipids in irradiated mouse lungs and cultured mouse lung endothelial cells. C57BL/6NHsd female mice were subjected to total-body irradiation (10 Gy, 15 Gy) and euthanized 24 h thereafter. Mouse lung endothelial cells were analyzed 48 h after γ irradiation (15 Gy). We found that radiation-induced apoptosis in vivo and in vitro was accompanied by non-random oxidation of phospholipids. Cardiolipin and phosphatidylserine were the major oxidized phospholipids, while more abundant phospholipids (phosphatidylcholine, phosphatidylethanolamine) remained non-oxidized. Electrospray ionization mass spectrometry analysis revealed the formation of cardiolipin and phosphatidylserine oxygenated molecular species in the irradiated lung and cells. Analysis of fatty acids after hydrolysis of cardiolipin and phosphatidylserine by phospholipase A(2) revealed the presence of mono-hydroperoxy and/or mono-hydroxy/mono-epoxy, mono-hydroperoxy/mono-oxo molecular species of linoleic acid. We speculate that cyt c-driven oxidations of cardiolipin and phosphatidylserine associated with the execution of apoptosis in pulmonary endothelial cells are important contributors to endothelium dysfunction in γ-radiation-induced lung injury. PMID:21338246

  10. Oxidative Lipidomics of γ-Radiation-Induced Lung Injury: Mass Spectrometric Characterization of Cardiolipin and Phosphatidylserine Peroxidation

    PubMed Central

    Tyurina, Yulia Y.; Tyurin, Vladimir A.; Kapralova, Valentyna I.; Wasserloos, Karla; Mosher, Mackenzie; Epperly, Michael W.; Greenberger, Joel S.; Pitt, Bruce R.; Kagan, Valerian E.

    2011-01-01

    Oxidative damage plays a significant role in the pathogenesis of γ-radiation-induced lung injury. Endothelium is a preferred target for early radiation-induced damage and apoptosis. Given the newly discovered role of oxidized phospholipids in apoptotic signaling, we performed oxidative lipidomics analysis of phospholipids in irradiated mouse lungs and cultured mouse lung endothelial cells. C57BL/6NHsd female mice were subjected to total-body irradiation (10 Gy, 15 Gy) and euthanized 24 h thereafter. Mouse lung endothelial cells were analyzed 48 h after γ irradiation (15 Gy). We found that radiation-induced apoptosis in vivo and in vitro was accompanied by non-random oxidation of phospholipids. Cardiolipin and phosphatidylserine were the major oxidized phospholipids, while more abundant phospholipids (phosphatidylcholine, phosphatidylethanolamine) remained non-oxidized. Electrospray ionization mass spectrometry analysis revealed the formation of cardiolipin and phosphatidylserine oxygenated molecular species in the irradiated lung and cells. Analysis of fatty acids after hydrolysis of cardiolipin and phosphatidylserine by phospholipase A2 revealed the presence of mono-hydroperoxy and/or mono-hydroxy/mono-epoxy, mono-hydroperoxy/mono-oxo molecular species of linoleic acid. We speculate that cyt c-driven oxidations of cardiolipin and phosphatidylserine associated with the execution of apoptosis in pulmonary endothelial cells are important contributors to endothelium dysfunction in γ-radiation-induced lung injury. PMID:21338246

  11. Simultaneous Determination of Parathion, Malathion, Diazinon, and Pirimiphos Methyl in Dried Medicinal Plants Using Solid-Phase Microextraction Fibre Coated with Single-Walled Carbon Nanotubes

    PubMed Central

    Ahmadkhaniha, Reza; Samadi, Nasrin; Salimi, Mona; Sarkhail, Parisa; Rastkari, Noushin

    2012-01-01

    A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new solid-phase microextraction adsorbent. The developed method showed good performance. For diazinon and pirimiphos methyl calibration, curves were linear (r2 ≥ 0.993) over the concentration ranges from 1.5 to 300 ng g−1, and the limit of detection at signal-to-noise ratio of 3 was 0.3 ng g−1. For parathion and malathion, the linear range and limit of detection were 2.5–300 (r2 ≥ 0.991) and 0.5 ng g−1, respectively. In addition, a comparative study between the single-walled carbon nanotubes and a commercial polydimethylsiloxane fibre for the determination of target analytes was carried out. Single-walled carbon nanotubes fibre showed higher extraction capacity, better thermal stability (over 350°C), and longer lifespan (over 250 times) than the commercial polydimethylsiloxane fibre. The developed method was successfully applied to determine target organophosphorus pesticides in real samples. PMID:22645439

  12. Single-walled carbon nanotube and graphene nanodelivery of gambogic acid increases its cytotoxicity in breast and pancreatic cancer cells

    PubMed Central

    Saeed, Lamya M; Mahmood, Meena; Pyrek, Sebastian J.; Fahmi, Tariq; Xu, Yang; Mustafa, Thikra; Nima, Zeid A.; Bratton, Stacie M.; Casciano, Dan; Dervishi, Enkeleda; Radominska-Pandya, Anna; Biris, Alexandru S.

    2015-01-01

    Graphene and single-walled carbon nanotubes were used to deliver the natural low-toxicity drug gambogic acid (GA) to breast and pancreatic cancer cells in vitro, and the effectiveness of this complex in suppressing cellular integrity was assessed. Cytotoxicity was assessed by measuring lactate dehydrogenase release, mitochondria dehydrogenase activity, mitochondrial membrane depolarization, DNA fragmentation, intracellular lipid content, and membrane permeability/caspase activity. The nanomaterials showed no toxicity at the concentrations used, and the antiproliferative effects of GA were significantly enhanced by nanodelivery. The results suggest that these complexes inhibit human breast and pancreatic cancer cells grown in vitro. This analysis represents a first step toward assessing their effectiveness in more complex, targeted, nanodelivery systems. PMID:25220893

  13. Conducting polymer functionalized single-walled carbon nanotube based chemiresistive biosensor for the detection of human cardiac myoglobin

    SciTech Connect

    Puri, Nidhi; Niazi, Asad; Biradar, Ashok M.; Rajesh E-mail: adani@engr.ucr.edu; Mulchandani, Ashok E-mail: adani@engr.ucr.edu

    2014-10-13

    We report the fabrication of a single-walled carbon nanotube (SWNT) based ultrasensitive label-free chemiresistive biosensor for the detection of human cardiac biomarker, myoglobin (Ag-cMb). Poly(pyrrole-co-pyrrolepropylic acid) with pendant carboxyl groups was electrochemically deposited on electrophoretically aligned SWNT channel, as a conducting linker, for biomolecular immobilization of highly specific cardiac myoglobin antibody. The device was characterized by scanning electron microscopy, source-drain current-voltage (I-V), and charge-transfer characteristic studies. The device exhibited a linear response with a change in conductance in SWNT channel towards the target, Ag-cMb, over the concentration range of 1.0 to 1000 ng ml{sup −1} with a sensitivity of ∼118% per decade with high specificity.

  14. Growth of semiconducting single-wall carbon nanotubes with a narrow band-gap distribution

    PubMed Central

    Zhang, Feng; Hou, Peng-Xiang; Liu, Chang; Wang, Bing-Wei; Jiang, Hua; Chen, Mao-Lin; Sun, Dong-Ming; Li, Jin-Cheng; Cong, Hong-Tao; Kauppinen, Esko I.; Cheng, Hui-Ming

    2016-01-01

    The growth of high-quality semiconducting single-wall carbon nanotubes with a narrow band-gap distribution is crucial for the fabrication of high-performance electronic devices. However, the single-wall carbon nanotubes grown from traditional metal catalysts usually have diversified structures and properties. Here we design and prepare an acorn-like, partially carbon-coated cobalt nanoparticle catalyst with a uniform size and structure by the thermal reduction of a [Co(CN)6]3− precursor adsorbed on a self-assembled block copolymer nanodomain. The inner cobalt nanoparticle functions as active catalytic phase for carbon nanotube growth, whereas the outer carbon layer prevents the aggregation of cobalt nanoparticles and ensures a perpendicular growth mode. The grown single-wall carbon nanotubes have a very narrow diameter distribution centred at 1.7 nm and a high semiconducting content of >95%. These semiconducting single-wall carbon nanotubes have a very small band-gap difference of ∼0.08 eV and show excellent thin-film transistor performance. PMID:27025784

  15. Aqueous-phase synthesis of monodisperse plasmonic gold nanocrystals using shortened single-walled carbon nanotubes.

    PubMed

    Kim, Jin-Woo; Moon, Hyung-Mo; Benamara, Mourad; Sakon, Joshua; Salamo, Gregory J; Zharov, Vladimir P

    2010-10-14

    Monodisperse gold nanocrystals with unique near-infrared optical properties were synthesized by simple mixing of highly shortened and well disperse single-walled carbon nanotubes and chloroauric acid in water at ambient conditions with a step-wise increase of gold ion concentration. PMID:20737105

  16. Chirality sensitive binding of tryptophan enantiomers with pristine single wall carbon nanotubes.

    PubMed

    Bhattacharyya, Tamoghna; Roy, Sarita; Dasgupta, Anjan Kr

    2014-07-28

    We report the differential binding nature of pristine single wall carbon nanotubes (SWNTs) with tryptophan enantiomers. The differential co-operative response between the pristine SWNTs (topologically chiral) and L- and D-tryptophan (geometrically chiral) provides the insight that geometrical chirality itself manifests with topological chirality in a complex way. PMID:24921981

  17. One-step synthesis of fluorescently labelled, single-walled carbon nanotubes.

    PubMed

    Guaragno, Michelle L; Gottardi, Riccardo; Fedorchak, Morgan V; Roy, Abhijit; Kumta, Prashant N; Little, Steven R

    2015-12-18

    Single-walled carbon nanotubes (SWNTs) can be labelled with functional moieties that endow them with a number of unique characteristics, which can be applicable to biomedical applications such as imaging. Herein we describe a facile, one-step esterification process to functionalize SWNT with fluorescein. PMID:26458421

  18. MICROWAVE-INDUCED RAPID CHEMICAL FUNCTIONALIZATION OF SINGLE-WALLED CARBON NANOTUBES (R830901)

    EPA Science Inventory


    Abstract

    The microwave-induced chemical functionalization of single-walled carbon nanotubes (SWNTs) is reported. The major advantage of this high-energy procedure is that it reduced the reaction time to the order of minutes and the number of steps in the reac...

  19. Aggregation Kinetics and Transport of Single-Walled CarbonNanotubes at Low Surfactant Concentrations

    EPA Science Inventory

    Little is known about how low levels of surfactants can affect the colloidal stability of single-walled carbon nanotubes (SWNTs) and how surfactant-wrapping of SWNTs can impact ecological exposures in aqueous systems. In this study, SWNTs were suspended in water with sodium ...

  20. Environmental Detection of Single-Walled Carbon Nanotubes Utilizing Near-Infrared Fluorescence

    EPA Science Inventory

    There are a growing number of applications for carbon nanotubes (CNT) in modern technologies and, subsequently, growth in production of CNT has expanded rapidly. Single-walled CNT (SWCNT) consist of a graphene sheet rolled up into a tube. With growing manufacture and use, the ...

  1. On the Likelihood of Single-Walled Carbon Nanotubes Causing Adverse Marine Ecological Effects

    EPA Science Inventory

    This brief article discusses the ecological effects of single-walled carbon nanotubes (SWNTs)in the marine environment. Based on new research and a review of the scientific literature, the paper concludes that SWNTs are unlikely to cause adverse ecological effects in the marine ...

  2. Engineered Carbohydrate-Binding Module (CBM) Protein-Suspended Single-Walled Carbon Nanotubes in Water

    SciTech Connect

    Xu,Q.; Song, Q.; Ai, X.; McDonald, T. J.; Long, H.; Ding. S. Y.; Himmel, M. E.; Rumbles, G.

    2009-01-01

    Engineered protein, CtCBM4, the first carbohydrate-binding module (CBM) protein is successfully used to debundle and suspend single-walled carbon nanotubes (SWNTs) effectively in aqueous solution, which opens up a new avenue in further functionalizing and potential selectively fractionating SWNTs for diverse biology- and/or energy-related applications.

  3. Production of vertical arrays of small diameter single-walled carbon nanotubes

    DOEpatents

    Hauge, Robert H; Xu, Ya-Qiong

    2013-08-13

    A hot filament chemical vapor deposition method has been developed to grow at least one vertical single-walled carbon nanotube (SWNT). In general, various embodiments of the present invention disclose novel processes for growing and/or producing enhanced nanotube carpets with decreased diameters as compared to the prior art.

  4. Delivering Single-Walled Carbon Nanotubes to the Nucleus Using Engineered Nuclear Protein Domains.

    PubMed

    Boyer, Patrick D; Ganesh, Sairaam; Qin, Zhao; Holt, Brian D; Buehler, Markus J; Islam, Mohammad F; Dahl, Kris Noel

    2016-02-10

    Single-walled carbon nanotubes (SWCNTs) have great potential for cell-based therapies due to their unique intrinsic optical and physical characteristics. Consequently, broad classes of dispersants have been identified that individually suspend SWCNTs in water and cell media in addition to reducing nanotube toxicity to cells. Unambiguous control and verification of the localization and distribution of SWCNTs within cells, particularly to the nucleus, is needed to advance subcellular technologies utilizing nanotubes. Here we report delivery of SWCNTs to the nucleus by noncovalently attaching the tail domain of the nuclear protein lamin B1 (LB1), which we engineer from the full-length LMNB1 cDNA. More than half of this low molecular weight globular protein is intrinsically disordered but has an immunoglobulin-fold composed of a central hydrophobic core, which is highly suitable for associating with SWCNTs, stably suspending SWCNTs in water and cell media. In addition, LB1 has an exposed nuclear localization sequence to promote active nuclear import of SWCNTs. These SWCNTs-LB1 dispersions in water and cell media display near-infrared (NIR) absorption spectra with sharp van Hove peaks and an NIR fluorescence spectra, suggesting that LB1 individually disperses nanotubes. The dispersing capability of SWCNTs by LB1 is similar to that by albumin proteins. The SWCNTs-LB1 dispersions with concentrations ≥150 μg/mL (≥30 μg/mL) in water (cell media) remain stable for ≥75 days (≥3 days) at 4 °C (37 °C). Further, molecular dynamics modeling of association of LB1 with SWCNTs reveal that the exposure of the nuclear localization sequence is independent of LB1 binding conformation. Measurements from confocal Raman spectroscopy and microscopy, NIR fluorescence imaging of SWCNTs, and fluorescence lifetime imaging microscopy show that millions of these SWCNTs-LB1 complexes enter HeLa cells, localize to the nucleus of cells, and interact with DNA. We postulate that the

  5. 40 CFR 721.10277 - Single-walled and multi-walled carbon nanotubes (generic) (P-10-40).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... not intended to undergo further processing except for mechanical processing. (2) The significant new... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Single-walled and multi-walled carbon... Significant New Uses for Specific Chemical Substances § 721.10277 Single-walled and multi-walled...

  6. An ultrasensitive electrochemical DNA biosensor based on a copper oxide nanowires/single-walled carbon nanotubes nanocomposite

    NASA Astrophysics Data System (ADS)

    Chen, Mei; Hou, Changjun; Huo, Danqun; Yang, Mei; Fa, Huanbao

    2016-02-01

    Here, we developed a novel and sensitive electrochemical biosensor to detect specific-sequence target DNA. The biosensor was based on a hybrid nanocomposite consisting of copper oxide nanowires (CuO NWs) and carboxyl-functionalized single-walled carbon nanotubes (SWCNTs-COOH). The resulting CuO NWs/SWCNTs layers exhibited a good differential pulse voltammetry (DPV) current response for the target DNA sequences, which we attributed to the properties of CuO NWs and SWCNTs. CuO NWs and SWCNTs hybrid composites with highly conductive and biocompatible nanostructure were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and cyclic voltammetry (CV). Immobilization of the probe DNA on the electrode surface was largely improved due to the unique synergetic effect of CuO NWs and SWCNTs. DPV was applied to monitor the DNA hybridization event, using adriamycin as an electrochemical indicator. Under optimal conditions, the peak currents of adriamycin were linear with the logarithm of target DNA concentrations (ranging from 1.0 × 10-14 to 1.0 × 10-8 M), with a detection limit of 3.5 × 10-15 M (signal/noise ratio of 3). The biosensor also showed high selectivity to single-base mismatched target DNA. Compared with other electrochemical DNA biosensors, we showed that the proposed biosensor is simple to implement, with good stability and high sensitivity.

  7. Manifestation of Structure of Electron Bands in Double-Resonant Raman Spectra of Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Stubrov, Yurii; Nikolenko, Andrii; Gubanov, Viktor; Strelchuk, Viktor

    2016-01-01

    Micro-Raman spectra of single-walled carbon nanotubes in the range of two-phonon 2D bands are investigated in detail. The fine structure of two-phonon 2D bands in the low-temperature Raman spectra of the mixture and individual single-walled carbon nanotubes is considered as the reflection of structure of their π-electron zones. The dispersion behavior of 2D band fine structure components in the resonant Raman spectra of single-walled carbon nanotube mixture is studied depending on the energy of excitating photons. The role of incoming and outgoing electron-phonon resonances in the formation of 2D band fine structure in Raman spectra of single-walled carbon nanotubes is analyzed. The similarity of dispersion behavior of 2D phonon bands in single-walled carbon nanotubes, one-layer graphene, and bulk graphite is discussed.

  8. Manifestation of Structure of Electron Bands in Double-Resonant Raman Spectra of Single-Walled Carbon Nanotubes.

    PubMed

    Stubrov, Yurii; Nikolenko, Andrii; Gubanov, Viktor; Strelchuk, Viktor

    2016-12-01

    Micro-Raman spectra of single-walled carbon nanotubes in the range of two-phonon 2D bands are investigated in detail. The fine structure of two-phonon 2D bands in the low-temperature Raman spectra of the mixture and individual single-walled carbon nanotubes is considered as the reflection of structure of their π-electron zones. The dispersion behavior of 2D band fine structure components in the resonant Raman spectra of single-walled carbon nanotube mixture is studied depending on the energy of excitating photons. The role of incoming and outgoing electron-phonon resonances in the formation of 2D band fine structure in Raman spectra of single-walled carbon nanotubes is analyzed. The similarity of dispersion behavior of 2D phonon bands in single-walled carbon nanotubes, one-layer graphene, and bulk graphite is discussed. PMID:26729220

  9. Mass-spectrometric analysis of hydroperoxy- and hydroxy-derivatives of cardiolipin and phosphatidylserine in cells and tissues induced by pro-apoptotic and pro-inflammatory stimuli

    PubMed Central

    Tyurin, Vladimir A.; Tyurina, Yulia Y.; Jung, Mi-Yeon; Tungekar, Muhammad A.; Wasserloos, Karla J.; Bayir, Hülya; Greenberger, Joel S.; Kochanek, Patrick M.; Shvedova, Anna A.; Pitt, Bruce; Kagan, Valerian E.

    2009-01-01

    Oxidation of two anionic phospholipids - cardiolipin (CL) in mitochondria and phosphatidylserine (PS) in extramitochondrial compartments - are important signaling events, particularly during the execution of programmed cell death and clearance of apoptotic cells. Quantitative analysis of CL and PS oxidation products is central to understanding their molecular mechanisms of action. We combined the identification of diverse phospholipid molecular species by ESI-MS with quantitative assessments of lipid hydroperoxides using a fluorescence HPLC-based protocol. We characterized CL and PS oxidation products formed in a model system (cyt c/H2O2), in apoptotic cells (neurons, pulmonary artery endothelial cells) and mouse lung under inflammatory/oxidative stress conditions (hyperoxia, inhalation of single walled carbon nanotubes). Our results demonstrate the usefulness of this approach for quantitative assessments, identification of individual molecular species and structural characterization of anionic phospholipids that are involved in oxidative modification in cells and tissues. PMID:19328050

  10. Single walled carbon nanotube network—Tetrahedral amorphous carbon composite film

    NASA Astrophysics Data System (ADS)

    Iyer, Ajai; Kaskela, Antti; Johansson, Leena-Sisko; Liu, Xuwen; Kauppinen, Esko I.; Koskinen, Jari

    2015-06-01

    Single walled carbon nanotube network (SWCNTN) was coated by tetrahedral amorphous carbon (ta-C) using a pulsed Filtered Cathodic Vacuum Arc system to form a SWCNTN—ta-C composite film. The effects of SWCNTN areal coverage density and ta-C coating thickness on the composite film properties were investigated. X-Ray photoelectron spectroscopy measurements prove the presence of high quality sp3 bonded ta-C coating on the SWCNTN. Raman spectroscopy suggests that the single wall carbon nanotubes (SWCNTs) forming the network survived encapsulation in the ta-C coating. Nano-mechanical testing suggests that the ta-C coated SWCNTN has superior wear performance compared to uncoated SWCNTN.

  11. Thin single-wall BN-nanotubes formed inside carbon nanotubes

    PubMed Central

    Nakanishi, Ryo; Kitaura, Ryo; Warner, Jamie H.; Yamamoto, Yuta; Arai, Shigeo; Miyata, Yasumitsu; Shinohara, Hisanori

    2013-01-01

    We report a high yield synthesis of single-wall boron nitride nanotubes (SWBNNTs) inside single-wall carbon nanotubes (SWCNTs), a nano-templated reaction, using ammonia borane complexes (ABC) as a precursor. Transmission electron microscope (TEM), high angle annular dark field (HAADF)-scanning TEM (STEM), electron energy loss spectra (EELS) and high resolution EELS mapping using aberration-corrected TEM system clearly show the formation of thin SWBNNTs inside SWCNTs. We have found that the yield of the SWBNNT formation is high and that the most of ABC molecules decompose and fuse to form the thin BNNTs at a temperature of 1,673 K having a narrow diameter distribution of 0.7 ± 0.1 nm. Optical absorption measurements suggest that the band gap of the thin SWBNNTs is about 6.0 eV, which provide the ideal insulator nanotubes with very small diameters. PMID:23459405

  12. Synthesis of Single Wall Carbon Nanotubes by Plasma Arc: Role of Plasma Parameters

    NASA Technical Reports Server (NTRS)

    Farhart, Samir; Scott, Carl D.

    2000-01-01

    Single wall carbon nanotubes (SWNT) are porous objects on the molecular scale and have a low density, which gives them potential applications as adsorbent for molecular hydrogen. Their H2 absorption capacity published in the literature varies from 4 to 10% by mass according to the purity of the materials and storage conditions. Optimization of production methods of SWNTs should permit improving these new materials for storage of hydrogen. In this article, we show the potential of using SWNTs in hydrogen storage. In particular, we pose problems associated with synthesis, purification, and opening up of the nanotubes. We present an electric arc process currently used at laboratory scale to produce single wall carbon nanotubes. We discuss, in particular, operating conditions that permit growth of nanotubes and some plasma parameters that assure control of the material. Analysis of the process is carried out with the aid of local measurements of temperature and scanning and transmission electron microscopy of the materials.

  13. Coalescence of parallel finite length single-walled carbon nanotubes by heat treatment

    NASA Astrophysics Data System (ADS)

    Yang, Xueming; Qiao, Fangwei; Zhu, Xiaoxun; Zhang, Pu; Chen, Dongci; To, Albert C.

    2013-03-01

    Fusion of parallel finite length single-walled carbon nanotubes (SWCNTs) without initially introducing structural defects is investigated by molecular dynamics (MD) simulations. Three different models that impose different constraints are adopted to simulate the heat welding and coalescence of the parallel SWCNTs. It is found that the ultrathin as well as some larger diameter, finite length SWCNTs, for example (8,0) and (10,0) SWCNTs can be coalesced to become a unique single-walled tube solely via high temperature heat treatment. It is observed that the ends of the nanotubes are prone to close at high temperature during the high temperature treatment. In addition, the fusion process and mechanism of parallel SWCNTs with different lengths and radii are discussed.

  14. Characterizing energy dissipation in single-walled carbon nanotube polycarbonate composites

    NASA Astrophysics Data System (ADS)

    Koratkar, Nikhil A.; Suhr, Jonghwan; Joshi, Amit; Kane, Ravi S.; Schadler, Linda S.; Ajayan, Pulickel M.; Bartolucci, Steve

    2005-08-01

    In this study, single-walled carbon nanotube and bisphenol-A-polycarbonate composite beams were fabricated by a solution mixing process and dynamic (cyclic) load tests were performed to characterize energy dissipation. We report up to an order of magnitude (>1000%) increase in loss modulus of the polycarbonate system with the addition of 2% weight fraction of oxidized single-walled nanotube fillers. We show that the increase in damping is derived from frictional sliding at the nanotube-polymer interfaces. The nanoscale dimensions of the tubes not only result in large interfacial contact area, thereby generating high damping efficiency, but also enable seamless integration of the filler materials into the composite structure.

  15. Electron backscattering on single-wall carbon nanotubes observed by scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Clauss, W.; Bergeron, D. J.; Freitag, M.; Kane, C. L.; Mele, E. J.; Johnson, A. T.

    1999-09-01

    Single-wall carbon nanotubes, seamless cylindrical molecules formed from a graphene sheet, are either conducting or semiconducting, depending on the particular "wrapping vector" that defines the waist of the tube. Scanning tunneling microscopy experiments have tested this idea by simultaneously measuring a tube's lattice structure and electronic properties. Here we present a series of STM images of single-wall carbon nanotubes with a strikingly rich set of superstructures. The observed patterns can be understood as due to interference between propagating electron waves that are reflected from defects on the tube walls and ends, or as intrinsic to states propagating on semiconducting tubes. The measured broken symmetries can be used to directly probe electronic backscattering on the tube and provide a key element in the understanding of low-energy electron transport on these structures.

  16. Single walled carbon nanotube network—Tetrahedral amorphous carbon composite film

    SciTech Connect

    Iyer, Ajai Liu, Xuwen; Koskinen, Jari; Kaskela, Antti; Kauppinen, Esko I.; Johansson, Leena-Sisko

    2015-06-14

    Single walled carbon nanotube network (SWCNTN) was coated by tetrahedral amorphous carbon (ta-C) using a pulsed Filtered Cathodic Vacuum Arc system to form a SWCNTN—ta-C composite film. The effects of SWCNTN areal coverage density and ta-C coating thickness on the composite film properties were investigated. X-Ray photoelectron spectroscopy measurements prove the presence of high quality sp{sup 3} bonded ta-C coating on the SWCNTN. Raman spectroscopy suggests that the single wall carbon nanotubes (SWCNTs) forming the network survived encapsulation in the ta-C coating. Nano-mechanical testing suggests that the ta-C coated SWCNTN has superior wear performance compared to uncoated SWCNTN.

  17. A black body absorber from vertically aligned single-walled carbon nanotubes

    PubMed Central

    Mizuno, Kohei; Ishii, Juntaro; Kishida, Hideo; Hayamizu, Yuhei; Yasuda, Satoshi; Futaba, Don N.; Yumura, Motoo; Hata, Kenji

    2009-01-01

    Among all known materials, we found that a forest of vertically aligned single-walled carbon nanotubes behaves most similarly to a black body, a theoretical material that absorbs all incident light. A requirement for an object to behave as a black body is to perfectly absorb light of all wavelengths. This important feature has not been observed for real materials because materials intrinsically have specific absorption bands because of their structure and composition. We found a material that can absorb light almost perfectly across a very wide spectral range (0.2–200 μm). We attribute this black body behavior to stem from the sparseness and imperfect alignment of the vertical single-walled carbon nanotubes. PMID:19339498

  18. Regular chemisorption of hydrogen on achiral single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Bogdanova, D. A.; Bulyarskii, S. V.

    2016-07-01

    Regular chemisorption of hydrogen on achiral single-walled carbon nanotubes has been investigated with the use of AM1 quantum-chemical semiempirical method. It has been found that regular hydrogen chemisorption deforms nanotubes, in some cases leading to stable prismatic modifications. The dependence of the adsorption energy on the density of hydrogen coverage has been found. A procedure for determining the adsorption energy by the spectra of thermally stimulated desorption has been proposed.

  19. Structure and Characterization of Vertically Aligned Single-Walled Carbon Nanotube Bundles

    DOE PAGESBeta

    Márquez, Francisco; López, Vicente; Morant, Carmen; Roque-Malherbe, Rolando; Domingo, Concepción; Elizalde, Eduardo; Zamora, Félix

    2010-01-01

    Arrmore » ays of vertically aligned single-walled carbon nanotube bundles, SWCNTs, have been synthesized by simple alcohol catalytic chemical vapor deposition process, carried out at 800°C. The formed SWCNTs are organized in small groups perpendicularly aligned and attached to the substrate. These small bundles show a constant diameter of ca. 30 nm and are formed by the adhesion of no more than twenty individual SWCNTs perfectly aligned along their length.« less

  20. Wrinkling and strain softening in single-wall carbon nanotube membranes.

    PubMed

    Hobbie, E K; Simien, D O; Fagan, J A; Huh, J Y; Chung, J Y; Hudson, S D; Obrzut, J; Douglas, J F; Stafford, C M

    2010-03-26

    The nonlinear elasticity of thin supported membranes assembled from length purified single-wall carbon nanotubes is analyzed through the wrinkling instability that develops under uniaxial compression. In contrast with thin polymer films, pristine nanotube membranes exhibit strong softening under finite strain associated with bond slip and network fracture. We model the response as a shift in percolation threshold generated by strain-induced nanotube alignment in accordance with theoretical predictions. PMID:20366547

  1. Fabrication of Discrete Nanosized Cobalt Particles Encapsulated Inside Single-Walled Carbon Nanotubes

    SciTech Connect

    Zoican Loebick, C.; Majewska, M; Ren, F; Haller, G; Pfefferle, L

    2010-01-01

    Single-walled carbon nanotubes (SWNT) with encapsulated nanosized cobalt particles have been synthesized by a facile and scalable method. In this approach, SWNT were filled with a cobalt acetylacetonate solution in dichloromethane by ultrasonication. In a second step, exposure to hydrogen at different temperatures released discrete cobalt particles of controllable size inside the SWNT cavity. The SWNT-Co particles systems were characterized by transmission electron microscopy, X-ray absorption spectroscopy, Raman spectroscopy, and thermal gravimetric analysis.

  2. Transport properties of a potassium-doped single-wall carbon nanotube rope

    SciTech Connect

    Lee, R. S.; Kim, H. J.; Fischer, J. E.; Lefebvre, J.; Radosavljevic, M.; Hone, J.; Johnson, A. T.

    2000-02-15

    Four-probe resistance vs temperature and gate voltage are reported for an individual single-wall carbon nanotube rope before and after doping in situ with potassium. All the features in R(T) from unoriented bulk material, before and after doping, are qualitatively reproduced by the rope data. The 5.3 K conductance of the pristine rope decreases with positive gate voltage, while G vs V{sub g} becomes featureless after K doping. (c) 2000 The American Physical Society.

  3. Dispersion of Single-Walled Carbon Nanotubes in Poly(E-caprolactone)

    SciTech Connect

    Mitchell,C.; Krishnamoorti, R.

    2007-01-01

    The dispersion of single-walled carbon nanotubes (SWNT) in poly({var_epsilon}-caprolactone) with the aid of a zwitterionic surfactant is reported. Melt rheology and electrical conductivity measurements indicate geometrical percolation and electrical percolation for nanocomposites with {approx}0.08 wt % SWNT, implying an effective anisotropy for the nanotubes of at least 600. Spectroscopic measurements and comparison of dispersion using other surfactants established that the excellent dispersion is a result of the compatibilizing effect of the zwitterionic surfactant.

  4. Tutorial: Linear surface conductivity of an achiral single-wall carbon nanotube

    NASA Astrophysics Data System (ADS)

    Nemilentsau, Andrei M.

    2011-01-01

    Theoretical consideration of electromagnetic scattering by single-wall carbon nanotubes (SWNTs) and SWNT arrays requires knowledge of the linear surface conductivity of an SWNT. An expression for the surface conductivity of an infinitely long SWNT was derived by Slepyan et al. [Phys. Rev. B 60, 17136-17149 (1999)]. The twin purposes of this tutorial are to succinctly discuss the derivation using the density matrix formalism and to provide ready-to-use expressions.

  5. Dispersionless propagation of electron wavepackets in single-walled carbon nanotubes

    SciTech Connect

    Rosati, Roberto; Rossi, Fausto; Dolcini, Fabrizio

    2015-06-15

    We investigate the propagation of electron wavepackets in single-walled carbon nanotubes via a Lindblad-based density-matrix approach that enables us to account for both dissipation and decoherence effects induced by various phonon modes. We show that, while in semiconducting nanotubes the wavepacket experiences the typical dispersion of conventional materials, in metallic nanotubes its shape remains essentially unaltered, even in the presence of the electron-phonon coupling, up to micron distances at room temperature.

  6. Below-gap excitation of semiconducting single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Soavi, G.; Grupp, A.; Budweg, A.; Scotognella, F.; Hefner, T.; Hertel, T.; Lanzani, G.; Leitenstorfer, A.; Cerullo, G.; Brida, D.

    2015-10-01

    We investigate the optoelectronic properties of the semiconducting (6,5) species of single-walled carbon nanotubes by measuring ultrafast transient transmission changes with 20 fs time resolution. We demonstrate that photons with energy below the lowest exciton resonance efficiently lead to linear excitation of electronic states. This finding challenges the established picture of a vanishing optical absorption below the fundamental excitonic resonance. Our result points towards below-gap electronic states as an intrinsic property of semiconducting nanotubes.

  7. The Effects of Single-Wall Carbon Nanotubes on the Shear Piezoelectricity of Biopolymers

    NASA Technical Reports Server (NTRS)

    Lovell, Conrad; Fitz-Gerald, James M.; Harrison, Joycelyn S.; Park, Cheol

    2008-01-01

    Shear piezoelectricity was investigated in a series of composites consisting of increased loadings of single-wall carbon nanotubes (SWCNTs) in poly (gamma-benzyl-L-glutamate), or PBLG. The effects of the SWCNTs on this material property in PBLG will be discussed. Their influence on the morphology of the polymer (degree of orientation and crystallinity), and electrical and dielectric properties of the composite will be reported

  8. Preferential syntheses of semiconducting vertically aligned single-walled carbon nanotubes for direct use in FETs.

    PubMed

    Qu, Liangti; Du, Feng; Dai, Liming

    2008-09-01

    We have combined fast heating with plasma enhanced chemical vapor deposition (PECVD) for preferential growth of semiconducting vertically aligned single-walled carbon nanotubes (VA-SWNTs). Raman spectroscopic estimation indicated a high yield of up to 96% semiconducting SWNTs in the VA-SWNT array. The as-synthesized semiconducting SWNTs can be used directly for fabricating FET devices without the need for any postsynthesis purification or separation. PMID:18665651

  9. Single Wall Carbon Nanotube Alignment Mechanisms for Non-Destructive Evaluation

    NASA Technical Reports Server (NTRS)

    Hong, Seunghun

    2002-01-01

    As proposed in our original proposal, we developed a new innovative method to assemble millions of single wall carbon nanotube (SWCNT)-based circuit components as fast as conventional microfabrication processes. This method is based on surface template assembly strategy. The new method solves one of the major bottlenecks in carbon nanotube based electrical applications and, potentially, may allow us to mass produce a large number of SWCNT-based integrated devices of critical interests to NASA.

  10. Atomic layer deposition on suspended single-walled carbon nanotubes via gas-phase noncovalent functionalization.

    PubMed

    Farmer, Damon B; Gordon, Roy G

    2006-04-01

    Alternating exposures of nitrogen dioxide gas and trimethylaluminum vapor are shown to functionalize the surfaces of single-walled carbon nanotubes with a self-limited monolayer. Functionalized nanotube surfaces are susceptible to atomic layer deposition of continuous, radially isotropic material. This allows for the creation of coaxial nanotube structures of multiple materials with precisely controlled diameters. Functionalization involves only weak physical bonding, avoiding covalent modification, which should preserve the unique optical, electrical, and mechanical properties of the nanotubes. PMID:16608267

  11. Bridged single-walled carbon nanotube-based atomic-scale mass sensors

    NASA Astrophysics Data System (ADS)

    Ali-Akbari, H. R.; Shaat, M.; Abdelkefi, A.

    2016-08-01

    The potentials of carbon nanotubes (CNTs) as mechanical resonators for atomic-scale mass sensing are presented. To this aim, a nonlocal continuum-based model is proposed to study the dynamic behavior of bridged single-walled carbon nanotube-based mass nanosensors. The carbon nanotube (CNT) is considered as an elastic Euler-Bernoulli beam with von Kármán type geometric nonlinearity. Eringen's nonlocal elastic field theory is utilized to model the interatomic long-range interactions within the structure of the CNT. This developed model accounts for the arbitrary position of the deposited atomic-mass. The natural frequencies and associated mode shapes are determined based on an eigenvalue problem analysis. An atom of xenon (Xe) is first considered as a specific case where the results show that the natural frequencies and mode shapes of the CNT are strongly dependent on the location of the deposited Xe and the nonlocal parameter of the CNT. It is also indicated that the first vibrational mode is the most sensitive when the mass is deposited at the middle of a single-walled carbon nanotube. However, when deposited in other locations, it is demonstrated that the second or third vibrational modes may be more sensitive. To investigate the sensitivity of bridged single-walled CNTs as mass sensors, different noble gases are considered, namely Xe, argon (Ar), and helium (He). It is shown that the sensitivity of the single-walled CNT to the Ar and He gases is much lower than the Xe gas due to the significant decrease in their masses. The derived model and performed analysis are so needed for mass sensing applications and particularly when the detected mass is randomly deposited.

  12. Observation of elastic deformations in single-walled carbon nanotubes by Scanning Tunneling Microscopy

    SciTech Connect

    Clauss, Wilfried; Bergeron, David J.; Johnson, Alan T.

    1998-08-11

    Scanning Tunneling Microscopy is used to obtain atomically resolved images of single-walled carbon nanotubes, in ropes of several tens to hundreds of tubes. The images confirm that in this environment strong elastic deformations of the tube lattice occur frequently. In particular, bent and twisted tubes have been identified. The observed distortions could play an important role in explaining the electronic transport properties of nanotubes.

  13. Chirality-dependent boron-mediated growth of nitrogen-doped single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wiltshire, Joseph G.; Li, Lain-Jong; Herz, Laura M.; Nicholas, Robin J.; Glerup, Marianne; Sauvajol, Jean-Louis; Khlobystov, Andrei N.

    2005-11-01

    A change in the relative abundance of single-walled carbon nanotubes, due to the presence of both nitrogen and boron during synthesis, has been identified through Raman and absorption spectroscopy. Raman spectroscopy shows that for two specific branches boron mediates the growth of smaller-diameter zigzag or near-zigzag nanotubes. We combine our experimental results with an improved Kataura model to identify two of the preferentially grown species as (16,0) and (14,1).

  14. Virus sensor based on single-walled carbon nanotube: improved theory incorporating surface effects.

    PubMed

    Elishakoff, Isaac; Challamel, Noël; Soret, Clément; Bekel, Yannis; Gomez, Thomas

    2013-06-28

    In this paper, we deal with the theoretical framework for a single-walled carbon nanotube serving as a virus or bacterium sensor, with the complicating influences of non-locality and surface effects taken into account. It is demonstrated that these effects are not negligible as is often assumed in the literature; they may greatly influence both the vibration behaviour as well as the identification process of the virus or bacterium. PMID:23690635

  15. Intense photoluminescence from dried double-stranded DNA and single-walled carbon nanotube hybrid

    SciTech Connect

    Ito, M.; Kobayashi, T.; Ito, Y.; Hayashida, T.; Nii, D.; Umemura, K.; Homma, Y.

    2014-01-27

    Semiconducting single-walled carbon nanotubes (SWNTs) show near-infrared photoluminescence (PL) when they are individually isolated. This was an obstacle to use photonic properties of SWNTs on a solid surface. We show that SWNTs wrapped with DNA maintain intense PL under the dry conditions. SWNTs are well isolated individually by DNA even when the DNA-SWNT hybrids are agglomerated. This finding opens up application of SWNTs to photonic devices.

  16. Conductivity of Thin Films Based on Single-Walled Carbon Nanotubes Grown by Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Rybakov, M. S.; Kosobutsky, A. V.; Sevostyanov, O. G.; Russakov, D. M.; Lomakin, M. V.; Chirkova, I. M.; Shandakov, S. D.

    2015-03-01

    Electrical and optical properties of thin films of single-walled carbon nanotubes (SWCNT) obtained by aerosol chemical vapor deposition using ethanol, ferrocene, and sulfur are studied. Structural and geometrical characteristics of the synthesis products are determined by the methods of Raman spectroscopy and transmission electron microscopy. The effect of sulfur on the properties of the SWCNTs and thin films based on them is found.

  17. Growth and characterization of high-density mats of single-walled carbon nanotubes for interconnects

    SciTech Connect

    Robertson, J.; Zhong, G.; Telg, H.; Thomsen, C.; Warner, J. H.; Briggs, G. A. D.; Dettlaff-Weglikowska, U.; Roth, S.

    2008-10-20

    We grow high-density, aligned single wall carbon nanotube mats for use as interconnects in integrated circuits by remote plasma chemical vapor deposition from a Fe-Al{sub 2}O{sub 3} thin film catalyst. We carry out extensive Raman characterization of the resulting mats, and find that this catalyst system gives rise to a broad range of nanotube diameters, with no preferential selectivity of semiconducting tubes, but with at least 1/3 of metallic tubes.

  18. A triple quantum dot in a single-wall carbon nanotube.

    PubMed

    Grove-Rasmussen, K; Jørgensen, H I; Hayashi, T; Lindelof, P E; Fujisawa, T

    2008-04-01

    A top-gated single-wall carbon nanotube is used to define three coupled quantum dots in series between two electrodes. The additional electron number on each quantum dot is controlled by top-gate voltages allowing for current measurements of single, double, and triple quantum dot stability diagrams. Simulations using a capacitor model including tunnel coupling between neighboring dots captures the observed behavior with good agreement. Furthermore, anticrossings between indirectly coupled levels and higher order cotunneling are discussed. PMID:18314966

  19. Method for separating single-wall carbon nanotubes and compositions thereof

    NASA Technical Reports Server (NTRS)

    Smalley, Richard E. (Inventor); Hauge, Robert H. (Inventor); Kittrell, W. Carter (Inventor); Sivarajan, Ramesh (Inventor); Strano, Michael S. (Inventor); Bachilo, Sergei M. (Inventor); Weisman, R. Bruce (Inventor)

    2006-01-01

    The invention relates to a process for sorting and separating a mixture of (n, m) type single-wall carbon nanotubes according to (n, m) type. A mixture of (n, m) type single-wall carbon nanotubes is suspended such that the single-wall carbon nanotubes are individually dispersed. The nanotube suspension can be done in a surfactant-water solution and the surfactant surrounding the nanotubes keeps the nanotube isolated and from aggregating with other nanotubes. The nanotube suspension is acidified to protonate a fraction of the nanotubes. An electric field is applied and the protonated nanotubes migrate in the electric fields at different rates dependent on their (n, m) type. Fractions of nanotubes are collected at different fractionation times. The process of protonation, applying an electric field, and fractionation is repeated at increasingly higher pH to separated the (n, m) nanotube mixture into individual (n, m) nanotube fractions. The separation enables new electronic devices requiring selected (n, m) nanotube types.

  20. High-power supercapacitor electrodes from single-walled carbon nanohorn/nanotube composite.

    PubMed

    Izadi-Najafabadi, Ali; Yamada, Takeo; Futaba, Don N; Yudasaka, Masako; Takagi, Hideyuki; Hatori, Hiroaki; Iijima, Sumio; Hata, Kenji

    2011-02-22

    A novel composite is presented as a supercapacitor electrode with a high maximum power rating (990 kW/kg; 396 kW/l) exceeding power performances of other electrodes. The high-power capability of the electrode stemmed from its unique meso-macro pore structure engineered through the utilization of single-walled carbon nanotubes (20 wt %) as scaffolding for single-walled carbon nanohorns (80 wt %). The novel composite electrode also exhibited durable operation (6.5% decline in capacitance over 100 000 cycles) as a result of its monolithic chemical composition and mechanical stability. The novel composite electrode was benchmarked against another high-power electrode made from single-walled carbon nanotubes (Bucky paper electrode). While the composite electrode had a lower surface area compared to the Bucky paper electrode (280 vs 470 m(2)/g from nitrogen adsorption), it had a higher meso-macro pore volume (2.6 vs 1.6 mL/g from mercury porosimetry) which enabled the composite electrode to retain more electrolyte, ensuring facile ion transport, hence achieving a higher maximum power rating (970 vs 400 kW/kg). PMID:21210712

  1. Single-Walled Carbon Nanotubes as Fluorescence Biosensors for Pathogen Recognition in Water Systems

    DOE PAGESBeta

    Upadhyayula, Venkata K. K.; Ghoshroy, Soumitra; Nair, Vinod S.; Smith, Geoffrey B.; Mitchell, Martha C.; Deng, Shuguang

    2008-01-01

    Tmore » he possibility of using single-walled carbon nanotubes (SWCNTs) aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations of Staphylococcus aureus aureus SH 1000 and Escherichia coli pKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies.he Freundlich adsorption equilibrium constant ( k ) for S.aureus and E.coli determined from batch adsorption study was found to be 9 × 10 8 and 2 × 10 8  ml/g, respectively.he visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen.he results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability.his is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.« less

  2. Controlled Patterning and Growth of Single Wall and Multi-wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Delzeit, Lance D. (Inventor)

    2005-01-01

    Method and system for producing a selected pattern or array of at least one of a single wall nanotube and/or a multi-wall nanotube containing primarily carbon. A substrate is coated with a first layer (optional) of a first selected metal (e.g., Al and/or Ir) and with a second layer of a catalyst (e.g., Fe, Co, Ni and/or Mo), having selected first and second layer thicknesses provided by ion sputtering, arc discharge, laser ablation, evaporation or CVD. The first layer and/or the second layer may be formed in a desired non-uniform pattern, using a mask with suitable aperture(s), to promote growth of carbon nanotubes in a corresponding pattern. A selected heated feed gas (primarily CH4 or C2Hn with n=2 and/or 4) is passed over the coated substrate and forms primarily single wall nanotubes or multiple wall nanotubes, depending upon the selected feed gas and its temperature. Nanofibers, as well as single wall and multi-wall nanotubes, are produced using plasma-aided growth from the second (catalyst) layer. An overcoating of a selected metal or alloy can be deposited, over the second layer, to provide a coating for the carbon nanotubes grown in this manner.

  3. Characterization of Plasmodium phosphatidylserine decarboxylase expressed in yeast and application for inhibitor screening

    PubMed Central

    Choi, Jae-Yeon; Lawres, Lauren; Toh, Justin Y.; Voelker, Dennis R.; Ben Mamoun, Choukri

    2016-01-01

    Summary Phospholipid biosynthesis is critical for the development, differentiation and pathogenesis of several eukaryotic pathogens. Genetic studies have validated the pathway for phosphatidylethanolamine synthesis from phosphatidylserine catalyzed by phosphatidylserine decarboxylase enzymes (PSD) as a suitable target for development of antimicrobials; however no inhibitors of this class of enzymes have been discovered. We show that the Plasmodium falciparum PSD can restore the essential function of the yeast gene in strains requiring PSD for growth. Genetic, biochemical and metabolic analyses demonstrate that amino acids between positions 40 and 70 of the parasite enzyme are critical for proenzyme processing and decarboxylase activity. We used the essential role of Plasmodium PSD in yeast as a tool for screening a library of anti-malarials. One of these compounds is 7-chloro-N-(4-ethoxyphenyl)-4-quinolinamine, an inhibitor with potent activity against P. falciparum, and low toxicity toward mammalian cells. We synthesized an analog of this compound and showed that it inhibits PfPSD activity and eliminates Plasmodium yoelii infection in mice. These results highlight the importance of 4-quinolinamines as a novel class of drugs targeting membrane biogenesis via inhibition of PSD activity PMID:26585333

  4. Synergistic enhancement of cancer therapy using a combination of docetaxel and photothermal ablation induced by single-walled carbon nanotubes

    PubMed Central

    Wang, Lei; Zhang, Mingyue; Zhang, Nan; Shi, Jinjin; Zhang, Hongling; Li, Min; Lu, Chao; Zhang, Zhenzhong

    2011-01-01

    Background Single-walled carbon nanotubes (SWNT) are poorly soluble in water, so their applications are limited. Therefore, aqueous solutions of SWNT, designed by noncovalent functionalization and without toxicity, are required for biomedical applications. Methods In this study, we conjugated docetaxel with SWNT via π-π accumulation and used a surfactant to functionalize SWNT noncovalently. The SWNT were then conjugated with docetaxel (DTX-SWNT) and linked with NGR (Asn-Gly-Arg) peptide, which targets tumor angiogenesis, to obtain a water-soluble and tumor-targeting SWNT-NGR-DTX drug delivery system. Results SWNT-NGR-DTX showed higher efficacy than docetaxel in suppressing tumor growth in a cultured PC3 cell line in vitro and in a murine S180 cancer model. Tumor volumes in the S180 mouse model decreased considerably under near-infrared radiation compared with the control group. Conclusion The SWNT-NGR-DTX drug delivery system may be promising for high treatment efficacy with minimal side effects in future cancer therapy. PMID:22114495

  5. Highly Specific and Cost-Efficient Detection of Salmonella Paratyphi A Combining Aptamers with Single-Walled Carbon Nanotubes

    PubMed Central

    Yang, Ming; Peng, Zhihui; Ning, Yi; Chen, Yongzhe; Zhou, Qin; Deng, Le

    2013-01-01

    In this paper, a panel of single-stranded DNA aptamers with high affinity and specificity against Salmonella Paratyphi A was selected from an enriched oligonucleotide pool by a whole-cell-Systematic Evolution of Ligands by Exponential Enrichment (SELEX) procedure, during which four other Salmonella serovars were used as counter-selection targets. It was determined through a fluorescence assay that the selected aptamers had high binding ability and specificity to this pathogen. The dissociation constant of these aptamers were up to nanomolar range, and aptamer Apt22 with the lowest Kd (47 ± 3 nM) was used in cell imaging experiments. To detect this bacteria with high specificity and cost-efficiently, a novel useful detection method was also constructed based on the noncovalent self-assembly of single-walled carbon nanotubes (SWNTs) and DNAzyme-labeled aptamer detection probes. The amounts of target bacteria could be quantified by exploiting chemoluminescence intensity changes at 420 nm and the detection limit of the method was 103 cfu/mL. This study demonstrated the applicability of Salmonella specific aptamers and their potential for use in the detection of Salmonella in food, clinical and environmental samples. PMID:23698275

  6. Organic/hybrid nanoparticles and single-walled carbon nanotubes: preparation methods and chiral applications.

    PubMed

    Alhassen, Haysem; Antony, Vijy; Ghanem, Ashraf; Yajadda, Mir Massoud Aghili; Han, Zhao Jun; Ostrikov, Kostya Ken

    2014-11-01

    Nanoparticles are molecular-sized solids with at least one dimension measuring between 1-100 nm or 10-1000 nm depending on the individual discipline's perspective. They are aggregates of anywhere from a few hundreds to tens of thousands of atoms which render them larger than molecules but smaller than bulk solids. Consequently, they frequently exhibit physical and chemical properties somewhere between. On the other hand, nanocrystals are a special class of nanoparticles which have started gaining attention recently owing to their unique crystalline structures which provide a larger surface area and promising applications including chiral separations. Hybrid nanoparticles are supported by the growing interest of chemists, physicists, and biologists, who are researching to fully exploit them. These materials can be defined as molecular or nano-composites with mixed (organic or bio) and inorganic components, where at least one of the component domain has a dimension ranging from a few Å to several nanometers. Similarly, and due to their extraordinary physical, chemical, and electrical properties, single-walled carbon nanotubes have been the subject of intense research. In this short review, the focus is mainly on the current well-established simple preparation techniques of chiral organic and hybrid nanoparticles as well as single-walled carbon nanotubes and their applications in separation science. Of particular interest, cinchonidine, chitosan, and β-CD-modified gold nanoparticles (GNPs) are discussed as model examples for organic and hybrid nanoparticles. Likewise, the chemical vapor deposition method, used in the preparation of single-walled carbon nanotubes, is discussed. The enantioseparation applications of these model nanomaterials is also presented. PMID:24811353

  7. Single-walled carbon nanotubes acquire a specific lectin-affinity through supramolecular wrapping with lactose-appended schizophyllan.

    PubMed

    Hasegawa, Teruaki; Fujisawa, Tomohisa; Numata, Munenori; Umeda, Mariko; Matsumoto, Takahiro; Kimura, Taro; Okumura, Shiro; Sakurai, Kazuo; Shinkai, Seiji

    2004-10-01

    Single-walled carbon nanotubes can be entrapped within a helical superstructure composed of schizophyllan bearing lactoside-appendages to show an excellent water-solubility as well as a specific lectin-affinity. PMID:15467846

  8. Stabilities and mechanical and electronic properties on BN doped zigzag single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Vongachariya, Arthit; Parasuk, Vudhichai

    2015-12-01

    Electronic structures of undoped and BN doped zigzag (8,0) single-walled carbon nanotube (SWCNT) were investigated using density functional theoretical calculations. Their stabilities due to BN doping and spin states were considered and those with the shortest B-N distance and singlet spin is the most stable. The BN substitution also causes the reduction of the band gap energy. While the BN doping reduces the band gap energy from 0.606 to 0.183 eV, it has no effect on the Young's modulus value. The band gap energy of SWCNTs can be varied upon applying stress. At high stress ratio, SWCNT could become metallic.

  9. Temperature Dependence of the Thermal Conductivity of Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Osman, Mohamed A.; Srivastava, Deepak

    2000-01-01

    The thermal conductivity of several single wall carbon nanotubes (CNT) has been calculated over a temperature range of 100-500 K using molecular dynamics simulations with Tersoff-Brenner potential for C-C interactions. In all cases, starting from similar values at 100K, thermal conductivities show a peaking behavior before falling off at higher temperatures. The peak position shifts to higher temperatures for nanotubes of larger diameter, and no significant dependence on the tube chirality is observed. It is shown that this phenomenon is due to onset of Umklapp scattering, which shifts to higher temperatures for nanotubes of larger diameter.

  10. Carbohydrate Conjugation through Microwave-Assisted Functionalization of Single-Walled Carbon Nanotubes Using Perfluorophenyl Azides

    PubMed Central

    Kong, Na; Shimpi, Manishkumar R.; Park, Jae Hyeung

    2015-01-01

    Carbohydrate-functionalized single-walled carbon nanotubes (SWNTs) were synthesized using microwave-assisted reaction of perfluorophenyl azide with the nanotubes. The results showed that microwave radiation provides a rapid and effective means to covalently attach carbohydrates to SWNTs, producing carbohydrate-SWNT conjugates for biorecognition. The carbohydrate-functionalized SWNTs were furthermore shown to interact specifically with cognate carbohydrate-specific proteins (lectins), resulting in predicted recognition patterns. The carbohydrate-presenting SWNTs constitute a new platform for sensitive protein- or cell recognition, which pave the way for glycoconjugated carbon nanomaterials in biorecognition applications. PMID:25746392

  11. Influence of cysteine doping on photoluminescence intensity from semiconducting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kurnosov, N. V.; Leontiev, V. S.; Linnik, A. S.; Karachevtsev, V. A.

    2015-03-01

    Photoluminescence (PL) from semiconducting single-walled carbon nanotubes can be applied for detection of cysteine. It is shown that cysteine doping (from 10-8 to 10-3 M) into aqueous suspension of nanotubes with adsorbed DNA leads to increase of PL intensity. The PL intensity was enhanced by 27% at 10-3 M cysteine concentration in suspension. Most likely, the PL intensity increases due to the passivation of p-defects on the nanotube by the cysteine containing reactive thiol group. The effect of doping with other amino acids without this group (methionine, serine, aspartic acid, lysine, proline) on the PL intensity is essentially weaker.

  12. Characterizations of Enriched Metallic Single-Walled Carbon Nanotubes in Polymer Composite

    NASA Technical Reports Server (NTRS)

    Chen, Bin; Li, Jing; Lu, Yijiang; Cinke, Martin; Au, Dyng; Harmon, Julie P.; Muisener, Patricia Anne O.; Clayton, LaNetra; D'Angelo, John

    2003-01-01

    Using different processing conditions, we disperse the single-walled carbon nanotube (SWNT) into the polymethyl methacrylate (PMMA) to form composites. In the melt-blended sample, the SWNTs originally semiconducting - became predominantly metallic after dispersion into the melt-blended composite. The interaction of the PMMA and SWNT is investigated by the polarized Raman studies. The structure changes in the PMMA and SWNT shows that the anisotropic interactions are responsible for SWNT electronic density of states (DOS) changes. The increased metallic SWNT percentage is confirmed by the conductivity and dielectric constant measurements .

  13. Fatigue failure mechanisms of single-walled carbon nanotube ropes embedded in epoxy

    NASA Astrophysics Data System (ADS)

    Ren, Y.; Fu, Y. Q.; Liao, K.; Li, F.; Cheng, H. M.

    2004-04-01

    In this work, fatigue failure mechanisms of single-walled carbon nanotube (SWCNT) bundles embedded in epoxy matrix under repeated tensile load were studied. Observed damage and failure modes include: (1) splitting of SWCNT bundles, (2) kink formation and subsequent failure in SWCNTs, and (3) fracture of SWCNT bundles. Patterns of crack propagation under tension in SWCNTs were studied by molecular mechanics simulations, where defect-free SWCNTs and SWCNTs with two different modes of Stone-Wales defects were studied. It is demonstrated by the results of molecular mechanics simulation that the observed fracture surfaces of SWCNT can be reproduced reasonably well, suggesting possible fatigue failure mechanisms of SWCNT in the composite.

  14. Reinforcement of semicrystalline polymers with collagen-modified single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Sanjib; Salvetat, Jean-Paul; Saboungi, Marie-Louise

    2006-06-01

    We report on the enhancement of the mechanical properties of single wall carbon nanotube (SWNT)-polyvinyl alcohol (PVA) composites through functionalization of SWNTs with denatured collagen. In addition to improving compatibility with the matrix, the denatured collagen layer was found to increase the PVA matrix crystallinity, which results in a dramatic enhancement of the Young's modulus (260%), tensile strength (300%), and toughness (700%) well above what can be expected with the classical rule of mixture. A supramolecular organization at the interface is associated with an increase of PVA crystallinity as shown by the x-ray diffraction and differential scanning calorimetry.

  15. Polarized resonance Raman spectroscopy of single-wall carbon nanotubes within a polymer under strain

    NASA Astrophysics Data System (ADS)

    Frogley, M. D.; Zhao, Q.; Wagner, H. D.

    2002-03-01

    The D* Raman band of single-wall carbon nanotubes aligned by shear flow in a polymer matrix has been measured as a function of tensile strain. The Raman intensity varies with the optical polarization direction, an effect which is used here to assess the degree of tube alignment. The strain dependence of the Raman shift depends strongly on the nanotube orientation and the polarization direction. We show that, using polarized light, unoriented nanotubes can be used as strain sensors so that no tube alignment is necessary and the strain can be measured in all directions in a single sample.

  16. [Surface modification and microstructure of single-walled carbon nanotubes for dental composite resin].

    PubMed

    Xia, Yang; Zhang, Feimin; Xu, Li'na; Gu, Ning

    2006-12-01

    In order to improve its dispersion condition in dental composite resin and enhance its interaction with the matrix, single-walled carbon nanotubes(SWNTs) were refluxed and oxidized, then treated by APTE. Their outer surface were coated by nano-SiO2 particles using sol-gel process, then further treated by organosilanes ATES. IR and TEM were used to analyze modification results. TEM pictures showed nano-particles were on the surface of SWNTs; IR showed characteristic adsorbing bands of SiO2. Composite resin specimen with modified SWNTs was prepared and examined by TEM. SWNTs were detected in composite resin matrix among other inorganic fillers. PMID:17228726

  17. Red-emitting π-conjugated oligomers infused single-wall carbon nanotube sheets

    NASA Astrophysics Data System (ADS)

    Fujimori, Toshihiko; Urita, Koki

    2016-04-01

    We demonstrate the one-step thermal fusion and infusion of pyrene molecules inside single-wall carbon nanotubes (SWCNTs). Despite the presence of metallic-SWCNTs, which behave as a quencher due to gapless electronic states, the nanohybrids consisting of pyrene and/or azupyrene oligomers infused SWCNT sheets exhibit red fluorescence by the ultraviolet, blue, and green light excitations. The wavelength-independent light-emitting behavior is explained by (1) infused PAH oligomers inside semiconducting-SWCNTs and (2) the peculiar π-π interaction through mixed π-conjugated state between the π-conjugated oligomers and non-armchair metallic-SWCNTs.

  18. Quantification of thin graphene sheets contained in spherical aggregates of single-walled carbon nanohorns

    NASA Astrophysics Data System (ADS)

    Irie, Michiko; Nakamura, Maki; Zhang, Minfang; Yuge, Ryota; Iijima, Sumio; Yudasaka, Masako

    2010-11-01

    Spherical aggregates of single-walled carbon nanohorns (SWNHs) produced by CO 2 laser ablation of graphite contain thin graphene sheets (TGSs), and their quantities depend on formation conditions. To adjust laser ablation condition to increase TGS quantities, TGS quantification in products is necessary; however, its method has not been established. We have found that high resolution thermogravimetric analysis (HRTGA) showed SWNHs and TGSs combusting at 554 and 581 °C, respectively. Transmission electron microscopy observations of HRTGA-residues obtained by stopping HRTGA on the way supported these assignments. Thus TGS was able to be quantified by analyzing derivative curves of weight vs. temperature curves.

  19. Creep-resistant composites of alumina and single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zapata-Solvas, Eugenio; Poyato, Rosalía; Gómez-García, Diego; Domínguez-Rodríguez, Arturo; Radmilovic, Velimir; Padture, Nitin P.

    2008-03-01

    Composites of alumina (Al2O3) ceramic and single-wall carbon nanotubes (SWNTs) have been tested in uniaxial compression at 1300 and 1350°C (Ar atmosphere), and they have been found to be about two orders of magnitude more creep-resistant compared to a pure alumina of about the same grain size (0.5μm). This is attributed to partial blocking of grain-boundary sliding by SWNTs in the composites. Since the grain boundaries in the ceramic/SWNTs composites are amenable to being engineered, this constitutes an attractive approach to the design of creep-resistant ceramic composites.

  20. Effects of ion beam heating on Raman spectra of single-walled carbon nanotubes

    SciTech Connect

    Hulman, Martin; Skakalova, Viera; Krasheninnikov, A. V.; Roth, S.

    2009-02-16

    Free standing films of single-wall carbon nanotubes were irradiated with energetic N{sup +} and C{sup 4+} ions. The observed changes in the Raman line shape of the radial breathing mode and the G band of the C{sup 4+} irradiated samples were similar to those found for a thermally annealed sample. We ascribe these changes to thermal desorption of volatile dopants from the initially doped nanotubes. A simple geometry of the experiment allows us to estimate the temperature rise by one-dimensional heat conductance equation. The calculation indicates that irradiation-mediated increase in temperature may account for the observed Raman spectra changes.

  1. Hydrogenation of single-wall carbon nanotubes using polyamine reagents: combined experimental and theoretical study.

    PubMed

    Miller, Glen P; Kintigh, Jeremy; Kim, Eunja; Weck, Philippe F; Berber, Savas; Tomanek, David

    2008-02-20

    We combine experimental observations with ab initio calculations to study the reversible hydrogenation of single-wall carbon nanotubes using high boiling polyamines as hydrogenation reagents. Our calculations characterize the nature of the adsorption bond and identify preferential adsorption geometries at different coverages. We find the barrier for sigmatropic rearrangement of chemisorbed hydrogen atoms to be approximately 1 eV, thus facilitating surface diffusion and formation of energetically favored, axially aligned adsorbate chains. Chemisorbed hydrogen modifies the structure and stability of nanotubes significantly and increases the inter-tube distance, thus explaining the improved dispersability in solvents like methanol, ethanol, chloroform, and benzene. PMID:18220395

  2. Universal empirical formula for optical transition energies of semiconducting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Jamal, G. R. Ahmed; Mominuzzaman, S. M.

    2016-01-01

    A general empirical relation for calculating first seven optical transition energies of semiconducting single wall carbon nanotubes (SWCNTs) is proposed here for the first time. The proposed formula effectively relates first seven optical transition energies of semiconducting SWCNTs with their chiral indices (n, m) through exponential form containing two specific terms (n+2m) and (2n-m). Both mod 1 and mod 2 types of semiconducting tubes are considered here over a wide diameter range from 0.4 nm to 4.75 nm. It was observed that the proposed empirical relations can predict the recent experimental data of those optical transitions with high accuracy.

  3. Doping of single-walled carbon nanotubes controlled via chemical transformation of encapsulated nickelocene.

    PubMed

    Kharlamova, Marianna V; Sauer, Markus; Saito, Takeshi; Sato, Yuta; Suenaga, Kazu; Pichler, Thomas; Shiozawa, Hidetsugu

    2015-01-28

    Controlled doping of carbon nanotubes is elemental for their electronic applications. Here we report an approach to tune the polarity and degree of doping of single-walled carbon nanotubes via filling with nickelocene followed by encapsulated reactions. Using Raman, photoemission spectroscopy and transmission electron microscopy, we show that nickelocene molecules transform into nickel carbides, nickel and inner carbon nanotubes with reaction temperatures as low as 250 °C. The doping efficiency is determined for each chemical component. Synchronous charge transfer among the molecular components allows bipolar doping of the carbon nanotubes to be achieved in a broad range of ±0.0012 e(-) per carbon. PMID:25503929

  4. All-optical trion generation in single-walled carbon nanotubes.

    PubMed

    Santos, Silvia M; Yuma, Bertrand; Berciaud, Stéphane; Shaver, Jonah; Gallart, Mathieu; Gilliot, Pierre; Cognet, Laurent; Lounis, Brahim

    2011-10-28

    We present evidence of all-optical trion generation and emission in pristine single-walled carbon nanotubes (SWCNTs). Luminescence spectra, recorded on individual SWCNTs over a large cw excitation intensity range, show trion emission peaks redshifted with respect to the bright exciton peak. Clear chirality dependence is observed for 22 separate SWCNT species, allowing for determination of electron-hole exchange interaction and trion binding energy contributions. Luminescence data together with ultrafast pump-probe experiments on chirality-sorted bulk samples suggest that exciton-exciton annihilation processes generate dissociated carriers that allow for trion creation upon a subsequent photon absorption event. PMID:22107671

  5. Nonlinear photoluminescence properties of trions in hole-doped single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Akizuki, Naoto; Iwamura, Munechiyo; Mouri, Shinichiro; Miyauchi, Yuhei; Kawasaki, Tomohiro; Watanabe, Hiroshi; Suemoto, Tohru; Watanabe, Kouta; Asano, Kenichi; Matsuda, Kazunari

    2014-05-01

    We studied the excitation density dependence of photoluminescence (PL) spectra of excitons and trions (charged excitons) in hole-doped single-walled carbon nanotubes. We found that the PL intensity of trions exhibited a strong nonlinear saturation behavior as the excitation density increased, whereas that of excitons exhibited a weak sublinear behavior. The strong PL saturation of trions is attributed to depletion of doped holes that are captured by excitons in the formation processes. Moreover, the effective radiative lifetime of a trion was evaluated to be approximately 20 ns.

  6. Electronic Durability of Flexible Transparent Films from Type-Specific Single-Wall Carbon Nanotubes

    SciTech Connect

    Harris, J; Iyer, S; Bernhardt, A; Huh, JY; Hudson, S; Fagan, J; Hobbie, E.

    2011-12-11

    The coupling between mechanical flexibility and electronic performance is evaluated for thin films of metallic and semiconducting single-wall carbon nanotubes (SWCNTs) deposited on compliant supports. Percolated networks of type-purified SWCNTs are assembled as thin conducting coatings on elastic polymer substrates, and the sheet resistance is measured as a function of compression and cyclic strain through impedance spectroscopy. The wrinkling topography, microstructure and transparency of the films are independently characterized using optical microscopy, electron microscopy, and optical absorption spectroscopy. Thin films made from metallic SWCNTs show better durability as flexible transparent conductive coatings, which we attribute to a combination of superior mechanical performance and higher interfacial conductivity.

  7. New Method Developed To Purify Single Wall Carbon Nanotubes for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Lebron, Marisabel; Meador, Michael A.

    2003-01-01

    Single wall carbon nanotubes have attracted considerable attention because of their remarkable mechanical properties and electrical and thermal conductivities. Use of these materials as primary or secondary reinforcements in polymers or ceramics could lead to new materials with significantly enhanced mechanical strength and electrical and thermal conductivity. Use of carbon-nanotube-reinforced materials in aerospace components will enable substantial reductions in component weight and improvements in durability and safety. Potential applications for single wall carbon nanotubes include lightweight components for vehicle structures and propulsion systems, fuel cell components (bipolar plates and electrodes) and battery electrodes, and ultra-lightweight materials for use in solar sails. A major barrier to the successful use of carbon nanotubes in these components is the need for methods to economically produce pure carbon nanotubes in large enough quantities to not only evaluate their suitability for certain applications but also produce actual components. Most carbon nanotube synthesis methods, including the HiPCO (high pressure carbon monoxide) method developed by Smalley and others, employ metal catalysts that remain trapped in the final product. These catalyst impurities can affect nanotube properties and accelerate their decomposition. The development of techniques to remove most, if not all, of these impurities is essential to their successful use in practical applications. A new method has been developed at the NASA Glenn Research Center to purify gram-scale quantities of single wall carbon nanotubes. This method, a modification of a gas phase purification technique previously reported by Smalley and others, uses a combination of high-temperature oxidations and repeated extractions with nitric and hydrochloric acid. This improved procedure significantly reduces the amount of impurities (catalyst and nonnanotube forms of carbon) within the nanotubes, increasing

  8. On the charge transfer between single-walled carbon nanotubes and graphene

    SciTech Connect

    Rao, Rahul Pierce, Neal; Dasgupta, Archi

    2014-08-18

    It is important to understand the electronic interaction between single-walled carbon nanotubes (SWNTs) and graphene in order to use them efficiently in multifunctional hybrid devices. Here, we deposited SWNT bundles on graphene-covered copper and SiO{sub 2} substrates by chemical vapor deposition and investigated the charge transfer between them by Raman spectroscopy. Our results revealed that, on both copper and SiO{sub 2} substrates, graphene donates electrons to the SWNTs, resulting in p-type doped graphene and n-type doped SWNTs.

  9. Single wall carbon nanohorn as a drug carrier for controlled release

    NASA Astrophysics Data System (ADS)

    Xu, Jianxun; Yudasaka, Masako; Kouraba, Sachio; Sekido, Mitsuru; Yamamoto, Yuhei; Iijima, Sumio

    2008-08-01

    A single wall carbon nanohorn (SWNH) is a new kind of single-graphene tubules with a diameter of 2-5 nm and a length 40-50 nm. In this work, we used oxidized SWNH (SWNHox) to incorporate vancomycin hydrochloride (VCM) for its controlled release by taking advantage of the interactions between VCM and SWNHox. Phospholipid-poly(ethylene glycol) was used to modify the hydrophobic surface of SWNHox to improve its dispersion in aqueous systems. In the release study using this complex, a stable release of VCM was achieved for an extended period.

  10. Purification of single-wall carbon nanotubes by using ultrafine gold particles

    NASA Astrophysics Data System (ADS)

    Nihey, Fumiyuki; Mizoguti, Eiji; Yudasaka, Masako; Iijima, Sumio; Ichihashi, Toshinari; Nakamura, Kazuo

    2000-03-01

    The purification of single-wall carbon nanotubes (SWNTs) is needed to enable detailed characterization and some application of this material. We report a purification method utilizing ultrafine gold particles as catalysts to selectively oxidize carbonaceous impurities in SWNT soot. The ultrafine gold particles with a diameter of 20 nm were dispersed in the soot in combination with benzalkonium chloride as surfactant. Thermogravimetric analyses and electron microscopy observations revealed that oxidation occured at about 330^circC for carbonaceous impurities and at about 410^circC for SWNTs. This selective oxidation enabled us to purify SWNTs and make the quantitative analyses of SWNTs.

  11. Electronic modulations in a single wall carbon nanotube induced by the Au(111) surface reconstruction

    SciTech Connect

    Clair, Sylvain; Shin, Hyung-Joon; Kim, Yousoo E-mail: maki@riken.jp; Kawai, Maki E-mail: maki@riken.jp

    2015-02-02

    The structural and electronic structure of single wall carbon nanotubes adsorbed on Au(111) has been investigated by low-temperature scanning tunneling microscopy and spectroscopy. The nanotubes were dry deposited in situ in ultrahigh vacuum onto a perfectly clean substrate. In some cases, the native herringbone reconstruction of the Au(111) surface interacted directly with adsorbed nanotubes and produced long-range periodic oscillations in their local density of states, corresponding to charge transfer modulations along the tube axis. This effect, however, was observed not systematically for all tubes and only for semiconducting tubes.

  12. Growth of semiconducting single-walled carbon nanotubes by using ceria as catalyst supports.

    PubMed

    Qin, Xiaojun; Peng, Fei; Yang, Feng; He, Xiaohui; Huang, Huixin; Luo, Da; Yang, Juan; Wang, Sheng; Liu, Haichao; Peng, Lianmao; Li, Yan

    2014-02-12

    The growth of semiconducting single-walled carbon nanotubes (s-SWNTs) on flat substrates is essential for the application of SWNTs in electronic and optoelectronic devices. We developed a flexible strategy to selectively grow s-SWNTs on silicon substrates using a ceria-supported iron or cobalt catalysts. Ceria, which stores active oxygen, plays a crucial role in the selective growth process by inhibiting the formation of metallic SWNTs via oxidation. The so-produced ultralong s-SWNT arrays are immediately ready for building field effect transistors. PMID:24392872

  13. Molecular adsorption study of nicotine and caffeine on single-walled carbon nanotubes from first principles

    NASA Astrophysics Data System (ADS)

    Lee, Hyung-June; Kim, Gunn; Kwon, Young-Kyun

    2013-08-01

    Using first-principles calculations, we investigate the electronic structures and binding properties of nicotine and caffeine adsorbed on single-walled carbon nanotubes to determine whether CNTs are appropriate for filtering or sensing nicotine and caffeine molecules. We find that caffeine adsorbs more strongly than nicotine. The different binding characteristics are discussed by analyzing the modification of the electronic structure of the molecule-adsorbed CNTs. We also calculate the quantum conductance of the CNTs in the presence of nicotine or caffeine adsorbates and demonstrate that the influence of caffeine is stronger than nicotine on the conductance of the host CNT.

  14. Determination of the acidic sites of purified single-walled carbon nanotubes by acid base titration

    NASA Astrophysics Data System (ADS)

    Hu, H.; Bhowmik, P.; Zhao, B.; Hamon, M. A.; Itkis, M. E.; Haddon, R. C.

    2001-09-01

    We report the measurement of the acidic sites in three different samples of commercially available full-length purified single-walled carbon nanotubes (SWNTs) - as obtained from CarboLex (CLI), Carbon Solutions (CSI) and Tubes@Rice (TAR) - by simple acid-base titration methods. Titration of the purified SWNTs with NaOH and NaHCO 3 solutions was used to determine the total percentage of acidic sites and carboxylic acid groups, respectively. The total percentage of acidic sites in full length purified SWNTs from TAR, CLI and CSI are about 1-3%.

  15. In Vivo Delivery of Nitric Oxide-Sensing, Single-Walled Carbon Nanotubes

    PubMed Central

    Iverson, Nicole M; Strano, Michael S; Wogan, Gerald N

    2015-01-01

    Detection of nitric oxide (NO) in vivo by single walled carbon nanotubes (SWNT) is based on the fluorescent properties of SWNT and the ability of NO to quench the fluorescence signal. Alterations of the signal can be utilized to detect a small molecule in vivo that has not previously been possible by other assay techniques. The protocols described here explain the techniques used to prepare NO-detecting SWNTs and to administer them to mice by both intravenous and subcutaneous routes. These techniques can also be utilized with other SWNT sensors as well as non-SWNT sensors. PMID:26344235

  16. A comparative study of argon ion irradiated pristine and fluorinated single-wall carbon nanotubes

    SciTech Connect

    Fedoseeva, Yu. V.; Bulusheva, L. G.; Okotrub, A. V.; Vyalikh, D. V.; Fonseca, A.

    2010-12-14

    Effect of Ar{sup +} ion irradiation on the structure of pristine and fluorinated single-wall carbon nanotubes (SWCNTs) was examined using transmission electron microscopy (TEM), Raman, and x-ray photoelectron spectroscopy (XPS). The TEM analysis revealed retention of tubular structures in both irradiated samples while Raman spectroscopy and XPS data indicated a partial destruction of nanotubes and formation of oxygen-containing groups on the nanotube surface. From similarity of electronic states of carbon in the irradiated pristine and fluorinated SWCNTs observed by XPS, it was suggested that defluorination of nanotubes proceeded with breaking of C-F bonds.

  17. Influence of Single-Walled Carbon Nanotubes on Thermal Expansion of Water

    NASA Astrophysics Data System (ADS)

    Korolovych, V. F.; Bulavin, L. A.; Prylutskyy, Yu. I.; Khrapatiy, S. V.; Tsierkezos, N. G.; Ritter, U.

    2014-01-01

    This article reports the results of an investigation of the influence of single-walled carbon nanotubes (SWCNTs) functionalized with carboxyl groups on PVT data of water. Specifically, the impact of an aqueous suspension of SWCNTs (maximum concentration of 3.0 mg mL) on the isobaric thermal expansion of water in the temperature and pressure ranges of 293 K to 342 K and 0.1 MPa to 152.3 MPa, respectively, was investigated. The obtained results are discussed in terms of different structures of water confined inside and outside SWCNTs.

  18. Electronic durability of flexible transparent films from type-specific single-wall carbon nanotubes.

    PubMed

    Harris, John M; Iyer, Ganjigunte R Swathi; Bernhardt, Anna K; Huh, Ji Yeon; Hudson, Steven D; Fagan, Jeffrey A; Hobbie, Erik K

    2012-01-24

    The coupling between mechanical flexibility and electronic performance is evaluated for thin films of metallic and semiconducting single-wall carbon nanotubes (SWCNTs) deposited on compliant supports. Percolated networks of type-purified SWCNTs are assembled as thin conducting coatings on elastic polymer substrates, and the sheet resistance is measured as a function of compression and cyclic strain through impedance spectroscopy. The wrinkling topography, microstructure and transparency of the films are independently characterized using optical microscopy, electron microscopy, and optical absorption spectroscopy. Thin films made from metallic SWCNTs show better durability as flexible transparent conductive coatings, which we attribute to a combination of superior mechanical performance and higher interfacial conductivity. PMID:22148890

  19. Surface chemical functionalized single-walled carbon nanotube with anchored phenol structures: Physical and chemical characterization

    NASA Astrophysics Data System (ADS)

    Bae, Jong Hyun; Shanmugharaj, A. M.; Noh, Woo Hyun; Choi, Won Seok; Ryu, Sung Hun

    2007-02-01

    Surface functionalization of single-walled carbon nanotube was carried out by introducing ylides groups containing anchored phenol structures. The functionalized nanotube is characterized using elemental analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, Raman spectroscopy and zeta potential measurements. Elemental and FT-IR analysis reveal the successful functionalization of azomethine ylides. Raman spectroscopic studies corroborates that the surface functionalization does not affect the basic crystal domain size of the nanotubes. Functionalized carbon nanotubes exhibit higher zeta potential values showing its higher dispersant ability in water and acetone solvent in comparison to pure carbon nanotube.

  20. Silicon carbide at nanoscale: Finite single-walled to "infinite" multi-walled tubes

    NASA Astrophysics Data System (ADS)

    Adhikari, Kapil

    A systematic ab initio study of silicon carbide (SiC) nanostructures, especially finite single-walled, infinite double- and multi-walled nanotubes and nanocones is presented. Electronic and structural properties of all these nanostructures have been calculated using hybrid density functionals (B3LYP and PBE0) as implemented in the GAUSSIAN 03/09 suite of software. The unusual dependence of band gap of silicon carbide nanotubes (SiCNT) has been explained as a direct consequence of curvature effect on the ionicity of the bonds. The study of fullerene hemisphere capped, finite SiC nanotubes indicates that the carbon-capped SiC nanotubes are energetically more preferred than silicon-capped finite or hydrogen terminated infinite nanotubes. Capping a nanotube by fullerene hemisphere reduces its band gap. SiC nanocones have also been investigated as possible cap structures of nanotubes. Electronic properties of the nanocones are found to be strongly dependent upon their tip and edge structures, with possible interesting applications in surface science. Three types of double-walled SiCNTs (n, n)@(m, m) (3 ≤ n ≤ 6 ; 7 ≤ m ≤ 12) have been studied using the finite cluster approximation. The stabilities of these nanotubes are of the same order as those of the single-walled SiC nanotubes and it should be experimentally possible to synthesize both single-walled and double-walled SiC nanotubes. The binding energy per atom or the cohesive energy of the double-walled nanotubes depends not only on the number of atoms but also on the coupling of the constituent single-walled nanotubes and their types. A study of binding energies, Mulliken charges, density of states and HOMO-LUMO gaps has been performed for all nanotubes from (n, n)@(n+3,n+3) to (n, n)@(n+6, n+6) (n=3-6). Evolution of band gaps of the SiCNTs with increase in the number of walls has also been investigated. The nature of interaction between transition metal atoms and silicon carbide nanotubes with different

  1. A Facile High-speed Vibration Milling Method to Water-disperse Single- walled Carbon Nanohorns

    SciTech Connect

    Shu, Chunying; Zhang, Jianfei; Sim, Jae Hyun; Burke, Brian; Williams, Keith A; Rylander, Nichole M; Campbell, Tom; Puretzky, Alexander A; Rouleau, Christopher M; Geohegan, David B; More, Karren Leslie; Esker, Alan R; Gibson, Harry W; Dorn, Harry C

    2010-01-01

    A high-speed vibration milling (HSVM) method was applied to synthesize water dispersible single- walled carbon nanohorns (SWNHs). Highly reactive free radicals (HOOCCH2CH2 ) produced from an acyl peroxide under HSVM conditions react with hydrophobic SWNHs to produce a highly water dispersible derivative (f-SWNHs), which has been characterized in detail by spectroscopic and microscopic techniques together with thermogravimetric analysis (TGA) and dynamic light scatter- ing (DLS). The carboxylic acid functionalized, water-dispersible SWNHs material are versatile precursors that have potential applications in the biomedical area.

  2. Temperature dependence of plasmon resonance in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Morimoto, Takahiro; Ichida, Masao; Ikemoto, Yuka; Okazaki, Toshiya

    2016-05-01

    The temperature dependence of the optical response in the far-infrared (FIR) region of metallic and semiconducting rich single-walled carbon nanotubes (SWCNTs) was investigated by micro-Fourier transform infrared spectrometry with a focused beam of synchrotron radiation. The temperature dependence of the FIR spectra of both types of SWCNT showed negligibly small variations within a wide temperature range from 4 to 300 K. Upon comparison with a theoretical model for the diffusive region, it is speculated that these results might have been caused by a strong suppression of phonon scattering in relatively short CNTs with lengths of less than 1 μm.

  3. Fast Characterization of Magnetic Impurities in Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Chen, Feng; Xue, Y. Y.; Hadijiev, Viktor G.; Chu, C. W.; Nikolaev, Pasha; Arepalli, Sivaram

    2003-01-01

    We have demonstrated that the magnetic susceptibility measurement is a non-destructive, fast and accurate method to determine the residual metal catalysts in a few microgram single-wall carbon nanotube (SWCNT) sample. We have studied magnetic impurities in raw and purified SWCNT by magnetic susceptibility measurements, transmission electron microscopy, and thermogravimetry. The data suggest that the saturation magnetic moment and the effective field, which is caused by the interparticle interactions, decreases and increases respectively with the decrease of the particle size. Methods are suggested to overcome the uncertainty associated.

  4. Transmission electron microscopy observations of fracture of single-wall carbon nanotubes under axial tension

    NASA Astrophysics Data System (ADS)

    Lourie, O.; Wagner, H. D.

    1998-12-01

    Well-aligned bundles of single-wall carbon nanotubes under tensile stresses were observed to fracture in real-time by transmission electron microscopy. The expansion of elliptical holes in the polymer matrix results in a tensile force in bridging nanotubes. The polymer matrix at both ends of the bundles deforms extensively under the tension force, and fracture of the nanotubes occurs in tension within the polymer hole region rather than in shear within the gripping polymer region at the ends of the bundles. This provides evidence of significant polymer-nanotube wetting and interfacial adhesion.

  5. Determination of electronic states of individually dissolved ( n, m) single-walled carbon nanotubes in solution

    NASA Astrophysics Data System (ADS)

    Tanaka, Yasuhiko; Hirayama, Kohei; Niidome, Yasuro; Nakashima, Naotoshi

    2009-11-01

    Solution redox chemistry is useful to understand the chirality-dependent electronic properties of single-walled carbon nanotubes (SWNTs). We have found that the electron transfer reactions of sodium dithionite with SWNTs cause photoluminescence (PL) quenching processes of 14 individually dissolved SWNTs in an aqueous micellar solution. Based on the analysis using the Nernst equation for the PL change, we have determined the conduction band ( c1) levels of the 14 isolated SWNTs. We have also estimated the valence band ( ν1) levels as well as the Fermi levels of the SWNTs using the reported bandgap values of the corresponding isolated SWNTs.

  6. High structural stability of single wall carbon nanotube under quasi-hydrostatic high pressures

    NASA Astrophysics Data System (ADS)

    Chen, Jing-Yin; Kim, Minseob; Yoo, Choong-Shik

    2009-09-01

    In quasi-hydrostatic conditions, single wall carbon nanotubes (SWNTs) exhibit high structural stability to ˜35 GPa, well beyond the stability of sp2 C dbnd C bonds in graphite, carbon fullerenes, benzene, and other hydrocarbons. The pressure-induced Raman changes of SWNT are completely reversible below 16 GPa, partially reversible between 16 and 35 GPa, and irreversible beyond 35 GPa where it turns into highly disordered graphite. We explain the high stability in terms of the pressure-induced structural modification to an interlinked configuration, which occurs reversibly under substantial sp3 hybridization (˜20%) and, thus, increases the stability of sp2 C dbnd C bonds in the SWNTs.

  7. Temperature effects in the Raman spectra of bundled single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Meletov, K. P.; Krestinin, A. V.; Arvanitidis, J.; Christofilos, D.; Kourouklis, G. A.

    2009-08-01

    Bundled single-walled carbon nanotubes (SWCNTs) were studied as a function of temperature by means of Raman spectroscopy. The Raman modes exhibit negative temperature shift, reversible for the G band and partially irreversible for the radial breathing modes (RBMs). The softening of the latter is larger for larger diameter tubes, resulting in a better separation of the RBMs after high temperature treatment (HTT). The RBM residual softening vs. treatment temperature demonstrates threshold-like behavior. The temperature-induced changes may be associated with an irreversible weakening of the tube-tube (intertube) interaction possibly due to adsorbent removal or destruction of random intertube C-C bonds.

  8. Electronic properties of mechanically induced kinks in single-walled carbon nanotubes

    SciTech Connect

    Bozovic, Dolores; Bockrath, M.; Hafner, Jason H.; Lieber, Charles M.; Park, Hongkun; Tinkham, M.

    2001-06-04

    We have used an atomic-force microscope tip to mechanically buckle single-walled carbon nanotubes. The resistance of the induced defects ranged from 10 to 100 k{Omega} and varied with the local Fermi level, as determined by scanned-gate microscopy. By forming two closely spaced defects on metallic nanotubes, we defined quantum dots less than 100 nm in length. These devices exhibited single-electron charging behavior at temperatures up to {similar_to}165 K. {copyright} 2001 American Institute of Physics.

  9. Diameter-dependent bending dynamics of single-walled carbon nanotubes in liquids

    PubMed Central

    Fakhri, Nikta; Tsyboulski, Dmitri A.; Cognet, Laurent; Weisman, R. Bruce; Pasquali, Matteo

    2009-01-01

    By relating nanotechnology to soft condensed matter, understanding the mechanics and dynamics of single-walled carbon nanotubes (SWCNTs) in fluids is crucial for both fundamental and applied science. Here, we study the Brownian bending dynamics of individual chirality-assigned SWCNTs in water by fluorescence microscopy. The bending stiffness scales as the cube of the nanotube diameter and the shape relaxation times agree with the semiflexible chain model. This suggests that SWCNTs may be the archetypal semiflexible filaments, highly suited to act as nanoprobes in complex fluids or biological systems. PMID:19706503

  10. Scanning gate microscopy of electronic inhomogeneities in single-walled carbon nanotube (SWCNT) devices

    NASA Astrophysics Data System (ADS)

    Hunt, Steven R.; Collins, Phillip G.

    2010-03-01

    The electronic properties of graphitic carbon devices are primarily determined by the contact metal and the carbon band structure. However, inhomogeneities such as substrate imperfections, surface defects, and mobile contaminants also contribute and can lead to transistor-like behaviors. We experimentally investigate this phenomena in the 1-D limit using metallic single-walled carbon nanotubes (SWCNTs) before and after the electrochemical creation of sidewall defects. While scanning gate microscopy readily identifies the defect sites, the energy-dependence of the technique allows quantitative analysis of the defects and discrimination of different defect types. This research is partly supported by the NSF (DMR 08-xxxx).

  11. Selective interaction of a soluble pentacene derivative with metallic single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Liu, Cai-Hong; Liu, Yi-Yang; Zhang, Yong-Hui; Wei, Rui-Rui; Li, Bing-Rui; Zhang, Hao-Li; Chen, Yong

    2009-03-01

    We report a soluble pentacene derivative, 6,13-bis(2-(trimethylsilyl)ethynyl)pentacene, can be used for efficient extraction of metallic single-walled carbon nanotubes (SWCNTs), which is proven by resonance Raman spectroscopy (RRS), Vis-NIR absorption spectroscopy and conductivity measurements. RRS studies reveal that the separation is solvent-dependent and is more efficient for small diameter tubes. Theoretical simulation suggests that the adsorption of pentacene on (7, 7) metallic SWCNT is about 34% more favorable than that on (13, 0) semiconducting SWCNT. This work provides a new direction in seeking reagents to facilitate high efficiency and nondestructive separation of metallic and semiconducting SWCNTs.

  12. Molecular dynamics simulation for flow characteristics in nanochannels and single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yasuoka, H.; Imae, T.; Kaneda, M.; Suga, K.

    2014-08-01

    Flows in graphite-, diamond- and silicon-walled nanochannels are discussed by performing molecular dynamics simulations. Flows in carbon nanotubes (CNTs) and graphene- walled nanochannels are also investigated. It is found that the flow rate in the graphite-walled channel tends to be the largest because of its slippery wall structure by the short bond length and the high molecular density of the CNTs. The flow rate in the single walled CNT at a very narrow diameter tends to increase although such a tendency is not seen in the graphene-walled channel.

  13. Nano-Plasticity of Single-Wall Carbon Nanotubes Under Uniaxial Compression

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Menon, Madu; Cho, Kyeongjae

    1999-01-01

    Nano-plasticity of thin single-wall carbon nanotubes under uniaxial compression is investigated through generalized tight-binding molecular dynamics (GTBMD) and ab-initio electronic structure methods. A novel mechanism of nano-plasticity of carbon nanotubes under uniaxial compression is observed in which bonding geometry collapses from a graphitic (sp(sup 2)) to a localized diamond like (sp(sup 3)) reconstruction. The computed critical stress (approximately equals 153 G Pa) and the shape of the resulting plastic deformation is in good agreement with recent experimental observation of collapse and fracture of compressed carbon nanotubes in polymer composites.

  14. Transparent and flexible high-performance supercapacitors based on single-walled carbon nanotube films

    NASA Astrophysics Data System (ADS)

    Kanninen, Petri; Dang Luong, Nguyen; Hoang Sinh, Le; Anoshkin, Ilya V.; Tsapenko, Alexey; Seppälä, Jukka; Nasibulin, Albert G.; Kallio, Tanja

    2016-06-01

    Transparent and flexible energy storage devices have garnered great interest due to their suitability for display, sensor and photovoltaic applications. In this paper, we report the application of aerosol synthesized and dry deposited single-walled carbon nanotube (SWCNT) thin films as electrodes for an electrochemical double-layer capacitor (EDLC). SWCNT films exhibit extremely large specific capacitance (178 F g‑1 or 552 μF cm‑2), high optical transparency (92%) and stability for 10 000 charge/discharge cycles. A transparent and flexible EDLC prototype is constructed with a polyethylene casing and a gel electrolyte.

  15. Quantum Ion-Acoustic Oscillations in Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Khan, S. A.; Iqbal, Z.; Wazir, Z.; Aman-ur-Rehman

    2016-05-01

    Quantum ion-acoustic oscillations in single-walled carbon nanotubes are studied by employing a quantum hydrodynamics model. The dispersion equation is obtained by Fourier transformation, which exhibits the existence of quantum ion-acoustic wave affected by change of density balance due to presence of positive or negative heavy species as stationary ion clusters and wave potential at equilibrium. The numerical results are presented, and the role of quantum degeneracy, nanotube geometry, electron exchange-correlation effects, and concentration and polarity of heavy species on wave dispersion is pointed out for typical systems of interest.

  16. Midgap luminescence centers in single-wall carbon nanotubes created by ultraviolet illumination

    NASA Astrophysics Data System (ADS)

    Iakoubovskii, Konstantin; Minami, Nobutsugu; Kim, Yeji; Miyashita, Kanae; Kazaoui, Said; Nalini, Balakrishnan

    2006-10-01

    The authors report the effect of ultraviolet (UV) illumination on optical properties of single-wall carbon nanotubes (SWCNTs) isolated using various dispersants. It is demonstrated that even weak UV light (˜1mW/cm2) can irreversibly alter the SWCNT structure, thus resulting in the emergence of hitherto unknown, redshifted photoluminescence (PL) peaks with concomitant reduction in some of the original PL peaks. These UV-induced changes are characterized in detail and attributed to the creation of midgap PL centers.

  17. Self-assembly of subnanometer-diameter single-wall MoS2 nanotubes.

    PubMed

    Remskar, M; Mrzel, A; Skraba, Z; Jesih, A; Ceh, M; Demsar, J; Stadelmann, P; Levy, F; Mihailovic, D

    2001-04-20

    We report on the synthesis, structure, and self-assembly of single-wall subnanometer-diameter molybdenum disulfide tubes. The nanotubes are up to hundreds of micrometers long and display diverse self-assembly properties on different length scales, ranging from twisted bundles to regularly shaped "furry" forms. The bundles, which contain interstitial iodine, can be readily disassembled into individual molybdenum disulfide nanotubes. The synthesis was performed using a novel type of catalyzed transport reaction including C(60) as a growth promoter. PMID:11313488

  18. Ferromagnetic properties of single-walled carbon nanotubes synthesized by Fe catalyst arc discharge

    NASA Astrophysics Data System (ADS)

    Ha, Byeongchul; Yeom, Tae Ho; Lee, Soo Hyung

    2009-05-01

    Single-walled carbon nanotubes (SWCNTs) were directly synthesized by a hydrogen arc discharge method using only Fe catalyst. The synthesized carbon materials indicated high-purity SWCNTs with Fe catalyst encapsulated with several graphite layers. The diameter of Fe catalysts encapsulated with graphene layers is 1.5-2.0 nm. From the ferromagnetic resonance measurements, the as-synthesized SWCNTs show the ferromagnetic properties at room temperature. The ferromagnetic properties of SWCNTs would be attributed to Fe catalysts encapsulated by graphite layers.

  19. Step-edge faceting and local metallization of a single-wall semiconducting carbon nanotube

    NASA Astrophysics Data System (ADS)

    Clair, Sylvain; Kim, Yousoo; Kawai, Maki

    2011-10-01

    The adsorption of a single-wall carbon nanotube on a well-defined metal surface produces substantial mutual interaction that can lead to strong effects both on the nanotube and on the substrate side. We report two kinds of step faceting on Au(111) and Cu(111). We observed local metallization of a semiconducting nanotube induced by the deformation pressure of crossing a step edge on Cu(111). The origin of this effect is discussed. Our results illustrate the complexity and the large number of situations encountered for the nanotube-on-metal system.

  20. Synthesis and catalytic activity of heteroatom doped metal-free single-wall carbon nanohorns.

    PubMed

    Wu, Xiaohui; Cui, Longbin; Tang, Pei; Hu, Ziqi; Ma, Ding; Shi, Zujin

    2016-04-01

    Boron-, phosphorus-, nitrogen-doped and co-doped single-wall carbon nanohorns were produced using an arc-vaporization method. These as-prepared doped materials consist of uniform isolated nanohorns and exhibit greatly enhanced catalytic capabilities in the reduction reaction of nitrobenzene and a volcano-shape trend between their activities with a B dopant content is found. Moreover, the B-C3 and P-C3 species in doped nanohorns might act as the acidic and basic sites to promote this reaction. PMID:27006980

  1. Dependence of Thermal Conductivity on Thickness in Single-Walled Carbon Nanotube Films.

    PubMed

    Lee, Kyung-Min; Shrestha, Ramesh; Dangol, Ashesh; Chang, Won Seok; Coker, Zachary; Choi, Tae-Youl

    2016-01-01

    Herein, we report experimentally dependence of thermal conductivity on thickness of single walled carbon nanotubes (SWNTs) thin films; the measurements are based on the micropipette thermal sensor technique. Accurate and well resolved measurements of thermal conductivity made by the micropipette sensor showed a correlated behavior of thickness and thermal conductivity of CNT films that thermal conductivity decreased as thickness increased. The thickness dependence is explained by reduction of mean free path (MFP), which is induced by more intertubular junctions in more dense-packed carbon nanotube (CNT) networks; the thicker SWCNT films were revealed to have higher density. PMID:27398564

  2. Thermoelectric properties of single-wall carbon nanotube films: Effects of diameter and wet environment

    NASA Astrophysics Data System (ADS)

    Hayashi, Daisuke; Ueda, Tomohiro; Nakai, Yusuke; Kyakuno, Haruka; Miyata, Yasumitsu; Yamamoto, Takahiro; Saito, Takeshi; Hata, Kenji; Maniwa, Yutaka

    2016-02-01

    The Seebeck coefficient S and the electrical resistivity ρ of single-wall carbon nanotube (SWCNT) films were investigated as a function of the SWCNT diameter and carrier concentration. The S and ρ significantly changed in humid environments through p-type carrier doping. Experiments, combined with theoretical simulations based on the non-equilibrium Green’s function theory, indicated that the power factor P can be increased threefold by the enrichment of semiconducting SWCNTs, but the nanotube diameter has little effect. The improvement of the film resistivity strongly enhances the film thermoelectric performance, manifested as increasing the value of P above 1200 µW/(m·K2).

  3. Self-assemblies of cationic porphyrins with functionalized water-soluble single-walled carbon nanotubes.

    PubMed

    Kubát, Pavel; Lang, Kamil; Jandal, Pavel; Frank, Ota; Matulková, Irena; Sýkora, Jan; Civis, Svatopluk; Hof, Martin; Kavan, Ladislav

    2009-10-01

    5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin, 5,10,15,20-tetrakis(2-N-methylpyridyl)porphyrin, and 5,10,15,20-tetrakis(4-trimethylammoniophenyl)porphyrin form self-assemblies with single-walled carbon nanotubes (SWNT) functionalized by polyaminobenzene sulfonic acid. Both steady-state and time-resolved emission studies revealed efficient quenching of the excited singlet states of the porphyrins. Atomic force microscopy, fluorescence confocal microscopy, and fluorescence lifetime imaging allowed the visualization of individual bundles of SWNTs and the differentiation of porphyrin molecules at specific binding sites of SWNT. PMID:19908455

  4. Microwave-induced electrophilic addition of single-walled carbon nanotubes with alkylhalides

    NASA Astrophysics Data System (ADS)

    Xu, Yang; Wang, Xianbao; Tian, Rong; Li, Shaoqing; Wan, Li; Li, Mingjian; You, Haijun; Li, Qin; Wang, Shimin

    2008-02-01

    We report the microwave-induced electrophilic addition of single-walled carbon nanotubes (SWNTs) with alkylhalides using Lewis acid as a catalyst followed by hydrolysis. The reaction results in the attachment of alkyl and hydroxyl groups to the surface of the nanotubes. This rapid and high-energy microwave radiation is found to be highly efficient for this reaction, which only needs as low as several minutes. The resulting nanotubes were characterized with FTIR, UV-vis-NIR, Raman, TGA, TEM and AFM. It demonstrates that iodo-alkanes show higher reaction activity with SWNTs than chloro- and bromo-alkanes.

  5. The compressive buckling and size effect of single-walled carbon nanotubes

    SciTech Connect

    Sun, Yuzhou Zhu, Yanzhi; Li, Dongxia

    2015-03-10

    A higher-order Bernoulli-Euler beam model is developed to investigate the compressive buckling and size effect of single-walled carbon nanotubes by using a higher-order continuum relationship that has been previously proposed by the present authors. The second-order deformation gradients with respect to the axial direction are also considered, and the beam parameters are obtained by calculating the constitutive response around the circumference. The critical compressive force is analytically provided, and the size effect is studied by estimating the contribution of the higher-order terms.

  6. Transparent and flexible high-performance supercapacitors based on single-walled carbon nanotube films.

    PubMed

    Kanninen, Petri; Luong, Nguyen Dang; Sinh, Le Hoang; Anoshkin, Ilya V; Tsapenko, Alexey; Seppälä, Jukka; Nasibulin, Albert G; Kallio, Tanja

    2016-06-10

    Transparent and flexible energy storage devices have garnered great interest due to their suitability for display, sensor and photovoltaic applications. In this paper, we report the application of aerosol synthesized and dry deposited single-walled carbon nanotube (SWCNT) thin films as electrodes for an electrochemical double-layer capacitor (EDLC). SWCNT films exhibit extremely large specific capacitance (178 F g(-1) or 552 μF cm(-2)), high optical transparency (92%) and stability for 10 000 charge/discharge cycles. A transparent and flexible EDLC prototype is constructed with a polyethylene casing and a gel electrolyte. PMID:27122323

  7. Fabrication and electrical properties of single wall carbon nanotube channel and graphene electrode based transistors arrays

    SciTech Connect

    Seo, M.; Kim, H.; Kim, Y. H.; Yun, H.; McAllister, K.; Lee, S. W.; Na, J.; Kim, G. T.; Lee, B. J.; Kim, J. J.; Jeong, G. H.; Lee, I.; Kim, K. S.

    2015-07-20

    A transistor structure composed of an individual single-walled carbon nanotube (SWNT) channel with a graphene electrode was demonstrated. The integrated arrays of transistor devices were prepared by transferring patterned graphene electrode patterns on top of the aligned SWNT along one direction. Both single and multi layer graphene were used for the electrode materials; typical p-type transistor and Schottky diode behavior were observed, respectively. Based on our fabrication method and device performances, several issues are suggested and discussed to improve the device reliability and finally to realize all carbon based future electronic systems.

  8. Effective permittivity of single-walled carbon nanotube composites: Two-fluid model

    SciTech Connect

    Moradi, Afshin; Zangeneh, Hamid Reza; Moghadam, Firoozeh Karimi

    2015-12-15

    We develop an effective medium theory to obtain effective permittivity of a composite of two-dimensional (2D) aligned single-walled carbon nanotubes. Electronic excitations on each nanotube surface are modeled by an infinitesimally thin layer of a 2D electron gas represented by two interacting fluids, which takes into account different nature of the σ and π electrons. Calculations of both real and imaginary parts of the effective dielectric function of the system are presented, for different values of the filling factor and radius of carbon nanotubes.

  9. Electronic properties of single-walled carbon nanotubes filled with manganese halogenides

    NASA Astrophysics Data System (ADS)

    Kharlamova, M. V.

    2016-09-01

    In this work, single-walled carbon nanotubes (SWCNTs) were filled with manganese chloride and manganese bromide by a capillary filling method. The electronic properties of the filled SWCNTs were investigated by Raman spectroscopy and X-ray photoelectron spectroscopy. It was found that the encapsulated manganese halogenides led to hole doping of the SWCNTs due to the charge transfer from the nanotubes to the encapsulated compounds. The embedded MnCl2 had stronger doping effect on the SWCNTs than MnBr2.

  10. Size effect in the tensile fracture of single-walled carbon nanotubes with defects

    NASA Astrophysics Data System (ADS)

    Yang, M.; Koutsos, V.; Zaiser, M.

    2007-04-01

    Molecular simulation is used to determine the fracture strength of single-walled carbon nanotubes (SWNT) containing different concentrations of randomly distributed point defects. The results are analysed using Weibull statistics, and the dependence of the statistical distribution of fracture strengths on defect concentration is established. Arguments from extreme order statistics are then used to formulate a relationship between the length of SWNT and their fracture strength. The results of this investigation help to explain the large differences between SWNT fracture strengths measured in experiments (13-52 GPa) and those obtained from theoretical calculations assuming defect-free nanotubes (~185 GPa).

  11. Fine Structure of the Low-Frequency Raman Phonon Bands of Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Iliev, M. N.; Litvinchuk, A. P.; Arepalli, S.; Nikolaev, P.; Scott, C. D.

    1999-01-01

    The Raman spectra of singled-wall carbon nanotubes (SWNT) produced by laser and are process were studied between 5 and 500 kappa. The line width vs. temperature dependence of the low-frequency Raman bands between 150 and 200/ cm deviates from that expected for phonon decay through phonon-phonon scattering mechanism. The experimental results and their analysis provided convincing evidence that each of the low-frequency Raman lines is a superposition of several narrower Raman lines corresponding to tubes of nearly the same diameter. The application of Raman spectroscopy to probe the distribution of SWNT by both diameter and chirality is discussed.

  12. Stable double helical iodine chains inside single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yao, Zhen; Liu, Chun-Jian; Lv, Hang; Liu, Bing-Bing

    2016-08-01

    The helicity of stable double helical iodine chains inside single-walled carbon nanotubes (SWCNTs) is studied by calculating the systematic interaction energy. Our results present clear images of stable double helical structures inside SWCNTs. The optimum helical radius and helical angle increase and decrease with increasing diameter, respectively. The tube's diameter plays a leading role in the helicity of encapsulated structures, while the tube's chirality may induce different metastable structures. This study indicates that the observed double helical iodine chains in experiments are not necessarily the optimum structures, but may also be metastable structures.

  13. Detecting the formation of single-walled carbon nanotube rings by photoabsorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Hida, Akira; Suzuki, Takayuki; Ishibashi, Koji

    2016-08-01

    Photoabsorption spectroscopy was conducted on single-walled carbon nanotubes (SWNTs) during the formation of ring structures. The absorption bands observed before starting the formation gradually shifted while broadening in the middle. When they finally disappeared, it was found, via atomic force microscopy observations, that almost all SWNTs were transformed into rings. The spectral changes were assumed to be due to the changes in the electronic states of SWNTs. This idea was supported by the results of an investigation using a scanning tunneling microscope. It could be said that photoabsorption spectroscopy is useful for detecting ring formation in situ.

  14. Pore structure of raw and purified HiPco single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Cinke, Martin; Li, Jing; Chen, Bin; Cassell, Alan; Delzeit, Lance; Han, Jie; Meyyappan, M.

    2002-10-01

    Very high purity single-walled carbon nanotubes (SWNTs) were obtained from HiPco SWNT samples containing Fe particles by a two-step purification process. The raw and purified samples were characterized using high resolution transmission electron microscopy (HRTEM), Raman spectroscopy and thermogravimetric analysis (TGA). The purified sample consists of ˜0.4% Fe and the process does not seem to introduce any additional defects. The N 2 adsorption isotherm studies at 77 K reveal that the total surface area of the purified sample increases to 1587 m 2/g from 567 m 2/g for the raw material, which is the highest value reported for SWNTs.

  15. Periodic alignment of Si quantum dots on hafnium oxide coated single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Olmedo, Mario; Martinez-Morales, Alfredo A.; Liu, Gang; Yengel, Emre; Ozkan, Cengiz S.; Lau, Chun Ning; Ozkan, Mihrimah; Liu, Jianlin

    2009-03-01

    We demonstrate a bottom up approach for the aligned epitaxial growth of Si quantum dots (QDs) on one-dimensional (1D) hafnium oxide (HfO2) ridges created by the growth of HfO2 thin film on single wall carbon nanotubes. This growth process creates a high strain 1D ridge on the HfO2 film, which favors the formation of Si seeds over the surrounding flat HfO2 area. Periodic alignment of Si QDs on the 1D HfO2 ridge was observed, which can be controlled by varying different growth conditions, such as growth temperature, growth time, and disilane flow rate.

  16. Functionalization of single-walled carbon nanotubes with uracil, guanine, thymine and L-alanine

    NASA Astrophysics Data System (ADS)

    Silambarasan, D.; Iyakutti, K.; Vasu, V.

    2014-06-01

    Experimental investigation of functionalization of oxidized single-walled carbon nanotubes (OSWCNTs) with three nucleic acid bases such as uracil, guanine, thymine and one amino acid, L-alanine is carried out. Initially, the SWCNTs are oxidized by acid treatment. Further, the oxidized SWCNTs are effectively functionalized with aforementioned biological compounds by ultrasonication. The diameter of OSWCNTs has increased after the adsorption of biological compounds. The cumulative Π-Π stacking, hydrogen bond and polar interaction are the key factors to realize the adsorption. The amount of adsorption of each biological compound is estimated. The adsorption of guanine is more among all the four biological compounds.

  17. In situ Raman monitoring of single-walled carbon nanotube filling with copper chloride

    NASA Astrophysics Data System (ADS)

    Eremin, Timofei V.; Tonkikh, Alexander A.; Kudryashova, Ekaterina M.

    2016-03-01

    In situ characterization of single-walled carbon nanotubes during their gas-phase filling with copper chloride (CuCl) was performed with Raman spectroscopy. The time dependence of positions and intensities of G, 2D, and radial breathing modes was investigated. It was demonstrated that the adsorption of copper chloride from gas phase on the external and internal surfaces of nanotubes leads to the Raman mode shifting. However, this effect is weaker than in case of formation of one-dimensional CuCl crystals inside nanotubes.

  18. Donor doping of single-walled carbon nanotubes by filling of channels with silver

    SciTech Connect

    Kharlamova, M. V.; Niu, J. J.

    2012-09-15

    The channels of single-walled carbon nanotubes (SWNTs) are filled with metallic silver. The synthesized nanocomposites are studied by Raman spectroscopy and optical absorption spectroscopy, and these data indicate a substantial modification of the electronic structure of the nanotubes upon their filling. Moreover, X-ray photoelectron spectroscopy shows that the incorporation of the metal leads to a change in the work function of SWNTs due to the Fermi level upshift and to the transfer of an electron density from inserted nanoparticles to the nanotube walls. Thus, the filling of the channels with silver results in donor doping of the nanotubes.

  19. Photogenerated Free Carrier Dynamics in Metal and Semiconductor Single-Walled Carbon Nanotube Films

    SciTech Connect

    Beard, M. C.; Blackburn, J. L.; Heben, M. J.

    2008-01-01

    Time-resolved THz spectroscopy (TRTS) is employed to study the photogenerated charge-carrier dynamics in transparent films of single-walled carbon nanotubes (SWNTs). Two films were investigated: a film with 94% semiconducting-type tubes (s-SWNTs) and a film with only 7% s-SWNT and 93% metal-type tubes (m-SWNTs). We conclude that charge-carriers are generated with >60% yields at low light intensities in both films. Free-carriers are generated by a linear exciton dissociation process that occurs within 1 ps and is independent of excitation wavelength or tube type.

  20. Practical considerations for the demonstration of a single walled carbon nanotube actuator

    NASA Astrophysics Data System (ADS)

    Minett, A. I.; Fraysse, J.; Gu, G.; Roth, S.

    2001-11-01

    The conversion of electrical energy into mechanical energy using macro scale sheets of carbon nanotubes (bucky paper) has been shown to exhibit comparable or superior performance to that of human skeletal muscle. This level of performance was not as high as predicted by theoretical calculations. Therefore, working from a bottom-up principle, it is of paramount interest to not only demonstrate a single carbon nanotube actuator, but to gain a better understanding of the process of nanotube actuation. In this paper, practical considerations and approaches to the preparation of suspended single walled carbon nanotube (SWNT) structures and the measurement of actuation force are discussed.

  1. A sonochemical route to single-walled carbon nanotubes under ambient conditions.

    PubMed

    Jeong, Soo-Hwan; Ko, Ju-Hye; Park, Jong-Bong; Park, Wanjun

    2004-12-15

    A chemical route to single-walled carbon nanotubes (SWCNTs) under ambient conditions has been developed. Silica powder was immersed in a mixture solution of ferrocene and p-xylene. After sonication at atmospheric pressure and room temperature, we obtained high-purity SWCNTs. Sonochemical effects may lead to producing high-purity SWCNTs. The process could be readily generalized to synthesize other forms of carbon-based materials, such as fullerenes, multiwalled nanotubes, carbon onions, and diamond, in liquid solution under ambient conditions. PMID:15584730

  2. Kinetics of reactive ion etching upon single-walled carbon nanotubes

    SciTech Connect

    Kato, Toshiaki; Hatakeyama, Rikizo

    2008-01-21

    The remarkable etching reaction of single-walled carbon nanotubes (SWNTs) has been observed in their growth of the parameter-controlled plasma chemical vapor deposition (CVD). The time evolution study of the SWNTs growth leads to establishing a growth equation which can completely express the growth kinetics of SWNTs in the plasma CVD. The growth equation is found to reveal that there are several key parameters which directly affect the etching reaction of SWNTs. Furthermore, such kinetics of the SWNT etching in plasmas can perfectly be explained with a reactive ion etching model.

  3. On the coordination of La3+ by phosphatidylserine.

    PubMed Central

    Petersheim, M; Sun, J

    1989-01-01

    In a recent study by Bentz, J., D. Alford, J. Cohen, and N. Düzgünes (1988. Biophys. J. 53:593-607), La3+ was found to be more effective than Ca2+ in causing nonleaky fusion of phosphatidylserine vesicles. It was proposed that this difference in fusion efficiency may be due, in part, to a difference in coordination of the two cations. That is, Ca2+ was presumed to bind to the lipid phosphate, whereas La3+ was proposed to be coordinated by the serine carboxylate and amine. 31P and 13C NMR results presented here demonstrate that the lanthanides, Tb3+ and La3+, are coordinated by the phosphodiester and carboxylate moieties of phosphatidylserine. Tb3+-Phosphatidylserine optical experiments suggest that the serine amine does not coordinate the lanthanide below pH 10, at least not while the membrane has a net negative surface charge. Although these observations disagree with the structural details proposed by Bentz et al. (1988), they are not in conflict with their general fusion mechanism. The work presented here also demonstrates that La3+ affects the inner surface phosphodiesters differently than those on the outer surface of phosphatidylserine vesicles. The vesicles studied are of an intermediate size, having diameters on the order of 150-200 nm. The cation appears to have a more immediate effect on the packing of the crowded headgroups on the inner surface. Higher levels of bound La3+ on the outer surface may be required to induce the same changes in headgroup conformation. PMID:2720062

  4. Photoinduced Spontaneous Free-Carrier Generation in Semiconducting Single-Walled Carbon Nanotubes

    SciTech Connect

    Park, Jaehong; Reid, Obadiah G.; Blackburn, Jeffrey L.; Rumbles, Garry

    2015-11-04

    The strong quantum confinement and low dielectric screening impart single-walled carbon nanotubes with exciton-binding energies substantially exceeding kBT at room temperature. Despite these large binding energies, reported photoluminescence quantum yields are typically low and some studies suggest that photoexcitation of carbon nanotube excitonic transitions can produce free charge carriers. Here we report the direct measurement of long-lived free-carrier generation in chirality-pure, single-walled carbon nanotubes in a low dielectric solvent. Time-resolved microwave conductivity enables contactless and quantitative measurement of the real and imaginary photoconductance of individually suspended nanotubes. We found that the conditions of the microwave conductivity measurement allow us to avoid the complications of most previous measurements of nanotube free-carrier generation, including tube–tube/tube–electrode contact, dielectric screening by nearby excitons and many-body interactions. At low photon fluence (approximately 0.05 excitons per μm length of tubes), we directly observe free carriers on excitation of the first and second carbon nanotube exciton transitions.

  5. Single-walled carbon nanotube incorporated novel three phase carbon/epoxy composite with enhanced properties.

    PubMed

    Rana, Sohel; Alagirusamy, Ramasamy; Joshi, Mangala

    2011-08-01

    In the present work, single-walled carbon nanotubes were dispersed within the matrix of carbon fabric reinforced epoxy composites in order to develop novel three phase carbon/epoxy/single-walled carbon nanotube composites. A combination of ultrasonication and high speed mechanical stirring at 2000 rpm was used to uniformly disperse carbon nanotubes in the epoxy resin. The state of carbon nanotube dispersion in the epoxy resin and within the nanocomposites was characterized with the help of optical microscopy and atomic force microscopy. Pure carbon/epoxy and three phase composites were characterized for mechanical properties (tensile and compressive) as well as for thermal and electrical conductivity. Fracture surfaces of composites after tensile test were also studied in order to investigate the effect of dispersed carbon nanotubes on the failure behavior of composites. Dispersion of only 0.1 wt% nanotubes in the matrix led to improvements of 95% in Young's modulus, 31% in tensile strength, 76% in compressive modulus and 41% in compressive strength of carbon/epoxy composites. In addition to that, electrical and thermal conductivity also improved significantly with addition of carbon nanotubes. PMID:22103118

  6. Photoinduced spontaneous free-carrier generation in semiconducting single-walled carbon nanotubes

    PubMed Central

    Park, Jaehong; Reid, Obadiah G.; Blackburn, Jeffrey L.; Rumbles, Garry

    2015-01-01

    Strong quantum confinement and low dielectric screening impart single-walled carbon nanotubes with exciton-binding energies substantially exceeding kBT at room temperature. Despite these large binding energies, reported photoluminescence quantum yields are typically low and some studies suggest that photoexcitation of carbon nanotube excitonic transitions can produce free charge carriers. Here we report the direct measurement of long-lived free-carrier generation in chirality-pure, single-walled carbon nanotubes in a low dielectric solvent. Time-resolved microwave conductivity enables contactless and quantitative measurement of the real and imaginary photoconductance of individually suspended nanotubes. The conditions of the microwave conductivity measurement allow us to avoid the complications of most previous measurements of nanotube free-carrier generation, including tube–tube/tube–electrode contact, dielectric screening by nearby excitons and many-body interactions. Even at low photon fluence (approximately 0.05 excitons per μm length of tubes), we directly observe free carriers on excitation of the first and second carbon nanotube exciton transitions. PMID:26531728

  7. Improving Dispersion of Single-Walled Carbon Nanotubes in a Polymer Matrix Using Specific Interactions

    SciTech Connect

    Rasheed, Asif; Dadmun, Mark D; Ivanov, Ilia N; Britt, Phillip F; Geohegan, David B

    2006-01-01

    A novel approach is presented to improve the dispersion of oxidized single-walled carbon nanotubes (SWNTs) in a copolymer matrix by tuning hydrogen-bonding interactions to enhance dispersion. Nanocomposites of single-walled carbon nanotubes and copolymers of styrene and vinyl phenol (PSVPh) with varying vinyl phenol content were produced and examined. The dispersion of the SWNT in the polymer matrix is quantified by optical microscopy and Raman spectroscopy. Raman spectroscopy is also used to investigate preferred interactions between the SWNTs and the copolymers via the shift in the D* Raman band of the SWNTs in the composites. All composites show regions of SWNT aggregates; however, the aggregate size varies with composition of the PSVPh copolymer and the amount of SWNT oxidation. Optimal dispersion of the SWNT is observed in PSVPh with 20% vinyl phenol and oxidized nanotubes, which correlates with spectroscopic evidence that indicates that this system also incorporates the most interactions between SWNT and polymer matrix. These results are in agreement with previous studies that indicate that optimizing the extent of specific interactions between a polymer matrix and nanoscale filler enables the efficient dispersion of the nanofillers.

  8. A thermal formulation for single-wall quenching of transient laminar flames

    SciTech Connect

    Boust, B.; Sotton, J.; Labuda, S.A.; Bellenoue, M.

    2007-05-15

    Improving our knowledge of flame-wall interaction is of relevance to performing near-wall combustion calculations. Quenching distance is to be determined accordingly, as a major parameter of flame quenching. For this purpose, an equation describing the behavior of single-wall flame quenching has been derived from a simplified model of laminar flame-wall interaction. It allows evaluating quenching distance from wall heat flux and mixture properties; a significant advantage of this formula is the absence of any empirical coefficient. To assess its reliability, the results computed with this equation have been compared to experimental data concerning laminar flame-wall interaction. For this purpose, single-wall quenching parameters have been recorded in both head-on and sidewall configurations. Quenching distance and wall heat flux have been measured simultaneously, during the combustion of quiescent methane-air mixtures in a constant-volume vessel. Quenching distance is determined through direct visualization, whereas wall heat flux is processed from the time evolution of wall surface temperature. The equation has been verified over the pressure range 0.05-0.35 MPa in stoichiometric and lean mixtures. It shows good agreement with experimental data at first order, with less than 20% variation. (author)

  9. Toxicology Study of Single-walled Carbon Nanotubes and Reduced Graphene Oxide in Human Sperm

    PubMed Central

    Asghar, Waseem; Shafiee, Hadi; Velasco, Vanessa; Sah, Vasu R.; Guo, Shirui; El Assal, Rami; Inci, Fatih; Rajagopalan, Adhithi; Jahangir, Muntasir; Anchan, Raymond M.; Mutter, George L.; Ozkan, Mihrimah; Ozkan, Cengiz S.; Demirci, Utkan

    2016-01-01

    Carbon-based nanomaterials such as single-walled carbon nanotubes and reduced graphene oxide are currently being evaluated for biomedical applications including in vivo drug delivery and tumor imaging. Several reports have studied the toxicity of carbon nanomaterials, but their effects on human male reproduction have not been fully examined. Additionally, it is not clear whether the nanomaterial exposure has any effect on sperm sorting procedures used in clinical settings. Here, we show that the presence of functionalized single walled carbon nanotubes (SWCNT-COOH) and reduced graphene oxide at concentrations of 1–25 μg/mL do not affect sperm viability. However, SWCNT-COOH generate significant reactive superoxide species at a higher concentration (25 μg/mL), while reduced graphene oxide does not initiate reactive species in human sperm. Further, we demonstrate that exposure to these nanomaterials does not hinder the sperm sorting process, and microfluidic sorting systems can select the sperm that show low oxidative stress post-exposure. PMID:27538480

  10. Electronic structure of single-walled carbon nanotubes inside helical DNA wraps

    NASA Astrophysics Data System (ADS)

    Snyder, Stacy; Rotkin, Slava

    2007-03-01

    Single stranded DNA can helically wrap a single-walled carbon nanotube (SWNT) leading to changes in electronic structure, which is the subject of our study. Other charged polymers may produce band gap modulation similar to that observed for DNA-SWNT complexes. For these hybrids we assume a regular helical wrap, the potential of which breaks the symmetry of the pristine SWNT. Band structure changes are modeled quantum mechanically using the tight binding method together with self-consistent electrostatics. Gap modulation and band structure symmetry-lowering effects may result in variation of the optical spectra, especially for (slightly forbidden) transverse optical transitions. The effect of environmental screening of charges is investigated. Self-consistent electrostatic calculations yield cohesion energy between a charged, regular wrap and a SWNT of the order of tenths of eV per DNA base [1]. [1] Snyder, S. E., and Rotkin, S. V., Polarization Component of Cohesion Energy in Single-Wall Carbon Nanotube-DNA Complexes, JETP Letters 84, 348 (2006).

  11. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    PubMed Central

    2011-01-01

    Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  12. Comparative Dynamics and Sequence Dependence of DNA and RNA Binding to Single Walled Carbon Nanotubes

    PubMed Central

    Landry, Markita P.; Vuković, Lela; Kruss, Sebastian; Bisker, Gili; Landry, Alexandra M.; Islam, Shahrin; Jain, Rishabh; Schulten, Klaus; Strano, Michael S.

    2015-01-01

    Noncovalent polymer-single walled carbon nanotube (SWCNT) conjugates have gained recent interest due to their prevalent use as electrochemical and optical sensors, SWCNT-based therapeutics, and for SWCNT separation. However, little is known about the effects of polymer-SWCNT molecular interactions on functional properties of these conjugates. In this work, we show that SWCNT complexed with related polynucleotide polymers (DNA, RNA) have dramatically different fluorescence stability. Surprisingly, we find a difference of nearly 2500-fold in fluorescence emission between the most fluorescently stable DNA-SWCNT complex, C30 DNA-SWCNT, compared to the least fluorescently stable complex, (AT)7A-(GU)7G DNA-RNA hybrid-SWCNT. We further reveal the existence of three regimes in which SWCNT fluorescence varies nonmonotonically with SWCNT concentration. We utilize molecular dynamics simulations to elucidate the conformation and atomic details of SWCNT-corona phase interactions. Our results show that variations in polynucleotide sequence or sugar backbone can lead to large changes in the conformational stability of the polymer SWCNT corona and the SWCNT optical response. Finally, we demonstrate the effect of the coronae on the response of a recently developed dopamine nanosensor, based on (GT)15 DNA- and (GU)15 RNA-SWCNT complexes. Our results clarify several features of the sequence dependence of corona phases produced by polynucleotides adsorbed to single walled carbon nanotubes, and the implications for molecular recognition in such phases. PMID:26005509

  13. Single-Wall Carbon Nanotube Field Effect Transistors with Non-Volatile Memory Operation

    NASA Astrophysics Data System (ADS)

    Sakurai, Tatsuya; Yoshimura, Takeshi; Akita, Seiji; Fujimura, Norifumi; Nakayama, Yoshikazu

    2006-10-01

    We describe the fabrication and electrical characteristics of single-wall carbon-nanotubes field-effect transistors (CNT-FETs) with a non-volatile memory function using ferroelectric thin films as gate insulators. The ferroelectric-gate CNT-FETs were fabricated using single-wall CNTs synthesized from alcohol by catalytic chemical vapor deposition and sol-gel derived PbZr0.5Ti0.5O3 thin films. The ferroelectric-gate CNT-FETs showed modulation of the drain current with the gate voltage and the threshold voltage shift (memory window) on the drain current-gate voltage characteristics. Moreover, the memory window was saturated around 1.1 V as the gate voltage sweeping range increased. These results indicate that carriers in CNTs are controlled by spontaneous polarization of the ferroelectric films. Because ferroelectrics exhibit complex couplings between their electrical, structural, mechanical, thermal, and optical properties, and because CNTs have unique mechanical and electrical properties, ferroelectric-gate CNT-FETs offer promise as potentially useful nanoelectronics devices not only for non-volatile memory elements but also for high-sensitivity sensors.

  14. Mechanism of Synthesis of Ultra-Long Single Wall Carbon Nanotubes in Arc Discharge Plasma

    SciTech Connect

    Keidar, Michael

    2013-06-23

    In this project fundamental issues related to synthesis of single wall carbon nanotubes (SWNTs), which is relationship between plasma parameters and SWNT characteristics were investigated. Given that among plasma-based techniques arc discharge stands out as very advantageous in several ways (fewer defects, high flexibility, longer lifetime) this techniques warrants attention from the plasma physics and plasma technology standpoint. Both experimental and theoretical investigations of the plasma and SWNTs synthesis were conducted. Experimental efforts focused on plasma diagnostics, measurements of nanostructures parameters, and nanoparticle characterization. Theoretical efforts focused to focus on multi-dimensional modeling of the arc discharge and single wall nanotube synthesis in arc plasmas. It was demonstrated in experiment and theoretically that controlling plasma parameters can affect nanostucture synthesis altering SWNT properties (length and diameter) and leading to synthesis of new structures such as a few-layer graphene. Among clearly identified parameters affecting synthesis are magnetic and electric fields. Knowledge of the plasma parameters and discharge characteristics is crucial for ability to control synthesis process by virtue of both magnetic and electric fields. New graduate course on plasma engineering was introduced into curriculum. 3 undergraduate students were attracted to the project and 3 graduate students (two are female) were involved in the project. Undergraduate student from Historically Black University was attracted and participated in the project during Summer 2010.

  15. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    NASA Astrophysics Data System (ADS)

    Yuan, Hengguang; Hu, Shanglian; Huang, Peng; Song, Hua; Wang, Kan; Ruan, Jing; He, Rong; Cui, Daxiang

    2011-12-01

    Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  16. Structural stability of transparent conducting films assembled from length purified single-wall carbon nanotubes

    SciTech Connect

    J. M. Harris; G. R. S. Iyer; D. O. Simien; J. A. Fagan; J. Y. Huh; J. Y. Chung; S. D. Hudson; J. Obrzut; J. F. Douglas; C. M. Stafford; E. K. Hobbie

    2011-01-01

    Single-wall carbon nanotube (SWCNT) films show significant promise for transparent electronics applications that demand mechanical flexibility, but durability remains an outstanding issue. In this work, thin membranes of length purified single-wall carbon nanotubes (SWCNTs) are uniaxially and isotropically compressed by depositing them on prestrained polymer substrates. Upon release of the strain, the topography, microstructure, and conductivity of the films are characterized using a combination of optical/fluorescence microscopy, light scattering, force microscopy, electron microscopy, and impedance spectroscopy. Above a critical surface mass density, films assembled from nanotubes of well-defined length exhibit a strongly nonlinear mechanical response. The measured strain dependence reveals a dramatic softening that occurs through an alignment of the SWCNTs normal to the direction of prestrain, which at small strains is also apparent as an anisotropic increase in sheet resistance along the same direction. At higher strains, the membrane conductivities increase due to a compression-induced restoration of conductive pathways. Our measurements reveal the fundamental mode of elasto-plastic deformation in these films and suggest how it might be suppressed.

  17. Nickel-cobalt nanoparticles supported on single-walled carbon nanotubes and their catalytic hydrogenation activity.

    PubMed

    Lekgoathi, Mpho D S; Augustyn, Willem G; Heveling, Josef

    2011-08-01

    Single-walled carbon nanotubes were synthesized from graphite using the arc discharge technique. A nickel/yttrium/graphite mixture was used as the catalyst. After purification by sonication in a Triton X-100 solution, nickel-cobalt metal nanoparticles were deposited on the surface of the single-walled carbon nanotubes. The resulting material and/or the nanotubes themselves were characterized by physisorption, Raman spectroscopy, high-resolution transition electron microscopy and X-ray diffraction. Raman spectroscopy indicates that the nanotubes, prepared by the arc discharge technique, are semi-conducting with a diameter centering at 1.4 nm. The average nickel-cobalt particle size is estimated to be in the region of 8 nm. The catalytic activity of the material was examined for the hydrogenation of unsaturated fatty acid methyl esters obtained from avocado oil. The carbon nanotube supported nickel-cobalt particles effectively hydrogenate polyunsaturated methyl linoleate to monounsaturated methyl oleate. In contrast to a conventional nickel on kieselghur catalyst, further hydrogenation of methyl oleate to undesired methyl stearate was not observed. PMID:22103112

  18. Modelling of single walled carbon nanotube cylindrical structures with finite element method simulations

    NASA Astrophysics Data System (ADS)

    Günay, E.

    2016-04-01

    In this study, the modulus of elasticity and shear modulus values of single-walled carbon nanotubes SWCNTs were modelled by using both finite element method and the Matlab code. Initially, cylindrical armchair and zigzag single walled 3D space frames were demonstrated as carbon nanostructures. Thereafter, macro programs were written by the Matlab code producing the space truss for zigzag and armchair models. 3D space frames were introduced to the ANSYS software and then tension, compression and additionally torsion tests were performed on zigzag and armchair carbon nanotubes with BEAM4 element in obtaining the exact values of elastic and shear modulus values. In this study, two different boundary conditions were tested and especially used in torsion loading. The equivalent shear modulus data was found by averaging the corresponding values obtained from ten different nodal points on the nanotube path. Finally, in this study it was determined that the elastic constant values showed proportional changes by increasing the carbon nanotube diameters up to a certain level but beyond this level these values remained stable.

  19. Terahertz Spectroscopy of Individual Single-Walled Carbon Nanotubes as a Probe of Luttinger Liquid Physics.

    PubMed

    Chudow, Joel D; Santavicca, Daniel F; Prober, Daniel E

    2016-08-10

    Luttinger liquid theory predicts that collective electron excitations due to strong electron-electron interactions in a one-dimensional (1D) system will result in a modification of the collective charge-propagation velocity. By utilizing a circuit model for an individual metallic single-walled carbon nanotube as a nanotransmission line, it has been shown that the frequency-dependent terahertz impedance of a carbon nanotube can probe this expected 1D Luttinger liquid behavior. We excite terahertz standing-wave resonances on individual antenna-coupled metallic single-walled carbon nanotubes. The terahertz signal is rectified using the nanotube contact nonlinearity, allowing for a low-frequency readout of the coupled terahertz current. The charge velocity on the nanotube is determined from the terahertz spectral response. Our measurements show that a carbon nanotube can behave as a Luttinger liquid system with charge-propagation velocities that are faster than the Fermi velocity. Understanding what determines the charge velocity in low-dimensional conductors is important for the development of next generation nanodevices. PMID:27439013

  20. Wafer-scale monodomain films of spontaneously aligned single-walled carbon nanotubes.

    PubMed

    He, Xiaowei; Gao, Weilu; Xie, Lijuan; Li, Bo; Zhang, Qi; Lei, Sidong; Robinson, John M; Hároz, Erik H; Doorn, Stephen K; Wang, Weipeng; Vajtai, Robert; Ajayan, Pulickel M; Adams, W Wade; Hauge, Robert H; Kono, Junichiro

    2016-07-01

    The one-dimensional character of electrons, phonons and excitons in individual single-walled carbon nanotubes leads to extremely anisotropic electronic, thermal and optical properties. However, despite significant efforts to develop ways to produce large-scale architectures of aligned nanotubes, macroscopic manifestations of such properties remain limited. Here, we show that large (>cm(2)) monodomain films of aligned single-walled carbon nanotubes can be prepared using slow vacuum filtration. The produced films are globally aligned within ±1.5° (a nematic order parameter of ∼1) and are highly packed, containing 1 × 10(6) nanotubes in a cross-sectional area of 1 μm(2). The method works for nanotubes synthesized by various methods, and film thickness is controllable from a few nanometres to ∼100 nm. We use the approach to create ideal polarizers in the terahertz frequency range and, by combining the method with recently developed sorting techniques, highly aligned and chirality-enriched nanotube thin-film devices. Semiconductor-enriched devices exhibit polarized light emission and polarization-dependent photocurrent, as well as anisotropic conductivities and transistor action with high on/off ratios. PMID:27043199

  1. Photoinduced Spontaneous Free-Carrier Generation in Semiconducting Single-Walled Carbon Nanotubes

    DOE PAGESBeta

    Park, Jaehong; Reid, Obadiah G.; Blackburn, Jeffrey L.; Rumbles, Garry

    2015-11-04

    The strong quantum confinement and low dielectric screening impart single-walled carbon nanotubes with exciton-binding energies substantially exceeding kBT at room temperature. Despite these large binding energies, reported photoluminescence quantum yields are typically low and some studies suggest that photoexcitation of carbon nanotube excitonic transitions can produce free charge carriers. Here we report the direct measurement of long-lived free-carrier generation in chirality-pure, single-walled carbon nanotubes in a low dielectric solvent. Time-resolved microwave conductivity enables contactless and quantitative measurement of the real and imaginary photoconductance of individually suspended nanotubes. We found that the conditions of the microwave conductivity measurement allow us tomore » avoid the complications of most previous measurements of nanotube free-carrier generation, including tube–tube/tube–electrode contact, dielectric screening by nearby excitons and many-body interactions. At low photon fluence (approximately 0.05 excitons per μm length of tubes), we directly observe free carriers on excitation of the first and second carbon nanotube exciton transitions.« less

  2. Toxicology Study of Single-walled Carbon Nanotubes and Reduced Graphene Oxide in Human Sperm.

    PubMed

    Asghar, Waseem; Shafiee, Hadi; Velasco, Vanessa; Sah, Vasu R; Guo, Shirui; El Assal, Rami; Inci, Fatih; Rajagopalan, Adhithi; Jahangir, Muntasir; Anchan, Raymond M; Mutter, George L; Ozkan, Mihrimah; Ozkan, Cengiz S; Demirci, Utkan

    2016-01-01

    Carbon-based nanomaterials such as single-walled carbon nanotubes and reduced graphene oxide are currently being evaluated for biomedical applications including in vivo drug delivery and tumor imaging. Several reports have studied the toxicity of carbon nanomaterials, but their effects on human male reproduction have not been fully examined. Additionally, it is not clear whether the nanomaterial exposure has any effect on sperm sorting procedures used in clinical settings. Here, we show that the presence of functionalized single walled carbon nanotubes (SWCNT-COOH) and reduced graphene oxide at concentrations of 1-25 μg/mL do not affect sperm viability. However, SWCNT-COOH generate significant reactive superoxide species at a higher concentration (25 μg/mL), while reduced graphene oxide does not initiate reactive species in human sperm. Further, we demonstrate that exposure to these nanomaterials does not hinder the sperm sorting process, and microfluidic sorting systems can select the sperm that show low oxidative stress post-exposure. PMID:27538480

  3. Wafer-scale monodomain films of spontaneously aligned single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    He, Xiaowei; Gao, Weilu; Xie, Lijuan; Li, Bo; Zhang, Qi; Lei, Sidong; Robinson, John M.; Hároz, Erik H.; Doorn, Stephen K.; Wang, Weipeng; Vajtai, Robert; Ajayan, Pulickel M.; Adams, W. Wade; Hauge, Robert H.; Kono, Junichiro

    2016-07-01

    The one-dimensional character of electrons, phonons and excitons in individual single-walled carbon nanotubes leads to extremely anisotropic electronic, thermal and optical properties. However, despite significant efforts to develop ways to produce large-scale architectures of aligned nanotubes, macroscopic manifestations of such properties remain limited. Here, we show that large (>cm2) monodomain films of aligned single-walled carbon nanotubes can be prepared using slow vacuum filtration. The produced films are globally aligned within ±1.5° (a nematic order parameter of ∼1) and are highly packed, containing 1 × 106 nanotubes in a cross-sectional area of 1 μm2. The method works for nanotubes synthesized by various methods, and film thickness is controllable from a few nanometres to ∼100 nm. We use the approach to create ideal polarizers in the terahertz frequency range and, by combining the method with recently developed sorting techniques, highly aligned and chirality-enriched nanotube thin-film devices. Semiconductor-enriched devices exhibit polarized light emission and polarization-dependent photocurrent, as well as anisotropic conductivities and transistor action with high on/off ratios.

  4. Composite of single walled carbon nanotube and sulfosalicylic acid doped polyaniline: a thermoelectric material

    NASA Astrophysics Data System (ADS)

    Jana Chatterjee, Mukulika; Banerjee, Dipali; Chatterjee, Krishanu

    2016-08-01

    Nanocomposites containing single walled carbon nanotubes (SWCNTs) and highly ordered polyaniline (PANI) have been synthesized employing an in situ polymerization using different weight percentages of single-walled carbon nanotube (SWCNT) as template and aniline as a reactant. The composites show homogeneously dispersed SWCNTs which are uniformly coated with PANI through a strong interface interaction. Structural characterization shows that the PANI cultivated along the surface of the SWCNTs in an ordered manner during the SWCNT-directed polymerization process. Measurements at room temperature displayed a significant enhancement in both the electrical conductivity and thermoelectric power which could be attributed to the more ordered chain structures of the PANI on SWCNT. As a result, the power factor of the composite is improved which increases with temperature. At the same time, the measured value of thermal conductivity at room temperature being lowest among the reported values, has resulted in best ZT at room temperature. The lowest value of thermal conductivity is attributed to the large phonon scattering due to the introduction of nanointerfaces.

  5. Advances in NO2 sensing with individual single-walled carbon nanotube transistors

    PubMed Central

    Muoth, Matthias; Roman, Cosmin; Haluska, Miroslav; Hierold, Christofer

    2014-01-01

    Summary The charge carrier transport in carbon nanotubes is highly sensitive to certain molecules attached to their surface. This property has generated interest for their application in sensing gases, chemicals and biomolecules. With over a decade of research, a clearer picture of the interactions between the carbon nanotube and its surroundings has been achieved. In this review, we intend to summarize the current knowledge on this topic, focusing not only on the effect of adsorbates but also the effect of dielectric charge traps on the electrical transport in single-walled carbon nanotube transistors that are to be used in sensing applications. Recently, contact-passivated, open-channel individual single-walled carbon nanotube field-effect transistors have been shown to be operational at room temperature with ultra-low power consumption. Sensor recovery within minutes through UV illumination or self-heating has been shown. Improvements in fabrication processes aimed at reducing the impact of charge traps have reduced the hysteresis, drift and low-frequency noise in carbon nanotube transistors. While open challenges such as large-scale fabrication, selectivity tuning and noise reduction still remain, these results demonstrate considerable progress in transforming the promise of carbon nanotube properties into functional ultra-low power, highly sensitive gas sensors. PMID:25551046

  6. Flux-Dependent Growth Kinetics and Diameter Selectivity in Single-Wall Carbon Nanotube Arrays

    SciTech Connect

    Geohegan, David B; Puretzky, Alexander A; Jackson, Jeremy Joseph; Rouleau, Christopher M; Eres, Gyula; More, Karren Leslie

    2011-01-01

    The nucleation and growth kinetics of single-wall carbon nanotubes in aligned arrays have been measured using fast pulses of acetylene and in situ optical diagnostics in conjunction with low pressure chemical vapor deposition (CVD). Increasing the acetylene partial pressure is shown to decrease nucleation times by three orders of magnitude, permitting aligned nanotube arrays to nucleate and grow to microns lengths within single gas pulses at high (up to 7 micron/s) peak growth rates and short ~ 0.5 s times.Low-frequency Raman scattering (> 10 cm-1) and transmission electron microscopy measurements show that increasing the feedstock flux in both continuous-CVD and pulsed-CVD shifts the product distribution to large single-wall carbon nanotube diameters > 2.5 nm. Sufficiently high acetylene partial pressures in pulsed-CVD appear to temporarily terminate the growth of the fastest- growing, small-diameter nanotubes by overcoating the more catalytically-active, smaller catalyst nanoparticles within the ensemble with non-nanotube carbon in agreement with a growth model. The results indicate that subsets of catalyst nanoparticle ensembles nucleate, grow, and terminate growth within different flux ranges according to their catalytic activity.

  7. Single-Wall Carbon Nanotube Production by the Arc Process: A Parametric Study

    NASA Technical Reports Server (NTRS)

    Scott, Carl D.; Gorelik, Olga; Proft, William J.

    2000-01-01

    Single wall carbon nanotubes are produced using the arc discharge process. Graphite anodes are filled with a mixture of nickel and yttrium metallic powders, then vaporized by creating a high current arc. By varying the current, gap distance, and ambient pressure it is shown that the best yield of single wall carbon nanotubes is obtained within a narrow range of conditions. The relative yield and purity of the product are indicated semi-quantitatively from scanning electric microscopy (SEM) and thermogravimetric analysis (TGA). Two types of anodes have been investigated. The first is hollow and filled with a powder mixture of graphite, nickel and yttrium. The second is filled with a paste made of a mixture of metal nitrates, graphite powder and carbon adhesive, then reduced in an argon atmosphere at high temperature. Product purity and yield will be compared for the two types of anodes. The graphite in the anodes may have hydrogen attached in the pores. To remove this impurity anodes have been baked up to 1400 - 1500 C. The effect of baking the anodes on impurities in the product will be given.

  8. Single-walled carbon nanotubes based chemiresistive genosensor for label-free detection of human rheumatic heart disease

    NASA Astrophysics Data System (ADS)

    Singh, Swati; Kumar, Ashok; Khare, Shashi; Mulchandani, Ashok; Rajesh

    2014-11-01

    A specific and ultrasensitive, label free single-walled carbon nanotubes (SWNTs) based chemiresistive genosensor was fabricated for the early detection of Streptococcus pyogenes infection in human causing rheumatic heart disease. The mga gene of S. pyogenes specific 24 mer ssDNA probe was covalently immobilized on SWNT through a molecular bilinker, 1-pyrenemethylamine, using carbodiimide coupling reaction. The sensor was characterized by the current-voltage (I-V) characteristic curve and scanning electron microscopy. The sensing performance of the sensor was studied with respect to changes in conductance in SWNT channel based on hybridization of the target S. pyogenes single stranded genomic DNA (ssG-DNA) to its complementary 24 mer ssDNA probe. The sensor shows negligible response to non-complementary Staphylococcus aureus ssG-DNA, confirming the specificity of the sensor only with S. pyogenes. The genosensor exhibited a linear response to S. pyogenes G-DNA from 1 to1000 ng ml-1 with a limit of detection of 0.16 ng ml-1.

  9. Single-walled carbon nanotubes based chemiresistive genosensor for label-free detection of human rheumatic heart disease

    SciTech Connect

    Singh, Swati; Kumar, Ashok E-mail: ashokigib@rediffmail.com; Khare, Shashi; Mulchandani, Ashok; Rajesh E-mail: ashokigib@rediffmail.com

    2014-11-24

    A specific and ultrasensitive, label free single-walled carbon nanotubes (SWNTs) based chemiresistive genosensor was fabricated for the early detection of Streptococcus pyogenes infection in human causing rheumatic heart disease. The mga gene of S. pyogenes specific 24 mer ssDNA probe was covalently immobilized on SWNT through a molecular bilinker, 1-pyrenemethylamine, using carbodiimide coupling reaction. The sensor was characterized by the current-voltage (I-V) characteristic curve and scanning electron microscopy. The sensing performance of the sensor was studied with respect to changes in conductance in SWNT channel based on hybridization of the target S. pyogenes single stranded genomic DNA (ssG-DNA) to its complementary 24 mer ssDNA probe. The sensor shows negligible response to non-complementary Staphylococcus aureus ssG-DNA, confirming the specificity of the sensor only with S. pyogenes. The genosensor exhibited a linear response to S. pyogenes G-DNA from 1 to1000 ng ml{sup −1} with a limit of detection of 0.16 ng ml{sup −1}.

  10. Super-high-frequency shielding properties of excimer-laser-synthesized-single-wall-carbon-nanotubes/polyurethane nanocomposite films

    SciTech Connect

    Aiessa, B.; Habib, M. A.; Denidni, T. A.; El Khakani, M. A.; Laberge, L. L.; Therriault, D.

    2011-04-15

    Electromagnetic shielding attenuation (ESA) properties of carbon nanotubes/polymer nanocomposite films, in the super high frequency (SHF) X-band (7-12 GHz) domain are studied. The nanocomposite films consisted of thermoset polyurethane (PU) resin blended with single-walled carbon nanotubes (SWCNTs) mats, and deposited on fused quartz substrates. Two different approaches were used to achieve the nanocomposite films, namely (i) through the on-substrate ''all-laser'' growth approach of SWCNTs directly onto substrate, followed by their infiltration by the PU resin, and (ii) by appropriately dispersing the chemically-purified SWCNTs (in the soot form) into the PU matrix and their subsequent deposition onto quartz substrates by means of a solvent casting process. Characterizations of the ESA properties of the developed nanocomposite films show that they exhibit systematically a deep shielding band, centered at around 9.5 GHz, with an attenuation as high as |- 30| dB, recorded for SWCNT loads of 2.5 wt. % and above. A direct correlation is established between the electrical conductivity of the nanocomposite films and their electromagnetic shielding capacity. The SWCNTs/PU nanocomposites developed here are highly promising shielding materials as SHF notch filters, as their ESA capacity largely exceeds the target value of |- 20| dB generally requested for commercial applications.

  11. Single-walled carbon nanotube and graphene: Nano-delivery of Gambogic acid increases its cytotoxicty in various cancer cells

    NASA Astrophysics Data System (ADS)

    Saeed, Lamya M.

    Nanomedicine is a new branch of medicine that has been developed due to the critical need to treat challenging diseases, especially cancer since it remains a significant cause of morbidity and mortality worldwide and the second most common cause of death after heart disease in the USA. One of the most important health care applications of nanomedicine concerns the development of drug delivery systems. Graphene (Gn), an atom-thick carbon monolayer of sp2- bonded carbon atoms arranged in a two dimensional (2D) honeycomb crystal lattice, and single-walled carbon nanotubes (SWCNTs) (1D, tubular) are among the most promising nanomaterials with the capability of delivering drugs or small therapeutic molecules to cancerous cells. For example, they have been used as vehicles for the anti-cancer, low-toxicity drug Gambogic acid (GA). Here, the cytotoxicity of GA in breast (MCF-7), pancreatic (PANC-1), cervical (HELA), ovarian (NCI/ADR), and prostate (PC3) cancer cells was assessed to determine what effect nanodelivery by either Gn or SWCNTs had on the efficacy of this promising drug. The nanomaterials showed no toxicity at the concentrations used. The inhibition of cell proliferation and apoptosis of the cells was due to the effects of GA which was significantly enhanced by nanodelivery. Such delivery of GA by either Gn or SWCNTs represents a first step toward assessing their effectiveness in more complex, targeted nano-delivery in vivo settings and signals their potential application in the treatment of cancer.

  12. Photothermal optical coherence tomography for depth-resolved imaging of mesenchymal stem cells via single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Subhash, Hrebesh M.; Connolly, Emma; Murphy, Mary; Barron, Valerie; Leahy, Martin

    2014-03-01

    The progress in stem cell research over the past decade holds promise and potential to address many unmet clinical therapeutic needs. Tracking stem cell with modern imaging modalities are critically needed for optimizing stem cell therapy, which offers insight into various underlying biological processes such as cell migration, engraftment, homing, differentiation, and functions etc. In this study we report the feasibility of photothermal optical coherence tomography (PT-OCT) to image human mesenchymal stem cells (hMSCs) labeled with single-walled carbon nanotubes (SWNTs) for in vitro cell tracking in three dimensional scaffolds. PT-OCT is a functional extension of conventional OCT with extended capability of localized detection of absorbing targets from scattering background to provide depth-resolved molecular contrast imaging. A 91 kHz line rate, spectral domain PT-OCT system at 1310nm was developed to detect the photothermal signal generated by 800nm excitation laser. In general, MSCs do not have obvious optical absorption properties and cannot be directly visualized using PT-OCT imaging. However, the optical absorption properties of hMSCs can me modified by labeling with SWNTs. Using this approach, MSC were labeled with SWNT and the cell distribution imaged in a 3D polymer scaffold using PT-OCT.

  13. Photosensitized Singlet Oxygen Production upon Two-Photon Excitation of Single-Walled Carbon Nanotubes and Their Functionalized Analogs

    PubMed Central

    Gandra, Naveen; Chiu, Pui Lam; Li, Wenbing; Anderson, Yolanda R.; Mitra, Somenath; He, Huixin; Gao, Ruomei

    2009-01-01

    Single-walled carbon nanotubes (SWNTs) functionalized with -COOH (along with some sulphonation and nitration), and/or modified with chitosan were prepared and tested for their singlet oxygen (1O2) production. The emission from 1O2 observed upon SWNT irradiation at 532 nm was due to a two-photon process, while 1O2 production via excitation at 355 nm occurred through a conventional one-photon pathway. The relative quantum yield of 1O2 production at excitation wavelength of 532 nm was found to be 0.00, 0.07-0.13 and 0.24-0.54 for highly-functionalized, partially-functionalized and non-functionalized SWNT samples respectively. The nanotube-mediated generation of 1O2 may find applications in both targeted destruction of tumor cells and selective degradation of drug molecules. Our research provides a practical approach to modulate the production of reactive oxygen species from SWNTs via surface functionalization/modification. PMID:20046942

  14. Optical and electrical studies of single walled carbon nanotubes for infrared sensing and photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Omari, Mones A.

    Carbon nanotubes are emerging as highly promising opto-electro-mechanical device components essential for the development of a variety of hybrid opto-electronic, electro-mechanical and bio-medical technologies on the nanoscale and have been a subject of continued research. In particular, single-walled carbon nanotubes are predicted to exhibit strong light absorption induced by photon-assisted electronic transitions, free carrier and plasmonic-based absorption. Single-walled carbon nanotubes have been confirmed to exhibit a strong photoconduction response in the infrared range, which can provide many new opportunities in engineering nano-photovoltaic and optoelectronic devices. At the same time, the use of strong chemical reagents has been long considered as one of the key processing steps for the separation and purification of single-walled carbon nanotube post-synthesis. In this work, optically-induced voltage in carbon nanotube bundles and thin-films configured as two-terminal resistive elements and operating as junctionless photo-cells in the infrared range as well as the time-dependent wet-processing of HiPCo nanotubes in phosphoric acid and its effect on the structural, transport, infrared light absorption, and photoconduction characteristics were studied. As the photo-voltage generated is found to appear only for asymmetric and off-contact illuminations, the effect is explained based on a photo-generated heat flow model. The engineered cell prototypes were found to yield electrical powers of ˜ 30 pW while demonstrating improved conversion efficiency under high-flux illumination. The cell is also shown to act as an uncooled infrared sensor, with its dark-to-photocurrent ratio improving as temperature increases. The wet-processing of HiPCo nanotubes was done for a nominal time intervals of 1, 2 and 3 hours. The treatment was found to be a two-step process that initially results in the removal and partial replacement of most pre-existing C-O, O-H and CHx groups

  15. Water Encapsulation Control in Individual Single-Walled Carbon Nanotubes by Laser Irradiation.

    PubMed

    Chiashi, Shohei; Hanashima, Tateki; Mitobe, Ryota; Nagatsu, Kotaro; Yamamoto, Takahiro; Homma, Yoshikazu

    2014-02-01

    Owing to one-dimensionality, nanoscale curvature, and high chemical stability, single-walled carbon nanotubes (SWNTs) have unique surfaces for gas molecules: outer surface as adsorption (exohedral) site and inner surface that provides encapsulation (endohedral) space. Because as-grown SWNTs have different structure (chirality and diameter) and they are normally bundled, it is extremely difficult to investigate the intrinsic properties of SWNTs as adsorbent. Here we demonstrate controlling adsorption and encapsulation states of water in individual suspended SWNTs using laser irradiation with monitoring of their behavior by photoluminescence measurement and perform molecular dynamics simulation. The laser heating and the pressure control make water molecules encapsulated or ejected for SWNTs, which are individually oxidized and opened with laser heating. The precise control of oxidization makes it possible to observe the cluster formation of water molecules during the encapsulation process and to confine water molecules inside SWNTs even in vacuum. PMID:26276583

  16. Multi-Fractal Hierarchy of Single-Walled Carbon Nanotube Hydrophobic Coatings

    PubMed Central

    De Nicola, Francesco; Castrucci, Paola; Scarselli, Manuela; Nanni, Francesca; Cacciotti, Ilaria; De Crescenzi, Maurizio

    2015-01-01

    A hierarchical structure is an assembly with a multi-scale morphology and with a large and accessible surface area. Recent advances in nanomaterial science have made increasingly possible the design of hierarchical surfaces with specific and tunable properties. Here, we report the fractal analysis of hierarchical single-walled carbon nanotube (SWCNT) films realized by a simple, rapid, reproducible, and inexpensive filtration process from an aqueous dispersion, then deposited by drytransfer printing method on several substrates, at room temperature. Furthermore, by varying the thickness of carbon nanotube random networks, it is possible tailoring their wettability due to capillary phenomena in the porous films. Moreover, in order to describe the wetting properties of such surfaces, we introduce a two-dimensional extension of the Wenzel-Cassie-Baxter theory. The hierarchical surface roughness of SWCNT coatings coupled with their exceptional and tunable optical and electrical properties provide an ideal hydrophobic composite surface for a new class of optoelectronic and nanofluidic devices. PMID:25716718

  17. Self-Assembling Peptide Coatings Designed for Highly Luminescent Suspension of Single-Walled Carbon Nanotubes

    PubMed Central

    Tsyboulski, Dmitri A.; Bakota, Erica L.; Witus, Leah S.; Rocha, John-David R.; Hartgerink, Jeffrey D.; Weisman, R. Bruce

    2009-01-01

    A series of self-assembling multidomain peptides have been designed, synthesized, and tested for their ability to individually suspend single-walled carbon nanotubes (SWCNTs) in water while preserving strong near-IR nanotube luminescence. Photometric and spectral measurements on individual SWCNTs revealed that emission in the common biocompatible coating agents Pluronic F127, ss-DNA, and BSA is approximately an order of magnitude weaker than in the bio-incompatible ionic surfactant SDBS. By contrast, one of the engineered peptides gave SWCNT emission ~40% as intense as in SDBS. A strong inverse correlation was also found between the spectral line widths of coated SWCNTs and the efficiency of their emission. Peptides with rationally designed self-assembly properties appear to be promising coatings that may enable SWCNT optical sensing applications in biological environments. PMID:19053447

  18. Predicting excitonic gaps of semiconducting single-walled carbon nanotubes from a field theoretic analysis

    DOE PAGESBeta

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-17

    We demonstrate that a non-perturbative framework for the treatment of the excitations of single walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. Asmore » a result, we test this theory explicitly on the data reported in [NanoLetters 5, 2314 (2005)] and [Phys. Rev. B 82, 195424 (2010)] and so demonstrate the method works over a wide range of reported excitonic spectra.« less

  19. A parametric study of single-wall carbon nanotube growth by laser ablation

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivaram; Holmes, William A.; Nikolaev, Pavel; Hadjiev, Victor G.; Scott, Carl D.

    2004-01-01

    Results of a parametric study of carbon nanotube production by the double-pulse laser oven process are presented. The effect of various operating parameters on the production of single-wall carbon nanotubes (SWCNTs) is estimated by characterizing the nanotube material using analytical techniques, including scanning electron microscopy, transmission electron microscopy, thermo gravimetric analysis and Raman spectroscopy. The study included changing the sequence of the laser pulses, laser energy, pulse separation, type of buffer gas used, operating pressure, flow rate, inner tube diameter, as well as its material, and oven temperature. It was found that the material quality and quantity improve with deviation from normal operation parameters such as laser energy density higher than 1.5 J/cm2, pressure lower than 67 kPa, and flow rates higher than 100 sccm. Use of helium produced mainly small diameter tubes and a lower yield. The diameter of SWCNTs decreases with decreasing oven temperature and lower flow rates.

  20. Evaluation of nonlocal parameter in the vibrations of single-walled carbon nanotubes with initial strain

    NASA Astrophysics Data System (ADS)

    Arash, B.; Ansari, R.

    2010-06-01

    Based upon a nonlocal shell model accounting for the small-scale effects, the vibration characteristics of single-walled carbon nanotubes (SWCNTs) with different boundary conditions subjected to initial strain are studied in this paper. The set of governing equations of motion is numerically solved by a method that emerged from incorporating the radial point interpolation approximation within the framework of the generalized differential quadrature method. The effectiveness of the present nonlocal shell model is assessed by the molecular dynamics simulations as a benchmark of good accuracy. Accordingly, nonlocal parameters for clamped and cantilever SWCNTs with thicknesses of 0.066 and 0.34 nm are proposed due to the uncertainty that exists in defining nanotube wall thickness. The simulation results show that the resonant frequencies of SWCNTs are very sensitive to the initial strain, although small.

  1. Investigation on optical absorption properties of ion irradiated single walled carbon nanotubes

    SciTech Connect

    Vishalli, Dharamvir, Keya; Kaur, Ramneek; Raina, K. K.; Avasthi, D. K.; Jeet, Kiran

    2015-08-28

    In the present study change in the optical absorption properties of single walled carbon nanotubes (SWCNTs) under nickel ion (60 MeV) irradiation at various fluences has been investigated. Langmuir Blodgett technique is used to deposit SWCNT thin film of uniform thickness. AFM analysis shows a network of interconnected bundles of nanotubes. UV-Vis-NIR absorption spectra indicate that the sample mainly contain SWCNTs of semiconducting nature. It has been found in absorption spectra that there is decrease in the intensity of the characteristic SWCNT peaks with increase in fluence. At fluence value 1×10{sup 14} ions/cm{sup 2} there is almost complete suppression of the characteristic SWCNTs peaks.The decrease in the optical absorption with increase in fluence is due to the increase in the disorder in the system which leads to the decrease in optically active states.

  2. Interaction of [FeFe]-Hydrogenases with Single-walled Carbon Nanotubes

    SciTech Connect

    Chang, D. S.; McDonald, T. J.; Kim, Y.-H.; Blackburn, J. L.; Heben, M. J.; King, P. W.

    2007-01-01

    Single-walled carbon nanotubes (SWNT) are promising candidates for use in energy conversion devices as an active photo-collecting elements, for dissociation of bound excitons and charge-transfer from photo-excited chromophores, or as molecular wires to transport charge. Hydrogenases are enzymes that efficiently catalyze the reduction of protons from a variety of electron donors to produce molecular hydrogen. Hydrogenases together with SWNT suggest a novel biohybrid material for direct conversion of sunlight into H{sub 2}. Here, we report changes in SWNT optical properties upon addition of recombinant [FeFe] hydrogenases from Clostridium acetobutylicum and Chlamydomonas reinhardtii. We find evidence that novel and stable charge-transfer complexes are formed under conditions of the hydrogenase catalytic turnover, providing spectroscopic handles for further study and application of this hybrid system.

  3. Acute toxicity of a mixture of copper and single-walled carbon nanotubes to Daphnia magna.

    PubMed

    Kim, Ki T; Klaine, Stephen J; Lin, Sijie; Ke, Pu C; Kim, Sang D

    2010-01-01

    Nanomaterials released into the environment will interact with many materials including other contaminants. This may influence bioavailability and fate of both the nanoparticles and the other contaminants. The present study examined the effect of a combination of soluble copper and surface-modified single-walled carbon nanotubes (SWNTs) on Daphnia magna. Lysophosphatidylcholine (LPC) was used to modify the surface of SWNTs, reducing the surface hydrophobicity of the tubes and thereby producing a stable aqueous nanoparticle suspension. The toxicity of the nanoparticle-copper (Cu) mixture was determined to be additive. The addition of nontoxic concentration of LPC-SWNTs enhanced the uptake and toxicity of copper. Greater amounts of Cu were shown to accumulate in D. magna upon addition of 0.5 and 1.0 mg/L LPC-SWNTs. PMID:20821426

  4. Grafting of Chitosan and Chitosantrimethoxylsilylpropyl Methacrylate on Single Walled Carbon Nanotubes-Synthesis and Characterization

    PubMed Central

    Carson, Laura; Kelly-Brown, Cordella; Stewart, Melisa; Oki, Aderemi; Regisford, Gloria; Stone, Julia; Traisawatwong, Pasakorn; Durand-Rougely, Clarissa; Luo, Zhiping

    2011-01-01

    Acid functionalized single walled carbon nanotubes (CNTs) were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate (TMSPM), hereafter referred to as CNT-chitosan-3-TMSPM. These composites were characterized by Fourier Transform Infrared Resonance Spectroscopy (FTIR), carbon-13 nuclear magnetic resonance (13C NMR), Thermogravimetric Analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite showed improved thermal stability and could be of great potential use in bone tissue engineering. PMID:21765959

  5. Conducting and transparent single-wall carbon nanotube electrodes for polymer-fullerene solar cells

    NASA Astrophysics Data System (ADS)

    Pasquier, Aurelien Du; Unalan, Husnu Emrah; Kanwal, Alokik; Miller, Steve; Chhowalla, Manish

    2005-11-01

    We describe the use of single-wall carbon nanotube (SWNT) thin films as transparent and conducting electrodes for hole collection in poly(hexyl)thiophene-[6-6]phenyl-C61-butyric acid methyl ester (P3HT-PCBM) organic photovoltaics. We report a power conversion efficiency of 1%, with a fill factor of 0.3 and a short-circuit current of 6.5mA/cm2 under 100mW/cm2 polychromatic white light illumination measured in air. These values are comparatively higher than reference cells of similar thickness made on indium tin oxide (ITO) glass substrates. This is attributed to the three-dimensional nature of the interface between the SWNTs and the P3HT-PCBM nanocomposite. Our results indicate that solution processed SWNT thin films are a viable alternative to ITO for photovoltaic devices, eliminating an expensive vacuum deposition step in the fabrication of organic solar cells.

  6. Dysprosium-Catalyzed Growth of Single-Walled Carbon Nanotube Arrays on Substrates

    PubMed Central

    2010-01-01

    In this letter, we report that dysprosium is an effective catalyst for single-walled carbon nanotubes (SWNTs) growth via a chemical vapor deposition (CVD) process for the first time. Horizontally superlong well-oriented SWNT arrays on SiO2/Si wafer can be fabricated by EtOH-CVD under suitable conditions. The structure and properties are characterized by scanning electron microscopy, transition electron microscopy, Raman spectroscopy and atomic force microscopy. The results show that the SWNTs from dysprosium have better structural uniformity and better conductivity with fewer defects. This rare earth metal provides not only an alternative catalyst for SWNTs growth, but also a possible method to generate high percentage of superlong semiconducting SWNT arrays for various applications of nanoelectronic device. PMID:20672139

  7. Cu/single-walled carbon nanotube laminate composites fabricated by cold rolling and annealing

    NASA Astrophysics Data System (ADS)

    Li, Yan-Hui; Housten, William; Zhao, Yimin; Qiu Zhu, Yan

    2007-05-01

    The remarkable mechanical, electrical and thermal properties of single-walled carbon nanotubes (SWCNTs) have attracted extensive research interest as structural and functional materials. In particular, SWCNTs have been used to reinforce polymers and ceramic composites and great progress has been made. For metal matrix composites, the limitation of the conventional manufacturing process and the difficulty in dispersing nanotubes within metal matrices hinder the development of metal matrix composites. In this paper, we demonstrate a successful fabrication of Cu/SWCNT laminate composites by combined techniques of cold rolling and annealing, using 19 layers of large-area SWCNT films sandwiched between 20 layers of Cu thin foils. The tensile strength and Young's modulus of the resultant laminate composites are 361 MPa and 132 GPa, respectively, exhibiting an improvement over the comparative pure Cu foils processed under identical conditions. These results suggest that good interfacial adhesions between nanotubes and the Cu matrix have been achieved after the rolling-annealing-rolling processes.

  8. Toughening of epoxy matrices with reduced single-walled carbon nanotubes.

    PubMed

    Martinez-Rubi, Yadienka; Ashrafi, Behnam; Guan, Jingwen; Kingston, Christopher; Johnston, Andrew; Simard, Benoit; Mirjalili, Vahid; Hubert, Pascal; Deng, Libo; Young, Robert J

    2011-07-01

    Reduced single-walled carbon nanotubes (r-SWCNT) are shown to react readily at room temperature under inert atmosphere conditions with epoxide moieties, such as those in triglycidyl p-amino phenol (TGAP), to produce a soft covalently bonded interface around the SWCNT. The soft interface is compatible with the SWCNT-free cross-linked cured matrix and acts as a toughener for the composite. Incorporation of 0.2 wt % r-SWCNT enhances the ultimate tensile strength, toughness and fracture toughness by 32, 118, and 40%, respectively, without change in modulus. A toughening rate (dK(IC)/dwt(f)) of 200 MPa m(0.5) is obtained. The toughening mechanism is elucidated through dynamic mechanical analyses, Raman spectroscopy and imaging, and stress-strain curve analyses. The method is scalable and applicable to epoxy resins and systems used commercially. PMID:21612292

  9. Electrical and mechanical characterisation of single wall carbon nanotubes based composites for tissue engineering applications.

    PubMed

    Whulanza, Yudan; Battini, Elena; Vannozzi, Lorenzo; Vomero, Maria; Ahluwalia, Arti; Vozzi, Giovanni

    2013-01-01

    This paper presents the realisation of conductive matrices for application to tissue engineering research. We used poly(L-lactide (PLLA)), poly(epsilon-caprolactone) (PCL), and poly(lactide-co-glycolide) (PLGA) as polymer matrix, because they are biocompatible and biodegradable. The conductive property was integrated to them by adding single wall carbon nanotubes (SWNTs) into the polymer matrix. Several SWNTs concentrations were introduced aiming to understand how they influence and modulate mechanical properties, impedance features and electric percolation threshold of polymer matrix. It was observed that a concentration of 0.3% was able to transform insulating matrix into conductive one. Furthermore, a conductive model of the SWNT/polymer was developed by applying power law of percolation threshold. PMID:23646716

  10. Molecular design of strong single-wall carbon nanotube/polyelectrolyte multilayer composites

    NASA Astrophysics Data System (ADS)

    Mamedov, Arif A.; Kotov, Nicholas A.; Prato, Maurizio; Guldi, Dirk M.; Wicksted, James P.; Hirsch, Andreas

    2002-11-01

    The mechanical failure of hybrid materials made from polymers and single-wall carbon nanotubes (SWNT) is primarily attributed to poor matrix-SWNT connectivity and severe phase segregation. Both problems can be successfully mitigated when the SWNT composite is made following the protocol of layer-by-layer assembly. This deposition technique prevents phase segregation of the polymer/SWNT binary system, and after subsequent crosslinking, the nanometre-scale uniform composite with SWNT loading as high as 50 wt% can be obtained. The free-standing SWNT/polyelectrolyte membranes delaminated from the substrate were found to be exceptionally strong with a tensile strength approaching that of hard ceramics. Because of the lightweight nature of SWNT composites, the prepared free-standing membranes can serve as components for a variety of long-lifetime devices.

  11. Photoluminescence Imaging of Oxygen Doped Individual Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Yalcin, Sibel Ebru; Yamaguchi, Hisato; Galande, Charudatta; Crochet, Jared J.; Mohite, Aditya D.; Gupta, Gautam; Ma, Xuedan; Htoon, Han; Doorn, Stephen K.; Los Alamos National Laboratory Collaboration; Rice University Collaboration

    2014-03-01

    Semiconducting single-walled carbon nanotubes (SWNTs) are attractive candidates for near-IR optoelectronic applications. But they show low fluorescence quantum yield. Recent oxygen doping studies have shown that the quantum yield of the excitons can be enhanced by an order of magnitude due to the formation of local 0D sites on the SWNT surface. However, these studies have been limited to ensemble measurements. Understanding the dopant site, exciton migration and trapping dynamics on individual SWNTs is critical for controllably tuning the photo-physical behavior. We have studied ozonated individual (6,5) nanotubes as a function of progressive ozonation. We spatially resolved the pristine and doped state using visible and NIR sensitive cameras. We demonstrate PL imaging as a probe of the emission dynamics as a function of dopant concentration. The spectral studies show the red-shifted emission in the PL of the NTs due to the ozonated site.

  12. Selective electroless coating of palladium nanoparticles on metallic single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Feng, Yiyu; Lv, Peng; Zhang, Xuequan; Li, Yu; Feng, Wei

    2010-08-01

    The selective electroless coating of palladium (Pd) nanoparticles on metallic single-walled carbon nanotube (SWNT) was studied. The remarkable increase in conductivity of SWNT/Pd films up to fourfold higher than pure SWNT was due to p-type doping and Ohmic contact. Metallic behavior of SWNT/Pd-Field effect transistor (on/off ratio=1.2) was attributed to more hole carriers and no electrostatic barrier between nanotube and Pd. G-band and radial breathing mode in Raman indicates a definitive increase in the proportion of metallic SWNT. Results indicate Pd are selectively coated on metallic SWNT with more negative potential allowing for the electroless Pd2+ reduction.

  13. Roll to plate printed stretchable silver electrode using single walled carbon nanotube on elastomeric substrate.

    PubMed

    Jung, Minhun; Noh, Jinsoo; Kim, Junseok; Kim, Donghwan; Cho, Gyoujin

    2013-08-01

    Stretchable electronics may open new applications in display, sensors and actuators. To attain the stretchable electronics, the ink formulation should be compatible with elastomeric substrates. Here, we present the formulation of silver nanoparticles and single walled carbon nanotubes (SWNTs) for printing stretchable silver electrodes on the elastomeric substrates. Highly conductive stretchable electrodes can be printed directly on the poly(styrene-b-butadiene-b-styrene) (PSBS) substrates by roll to plate (R2P) gravure printer. During the stretching test, R2P printed silver based stretchable electrodes show the high conductivity of 1000 S cm(-1) at 0.27 wt% of SWNT loading. Furthermore, the resistance of the printed silver electrode was not changed up to 15% of tensile strain. PMID:23882805

  14. Inkjet-printed stretchable single-walled carbon nanotube electrodes with excellent mechanical properties

    NASA Astrophysics Data System (ADS)

    Kim, Taehoon; Song, Hyunsoo; Ha, Jaeheung; Kim, Sangwoo; Kim, Donghyun; Chung, Seungjun; Lee, Jaemyon; Hong, Yongtaek

    2014-03-01

    Inkjet-printed single-walled carbon nanotube (SWCNT) thin films on stretchable substrates were developed, and their electrical properties were investigated. The 1- and 5-layer printed SWCNT thin films had sheet resistances of 169.76 and 19.08 Ω/sq, respectively, and maintained conductive properties under 100% tensile strain. A nitric acid treatment significantly improved the conductivity of the SWCNT electrodes, and after an initial increase, the 5-layer printed SWCNT electrodes showed a normalized resistance of less than 1.2 after 1000 cycles under 100% tensile strain. The potential of the inkjet-printed SWCNT thin films for stretchable electrode applications was demonstrated via integration with a light-emitting diode.

  15. Light emission and degradation of single-walled carbon nanotube filament

    NASA Astrophysics Data System (ADS)

    Zhao, Z. G.; Li, F.; Liu, C.; Cheng, H. M.

    2005-08-01

    Household light bulbs were fabricated using macroscopically long and aligned single-walled carbon nanotube (SWNT) ropes as filaments. It was found that the SWNT filament could emit bright light when an electric current was passed through it. The light spectrum from the SWNT filament showed a nonblackbody characteristic of the thermal emission, and its infrared emission was almost completely suppressed possibly due to the "photonic band-gap" effect that originates in the loose fibrous bundle structure of the SWNT filament. The electrical resistance of the SWNT filament was found to first increase, and then continually decrease during light emission. It was also found that an electric current could cause degradation and burnout of the SWNT filament and result in complete amorphization, and that an interesting mushroomlike carbon structure was formed due to the carbon evaporation of the nanotube filament during light emission.

  16. Direct Measurement of Polarized Absorption Cross-Section of Single-Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Islam, M. F.; Milkie, D. E.; Kane, C. L.; Yodh, A. Y.; Kikkawa, J. M.

    2004-03-01

    We use a combination of polarized Raman scattering and linear optical absorption to infer optical absorption cross-sections of single-wall carbon nanotube ensembles for visible light co- and cross-polarized with respect to the nanotube axes. These data reveal a strong linear absorption anisotropy, and provide a rapid method by which linear absorption spectra can be used to quantitatively measure the orientation of dispersed nanotubes, even in strongly absorbing media for which Raman approaches are complicated by anisotropic re-absorption processes. Comparison with theory demonstrates that local field depolarization plays a crucial role in affecting optical spectra of the nanotubes. This work supported by NSF through DMR-0203378, DMR-079909 and DGE-0221664, NASA through NAG8-2172, DARPA/ONR through N00014-01-1-0831, and SENS.

  17. Mechanical characterization of suspended strips of meshed single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Li, Bo; Hao, Ji; Jung, Yung Joon; Wan, Kai-tak

    2016-01-01

    A thin film of single walled carbon nanotube (SWCNT) mesh has good potential to integrate the existing electromechanical functions with flexible devices. In this paper, SWCNT mats are transferred to a patterned polymer SU-8 substrate using a wet contact print method, forming a suspended bridge over a groove in the substrate. The front edge of a tipless AFM cantilever loads the suspension at the centerline, causing it to deform into a V-shape by mixed bending and stretching. The mechanical response of load versus AFM displacement is fitted to a linear elastic model to extract the average elastic modulus. Reversible loading-unloading shows little or no permanent damage due to mechanical loads.

  18. Predicting excitonic gaps of semiconducting single-walled carbon nanotubes from a field theoretic analysis

    NASA Astrophysics Data System (ADS)

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-01

    We demonstrate that a nonperturbative framework for the treatment of the excitations of single-walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. We test this theory explicitly on the data reported by Dukovic et al. [Nano Lett. 5, 2314 (2005), 10.1021/nl0518122] and Sfeir et al. [Phys. Rev. B 82, 195424 (2010), 10.1103/PhysRevB.82.195424] and so demonstrate the method works over a wide range of reported excitonic spectra.

  19. Platinum nanoparticles-single-walled carbon nanotubes hybrid based chemiresistive sensor array for myoglobin detection

    NASA Astrophysics Data System (ADS)

    Sharma, Vikash; Puri, Nitin K.; Mulchandani, Ashok; Rajesh

    2016-03-01

    We examined the potential of platinum nanoparticles (PtNP) modified single-walled carbon nanotube (SWNT) hybrid chemiresistive sensor for detection of antigen myoglobin (Mb) in phosphate buffer saline. Protein antibody, Ab-Mb, was covalently immobilized through site specific binding on PtNP attached over SWNT. A concentration-dependent change in the source-drain current of the hybrid device was observed in the range of 0.1-1000 ng ml-1. The hybrid device response fitted well with the Hill-Langmuir equation with a maximum response of 111.14% and low dissociation constant value (K d = 19.98 ng ml-1), indicating high protein antigen binding affinity at hybrid nanostructure.

  20. Controlled functionalization of single-walled carbon nanotubes for enhanced ammonia sensing: a comparative study

    NASA Astrophysics Data System (ADS)

    Datta, K.; Ghosh, P.; More, M. A.; Shirsat, M. D.; Mulchandani, A.

    2012-09-01

    Electrochemically controllable functionalization of single-walled carbon nanotubes (SWNTs) with poly(N-methyl pyrrole) (P[NMP]) is demonstrated for room temperature gas sensing applications. Comparative investigations reveal that the loading content of the functionalization entity has prominent effects on the sensing characteristics of SWNTs. The optimized sensing backbone (P[NMP]-functionalized SWNTs with 5 µC deposited charge) exhibited a lower detection limit of 10 ppb and excellent linearity for a detection window of 10 ppb-01 ppm concentration of NH3. The typical response and recovery time of the optimized sensor is on the order of minutes. Finally, a performance comparison of the P[NMP]-functionalized SWNT sensing backbones with the pristine P[NMP] nanowire sensor ensured the well-defined role of SWNTs in the functionalized structure. The proposed sensing mechanism suggests that the synthesis parameters can be manoeuvered for the highest operational efficiency of the sensors.

  1. Electrical properties of gas sensors based on graphene and single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kondrashov, Ivan I.; Sokolov, Igor V.; Rusakov, Pavel S.; Rybin, Maxim G.; Barmin, Alexander A.; Rizakhanov, Razhudin N.; Obraztsova, Elena D.

    2016-01-01

    Here, we present investigation of the influence of different gases (carbon dioxide, ammonia, and iodine vapor) on the sensory properties of graphene and single-wall carbon nanotube films. The gas molecules are adsorbed by carbon films (graphene or nanotubes) and change the film's electrical resistance. In the course of this work, the setup for studying the electrophysical properties of carbon nanomaterials has been designed and constructed in the lab. With this home-made equipment, we have demonstrated a high efficiency of graphene and nanotubes as adsorbents of different gases and a possibility to use these materials as gas sensors. We have also performed a chemical modification of graphene and carbon nanotubes by attaching the nanoparticles of calcium carbonate (CaCO3) to improve the sensitivity and selectivity of sensors.

  2. Non-radiative Exciton Decay in Single-walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Harrah, Mark; Swan, Anna

    2010-03-01

    Experiments have shown step-wise changes in the fluorescence intensity from single-walled carbon nanotubes [1,2]. It has been proposed that the underlying mechanism for the step-wise changes is diffusion-limited quenching of excitons at defects [1]. This property has been used to demonstrate single-molecule detection for biological applications [3]. We perform a Monte-Carlo simulation of nanotube fluorescence with a diffusion-limited quenching model. The fluorescence intensity is seen to depend on the mean-square distance between defects, implying a nonlinear dependence on the number of defects. The intensity for consecutive defect counts can overlap depending on the positions of the defects. [4pt] [1] Cognet, L. et al. Science 316, 1465-1468 (2007).[0pt] [2] Jin, H. et al. Nano Lett. 8, 4299-4304 (2008).[0pt] [3] Heller, D. A. et al. Nature Nanotech. 4, 114-120 (2009).

  3. Structural and mechanical properties of single-wall carbon nanotube fibers

    SciTech Connect

    Pichot, V.; Albouy, P. A.; Launois, P.; Badaire, S.; Zakri, C.; Poulin, P.

    2006-12-15

    We report quantitative experimental study correlating the structure and mechanical properties of fibers made from single-walled carbon nanotubes (SWNTs) and polyvinyl alcohol (PVA). A post-synthesis solvent drawing treatment is used to vary nanotube alignment, whose detailed understanding is a prerequisite for fiber development. Quantitative analysis of nanotube alignment within the fibers with different draw ratios is performed using x-ray scattering. The method is described in detail, and we also show that the improvement of nanotube alignment with draw ratio can be understood within a model of induced orientation at constant volume. Young's modulus and tensile strength increase with nanotube alignment. This is modeled using continuum mechanics in qualitative agreement with experiment, however quantitative differences show that nanotube alignment is not the only parameter controlling the fiber mechanical properties. We suggest that interaction between the SWNTs and PVA chains should also play a significant role.

  4. XPS Protocol for the Characterization of Pristine and Functionalized Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Sosa, E. D.; Allada, R.; Huffman, C. B.; Arepalli, S.

    2009-01-01

    Recent interest in developing new applications for carbon nanotubes (CNT) has fueled the need to use accurate macroscopic and nanoscopic techniques to characterize and understand their chemistry. X-ray photoelectron spectroscopy (XPS) has proved to be a useful analytical tool for nanoscale surface characterization of materials including carbon nanotubes. Recent nanotechnology research at NASA Johnson Space Center (NASA-JSC) helped to establish a characterization protocol for quality assessment for single wall carbon nanotubes (SWCNTs). Here, a review of some of the major factors of the XPS technique that can influence the quality of analytical data, suggestions for methods to maximize the quality of data obtained by XPS, and the development of a protocol for XPS characterization as a complementary technique for analyzing the purity and surface characteristics of SWCNTs is presented. The XPS protocol is then applied to a number of experiments including impurity analysis and the study of chemical modifications for SWCNTs.

  5. Catalyst size effects on the growth of single-walled nanotubes in neutral and plasma systems

    NASA Astrophysics Data System (ADS)

    Tam, Eugene; Ostrikov, Kostya Ken

    2009-09-01

    The results of large-scale (~109 atoms) numerical simulations of the growth of different-diameter vertically-aligned single-walled carbon nanotubes in plasma systems with different sheath widths and in neutral gases with the same operating parameters are reported. It is shown that the nanotube lengths and growth rates can be effectively controlled by varying the process conditions. The SWCNT growth rates in the plasma can be up to two orders of magnitude higher than in the equivalent neutral gas systems. Under specific process conditions, thin SWCNTs can grow much faster than their thicker counterparts despite the higher energies required for catalyst activation and nanotube nucleation. This selective growth of thin SWCNTs opens new avenues for the solution of the currently intractable problem of simultaneous control of the nanotube chirality and length during the growth stage.

  6. Catalyst size effects on the growth of single-walled nanotubes in neutral and plasma systems.

    PubMed

    Tam, Eugene; Ostrikov, Kostya Ken

    2009-09-16

    The results of large-scale ( approximately 10(9) atoms) numerical simulations of the growth of different-diameter vertically-aligned single-walled carbon nanotubes in plasma systems with different sheath widths and in neutral gases with the same operating parameters are reported. It is shown that the nanotube lengths and growth rates can be effectively controlled by varying the process conditions. The SWCNT growth rates in the plasma can be up to two orders of magnitude higher than in the equivalent neutral gas systems. Under specific process conditions, thin SWCNTs can grow much faster than their thicker counterparts despite the higher energies required for catalyst activation and nanotube nucleation. This selective growth of thin SWCNTs opens new avenues for the solution of the currently intractable problem of simultaneous control of the nanotube chirality and length during the growth stage. PMID:19706955

  7. Aggregated single-walled carbon nanotubes attenuate the behavioural and neurochemical effects of methamphetamine in mice.

    PubMed

    Xue, Xue; Yang, Jing-Yu; He, Yi; Wang, Li-Rong; Liu, Ping; Yu, Li-Sha; Bi, Guo-Hua; Zhu, Ming-Ming; Liu, Yue-Yang; Xiang, Rong-Wu; Yang, Xiao-Ting; Fan, Xin-Yu; Wang, Xiao-Min; Qi, Jia; Zhang, Hong-Jie; Wei, Tuo; Cui, Wei; Ge, Guang-Lu; Xi, Zheng-Xiong; Wu, Chun-Fu; Liang, Xing-Jie

    2016-07-01

    Methamphetamine (METH) abuse is a serious social and health problem worldwide. At present, there are no effective medications to treat METH addiction. Here, we report that aggregated single-walled carbon nanotubes (aSWNTs) significantly inhibited METH self-administration, METH-induced conditioned place preference and METH- or cue-induced relapse to drug-seeking behaviour in mice. The use of aSWNTs alone did not significantly alter the mesolimbic dopamine system, whereas pretreatment with aSWNTs attenuated METH-induced increases in extracellular dopamine in the ventral striatum. Electrochemical assays suggest that aSWNTs facilitated dopamine oxidation. In addition, aSWNTs attenuated METH-induced increases in tyrosine hydroxylase or synaptic protein expression. These findings suggest that aSWNTs may have therapeutic effects for treatment of METH addiction by oxidation of METH-enhanced extracellular dopamine in the striatum. PMID:26974957

  8. Molecular interactions on single-walled carbon nanotubes revealed by high-resolution transmission microscopy

    PubMed Central

    Umeyama, Tomokazu; Baek, Jinseok; Sato, Yuta; Suenaga, Kazu; Abou-Chahine, Fawzi; Tkachenko, Nikolai V.; Lemmetyinen, Helge; Imahori, Hiroshi

    2015-01-01

    The close solid-state structure–property relationships of organic π−aromatic molecules have attracted interest due to their implications for the design of organic functional materials. In particular, a dimeric structure, that is, a unit consisting of two molecules, is required for precisely evaluating intermolecular interactions. Here, we show that the sidewall of a single-walled carbon nanotube (SWNT) represents a unique molecular dimer platform that can be directly visualized using high-resolution transmission electron microscopy. Pyrene is chosen as the π−aromatic molecule; its dimer is covalently linked to the SWNT sidewalls by aryl addition. Reflecting the orientation and separation of the two molecules, the pyrene dimer on the SWNT exhibits characteristic optical and photophysical properties. The methodology discussed here—form and probe molecular dimers—is highly promising for the creation of unique models and provides indispensable and fundamental information regarding molecular interactions. PMID:26173983

  9. TRANSPORT SPECTROSCOPY OF CHEMICAL NANOSTRUCTURES: The Case of Metallic Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Liang, Wenjie; Bockrath, Marc; Park, Hongkun

    2005-05-01

    Transport spectroscopy, a technique based on current-voltage measurements of individual nanostructures in a three-terminal transistor geometry, has emerged as a powerful new tool to investigate the electronic properties of chemically derived nanostructures. In this review, we discuss the utility of this approach using the recent studies of single-nanotube transistors as an example. Specifically, we discuss how transport measurements can be used to gain detailed insight into the electronic motion in metallic single-walled carbon nanotubes in several distinct regimes, depending on the coupling strength of the contacts to the nanotubes. Measurements of nanotube devices in these different conductance regimes have enabled a detailed analysis of the transport properties, including the experimental determination of all Hartree-Fock parameters that govern the electronic structure of metallic nanotubes and the demonstration of Fabry-Perot resonators based on the interference of electron waves.

  10. Improvement of electrical properties of through silicon vias metal interconnector by adding single-walled nanotubes

    NASA Astrophysics Data System (ADS)

    Geon Jung, Dong; Sung, Byung Mok; Kong, Seong Ho

    2015-06-01

    A novel through silicon via (TSV) interconnector, which consists of tin (Sn) powder and single-walled nanotube (SWNT) powder, is proposed and characterized. Most conventional TSV structures, which are commercially available to integrate multiple chips on one packaging, utilize electroplated copper as the interconnector. However, the electroplating-based process has some drawbacks, such as highly demanding fabrication processes in high-aspect-ratio vias, numerous voids, and high cost. To avoid these issues, we used Sn powder mixed with SWNTs as TSV interconnector. SWNTs have been added to improve the electrical properties of TSVs filled only with Sn. The electrical resistance of Sn powder-filled TSVs is 44.59 Ω, but it is markedly decreased to 5 Ω when a Sn and SWNTs mixture (weight ratio of \\text{SWNTs}:\\text{Sn} = 0.5:1) was used as the TSV interconnector. In addition, the proposed method could be used for various applications owing to its low process temperature.

  11. Temperature induced modification of the mid-infrared response of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Shuba, Mikhail V.; Paddubskaya, Alesia G.; Kuzhir, Polina P.; Maksimenko, Sergey A.; Valusis, Gintaras; Poklonski, Nikolai A.; Bellucci, Stefano; Kenanakis, George; Kafesaki, Maria

    2016-03-01

    The temperature dependences of the absorbance spectra of thin free-standing single-walled carbon nanotube (SWCNT) films were studied in the infrared range (700-6200 cm-1) while heating the air from 300 to 575 K. The observed temperature variation in the infrared absorbance spectra has been explained by two different physical factors. The first one is the strong temperature dependence of the conductivity of p-type doped semiconducting SWCNTs. The second one is the temperature dependence of electron relaxation time of intraband electron transitions in metallic SWCNTs. The possibility of the separation of contributions from the interband and intraband transitions to the infrared spectra of SWCNT films has been demonstrated.

  12. Colored semitransparent conductive coatings consisting of monodisperse metallic single-walled carbon nanotubes.

    PubMed

    Green, Alexander A; Hersam, Mark C

    2008-05-01

    Single-walled carbon nanotubes (SWNTs) are promising materials for transparent conduction as a result of their exceptional electrical, optical, mechanical, and chemical properties. However, since current synthetic methods yield polydisperse mixtures of SWNTs, the performance of SWNT transparent conductive films has previously been hindered by semiconducting species. Here, we describe the performance of transparent conductors produced using predominantly metallic SWNTs. Compared with unsorted material, films enriched in metallic SWNTs can enhance conductivity by factors of over 5.6 in the visible and 10 in the infrared. Moreover, by using monodisperse metallic SWNTs sorted with angstrom-level resolution in diameter, semitransparent conductive coatings with tunable optical transmittance can be produced. PMID:18393537

  13. Correlation of Resistance with Fractal Structure for Different Single-walled Carbon Nanotube Networks

    NASA Astrophysics Data System (ADS)

    Liu, Bingbing; Sundqvist, Bertil; Olsson, Eva; Zhu, Xiao-Mei; Zou, Guangtian

    2001-03-01

    The temperature dependence of resistance and magnetoresistance for bulk samples of single-walled nanotubes treated in different ways have been studied systematically and compared with that of pristine nanotubes synthesized with Ce/Ni as catalyst. The resistance of samples pressurized under a hydrostatic pressure of 1.5 GPa shows a 2D Variable range hopping behavior, similar to that for as-grown samples and for samples partly purified by treatment in nitric acid for a short time. A pressed sample composed of small pieces of as-grown mats follows a 3D VRH, similar to that for samples treated in nitric acid for a long time. The correlation between the conduction dimension and the nanotube morphology is well explained by a fractal structure model. The results indicate that 2D VRH is a characteristic transport behavior for nanotubes.

  14. Electron paramagnetic resonance investigation of purified catalyst-free single-walled carbon nanotubes.

    PubMed

    Zaka, Mujtaba; Ito, Yasuhiro; Wang, Huiliang; Yan, Wenjing; Robertson, Alex; Wu, Yimin A; Rümmeli, Mark H; Staunton, David; Hashimoto, Takeshi; Morton, John J L; Ardavan, Arzhang; Briggs, G Andrew D; Warner, Jamie H

    2010-12-28

    Electron paramagnetic resonance of single-walled carbon nanotubes (SWCNTs) has been bedevilled by the presence of paramagnetic impurities. To address this, SWCNTs produced by laser ablation with a nonmagnetic PtRhRe catalyst were purified through a multiple step centrifugation process in order to remove amorphous carbon and catalyst impurities. Centrifugation of a SWCNT solution resulted in sedimentation of carbon nanotube bundles containing clusters of catalyst particles, while isolated nanotubes with reduced catalyst particle content remained in the supernatant. Further ultracentrifugation resulted in highly purified SWCNT samples with a narrow diameter distribution and almost no detectable catalyst particles. Electron paramagnetic resonance (EPR) signals were detected only for samples which contained catalyst particles, with the ultracentrifuged SWCNTs showing no EPR signal at X-band (9.4 GHz) and fields < 0.4 T. PMID:21082779

  15. Photoinduced charge transfer and acetone sensitivity of single-walled carbon nanotube-titanium dioxide hybrids.

    PubMed

    Ding, Mengning; Sorescu, Dan C; Star, Alexander

    2013-06-19

    The unique physical and chemical properties of single-walled carbon nanotubes (SWNTs) make them ideal building blocks for the construction of hybrid nanostructures. In addition to increasing the material complexity and functionality, SWNTs can probe the interfacial processes in the hybrid system. In this work, SWNT-TiO2 core/shell hybrid nanostructures were found to exhibit unique electrical behavior in response to UV illumination and acetone vapors. By experimental and theoretical studies of UV and acetone sensitivities of different SWNT-TiO2 hybrid systems, we established a fundamental understanding on the interfacial charge transfer between photoexcited TiO2 and SWNTs as well as the mechanism of acetone sensing. We further demonstrated a practical application of photoinduced acetone sensitivity by fabricating a microsized room temperature acetone sensor that showed fast, linear, and reversible detection of acetone vapors with concentrations in few parts per million range. PMID:23734594

  16. Ab-initio calculation of n-doped single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Margine, Elena R.; Crespi, Vincent H.

    2004-03-01

    We study charge-induced changes in shape and electronic structure for n-doped single-walled carbon nanotubes within density functional theory. A certain nearly free electron state is downshifted in the presence of extra electrons. A similar effect has been seen in potassium-doped carbon nanotubes [1], where the downshift was attributed to the hybridization of the nearly free electron state with the K 4s state. In the present calculation the negative charge is neutralized by a uniform positive background, so the downshift must arise from a different effect. The state crosses the Fermi level at a charge per carbon atom of 0.04 for all the tubes studied. Connections are made to recent experiments in the group of P. Eklund.[1]Yoshiyuki Miyamoto, Angel Rubio, X. Blase, Marvin L. Cohen, and Steven G. Louie PRL 74, 2993 (1995)

  17. Photophysical properties of zinc phthalocyanine-uridine single walled carbon nanotube - conjugates

    NASA Astrophysics Data System (ADS)

    Ogbodu, Racheal O.; Amuhaya, Edith K.; Mashazi, Philani; Nyokong, Tebello

    2015-10-01

    The photophysical properties of the conjugate of uridine and zinc mono carboxy phenoxy phthalocyanine (ZnMCPPc-uridine, 4) are reported in this work. The conjugate was also adsorbed onto single walled carbon nanotubes (ZnMCPPc-uridine-SWCNT, 5). The X-ray photoelectron spectroscopy of 4 showed three N 1s peaks while that of 5 showed four N 1s peak, a new peak at 399.4 eV of 5 was assigned to pyrrolidonic nitrogen, due to the interaction of the pyrrolic nitrogen of 4 with the oxygen moiety of SWCNT-COOH in 5. The triplet lifetime, triplet and singlet oxygen quantum yields of the zinc mono carboxy phenoxy phthalocyanine increased by over 40% in the presence of uridine. SWCNTs resulted in only a small quenching of the triplet state parameters of 4.

  18. Zipping, entanglement, and the elastic modulus of aligned single-walled carbon nanotube films.

    PubMed

    Won, Yoonjin; Gao, Yuan; Panzer, Matthew A; Xiang, Rong; Maruyama, Shigeo; Kenny, Thomas W; Cai, Wei; Goodson, Kenneth E

    2013-12-17

    Reliably routing heat to and from conversion materials is a daunting challenge for a variety of innovative energy technologies--from thermal solar to automotive waste heat recovery systems--whose efficiencies degrade due to massive thermomechanical stresses at interfaces. This problem may soon be addressed by adhesives based on vertically aligned carbon nanotubes, which promise the revolutionary combination of high through-plane thermal conductivity and vanishing in-plane mechanical stiffness. Here, we report the data for the in-plane modulus of aligned single-walled carbon nanotube films using a microfabricated resonator method. Molecular simulations and electron microscopy identify the nanoscale mechanisms responsible for this property. The zipping and unzipping of adjacent nanotubes and the degree of alignment and entanglement are shown to govern the spatially varying local modulus, thereby providing the route to engineered materials with outstanding combinations of mechanical and thermal properties. PMID:24309375

  19. Dendron growth from vertically aligned single-walled carbon nanotube thin layer arrays for photovoltaic devices.

    PubMed

    Bissett, Mark Alexander; Köper, Ingo; Quinton, Jamie Scott; Shapter, Joe George

    2011-04-01

    Single-walled carbon nanotube arrays attached to conductive transparent electrodes have previously shown promise for use in photovoltaic devices, whilst still retaining light transmission. Here, chemical modification of these thin (<200 nm) arrays with PAMAM-type dendrons has been undertaken to enhance the photoresponse of these devices. The effect of modification on the electrode was measured by differential pulse voltammetry to detect the dendrons, and the effect on the nanotubes was measured by Raman spectroscopy. Solar simulator illumination of the cells was performed to measure the effect of the nanotube modification on the cell power, and determine the optimal modification. Electrochemical impedance spectroscopy was also used to investigate the equivalent electronic circuit elements of the cells. The optimal dendron modification occurred with the second generation (G-2.0), which gave a 70% increase in power over the unmodified nanotube array. PMID:21347484

  20. Charge trapping in aligned single-walled carbon nanotube arrays induced by ionizing radiation exposure

    SciTech Connect

    Esqueda, Ivan S.; Cress, Cory D.; Che, Yuchi; Cao, Yu; Zhou, Chongwu

    2014-02-07

    The effects of near-interfacial trapping induced by ionizing radiation exposure of aligned single-walled carbon nanotube (SWCNT) arrays are investigated via measurements of gate hysteresis in the transfer characteristics of aligned SWCNT field-effect transistors. Gate hysteresis is attributed to charge injection (i.e., trapping) from the SWCNTs into radiation-induced traps in regions near the SWCNT/dielectric interface. Self-consistent calculations of surface-potential, carrier density, and trapped charge are used to describe hysteresis as a function of ionizing radiation exposure. Hysteresis width (h) and its dependence on gate sweep range are investigated analytically. The effects of non-uniform trap energy distributions on the relationship between hysteresis, gate sweep range, and total ionizing dose are demonstrated with simulations and verified experimentally.

  1. Interaction between fullerene halves Cn (n ≤ 40) and single wall carbon nanotube

    NASA Astrophysics Data System (ADS)

    Sharma, Amrish; Kaur, Sandeep; Mudahar, Isha

    2016-05-01

    We have investigated the structural and electronic properties of carbon nanotube with small fullerene halves Cn (n ≤ 40) which are covalently bonded to the side wall of an armchair single wall carbon nanotube (SWCNT) using first principle method based on density functional theory. The fullerene size results in weak bonding between fullerene halves and carbon nanotube (CNT). Further, it was found that the C-C bond distance that attaches the fullerene half and CNT is of the order of 1.60 Å. The calculated binding energies indicate the stability of the complexes formed. The HOMO-LUMO gaps and electron density of state plots points towards the metallicity of the complex formed. Our calculations on charge transfer reveal that very small amount of charge is transferred from CNT to fullerene halves.

  2. Tubular Shape Fullerenes Inside Single Wall Boron Nitride Nanotubes: A Theoretical Simulation.

    PubMed

    Ma, Fengxian; Yao, Zhen; Yao, Mingguang; Liu, Ran; Cui, Tian; Liu, Bingbing

    2016-06-01

    The orientations of fullerene molecules filled in nanotubes have important influence on the electronic properties of the formed peapods and their transformations such as polymerization under certain conditions. Here we present a investigation on the preferable orientations of tubular C70, C80 and C90 fullerenes confined inside single-walled boron nitride nanotubes (SWBNNTs) by calculating the van der Waals energy between the encapsulated molecule and the hosting nanotube. The minimum entering radius and the energetically favorable radius for encapsulating C70, C80 and C90 have been determined by the reaction energy calculation. We also show that the three studied molecules filled in SWBNNTs exhibit a transition from lying (five-fold axis) orientation to tilted orientation and then to standing orientation (two-fold axis) with increasing the tube radius. The preferable orientations of the encapsulated fullerenes are irrelevant on the tube chirality, but are dependent on the radius. PMID:27427630

  3. Reptation dynamics of single-walled carbon nanotubes in a permanent network

    NASA Astrophysics Data System (ADS)

    Fakhri, Nikta; Mackintosh, Fred; Cognet, Laurent; Lounis, Brahim; Pasquali, Matteo

    2010-03-01

    Single-walled carbon nanotubes (SWCNTs) are an ideal system of semiflexible filaments with tunable bending stiffness. By exploiting their near-infrared fluorescence, we image directly the motion of SWCNTs in a network (agarose gel). We determine the SWCNT diameter (and bending stiffness) spectroscopically, and we control the network pore size by changing the agarose concentration. Image analysis shows clearly that SWCNTs move by reptation through the pore network. We quantify the dependence of SWCNTs mobility on SWCNT bending stiffness, length and pore sizes. Our results show conclusively that, even when the SWCNT length is much smaller than the persistence length, the flexibility of filaments enhances rotational diffusion. These results confirm earlier predictions of Odijk (1983), and show that the Doi-Edwards scaling fails to capture the filaments' motion. This study provides a fundamental understanding of reptation dynamics of semiflexible filaments.

  4. Hybrid Graphene and Single-Walled Carbon Nanotube Films for Enhanced Phase-Change Heat Transfer.

    PubMed

    Seo, Han; Yun, Hyung Duk; Kwon, Soon-Yong; Bang, In Cheol

    2016-02-10

    Nucleate boiling is an effective heat transfer method in power generation systems and cooling devices. In this letter, hybrid graphene/single-walled carbon nanotube (SWCNT), graphene, and SWCNT films deposited on indium tin oxide (ITO) surfaces were fabricated to investigate the enhancement of nucleate boiling phenomena described by the critical heat flux and heat transfer coefficient. The graphene films were grown on Cu foils and transferred to ITO surfaces. Furthermore, SWCNTs were deposited on the graphene layer to fabricate hybrid graphene/SWCNT films. We determined that the hybrid graphene/SWCNT film deposited on an ITO surface is the most effective heat transfer surface in pool boiling because of the interconnected network of carbon structures. PMID:26731547

  5. Selectivity of water-soluble proteins in single-walled carbon nanotube dispersions

    NASA Astrophysics Data System (ADS)

    Matsuura, Koji; Saito, Takeshi; Okazaki, Toshiya; Ohshima, Satoshi; Yumura, Motoo; Iijima, Sumio

    2006-10-01

    Proteins were screened by preparing dispersions of SWNTs to investigate the driving force of the interaction between single-walled carbon nanotubes (SWNTs) of mean diameter 1 nm and water-soluble proteins. Egg white lysozyme (LYS) and bovine serum albumin (BSA) dispersed SWNTs, whereas papain and pepsin could not. Far-UV circular dichroism spectra indicated that the LYS and BSA molecules that coat SWNT surfaces were partially denatured. From the amino acid composition, we ascribed the main driving force to the hydrophobic interactions between the side-wall of the SWNT and the inner hydrophobic domain exposed to the solvent during the three-dimensional change of the protein induced by sonication.

  6. Hierarchical morphology of carbon single-walled nanotubes during sonication in an aliphatic diamine

    SciTech Connect

    Brown, Janis M.; Anderson, David P.; Justice, Ryan S.; Lafdi, Khalid; Belfor, Max; Strong, Karla L.; Schaefer, Dale W.

    2010-07-13

    Dispersion of single-walled carbon nanotubes (SWNTs) by sonication into diamine curing agents is studied as a means to improve the dispersion of SWNTs in cured epoxy. Cured and uncured specimens are analyzed by light microscopy, electron microscopy, light scattering (LS), ultra small-angle X-ray scattering (USAXS), electrical conductivity and Raman spectroscopy. A flexible diamine (D2000) forms a stable SWNT suspension leading to good homogeneity in both the diamine and the cured epoxy. High resolution transmission electron microscopy (TEM) shows that small ropes of SWNTs (mostly under 15 nm) are present despite the sample's visual homogeneity. Further morphological investigation of cured and uncured D2000 resins using light and small-angle X-ray scattering indicates that the SWNTs are networked into fractal clusters that electrically percolate at low SWNTs loadings (0.05 wt%).

  7. Amperometric Low-Potential Detection of Malic Acid Using Single-Wall Carbon Nanotubes Based Electrodes

    PubMed Central

    Arvinte, Adina; Rotariu, Lucian; Bala, Camelia

    2008-01-01

    The electrocatalytical property of single-wall carbon nanotube (SWNT) modified electrode toward NADH detection was explored by cyclic voltammetry and amperometry techniques. The experimental results show that SWNT decrease the overvoltage required for oxidation of NADH (to +300 mV vs. Ag/AgCl) and this property make them suitable for dehydrogenases based biosensors. The behavior of the SWNT modified biosensor for L-malic acid was studied as an example for dehydrogenases biosensor. The amperometric measurements indicate that malate dehydrogenase (MDH) can be strongly adsorbed on the surface of the SWNT-modified electrode to form an approximate monolayer film. Enzyme immobilization in Nafion membrane can increase the biosensor stability. A linear calibration curve was obtained for L-malic acid concentrations between 0.2 and 1mM.

  8. Growth of metal-catalyst-free nitrogen-doped metallic single-wall carbon nanotubes.

    PubMed

    Li, Jin-Cheng; Hou, Peng-Xiang; Zhang, Lili; Liu, Chang; Cheng, Hui-Ming

    2014-10-21

    Nitrogen-doped (N-doped) single-wall carbon nanotubes (SWCNTs) were synthesized by chemical vapor deposition using SiOx nanoparticles as a catalyst and ethylenediamine as the source of both carbon and nitrogen. The N-doped SWCNTs have a mean diameter of 1.1 nm and a narrow diameter range, with 92% of them having diameters from 0.7 to 1.4 nm. Multi-wavelength laser Raman spectra and temperature-dependent electrical resistance indicate that the SWCNT sample is enriched with metallic nanotubes. These N-doped SWCNTs showed excellent electrocatalytic activity for the oxygen reduction reaction and highly selective and sensitive sensing ability for dopamine detection. PMID:25189467

  9. Magnetic-field-induced diameter-selective synthesis of single-walled carbon nanotubes.

    PubMed

    Su, Yanjie; Zhang, Yaozhong; Wei, Hao; Zhang, Liling; Zhao, Jiang; Yang, Zhi; Zhang, Yafei

    2012-03-01

    We report a facile and scalable approach to synthesize single-walled carbon nanotubes (SWNTs) with selected diameter distribution by applying a magnetic field perpendicular to the electric field in the arc plasma region. It is found that this magnetic field-induced diameter-selectivity strategy enables the control of the SWNTs with different diameter distributions in different regions, and the diameter-selective efficiency could be enhanced by modifying the direction of magnetic field. Our results indicate that the motions of the catalysts with different particle sizes, positive carbon ions and electrons are significantly influenced by the magnetic field and electromagnetic force, resulting in the different nucleation and growth processes of SWNTs due to the collective interactions between the magnetic field and arc plasma. This approach would enable a viable route towards the synthesis of SWNTs with desired diameter through the tuning of arc parameters in the arc discharge process. PMID:22301844

  10. Role of the catalyst in the growth of single-wall carbon nanotubes.

    PubMed

    Balbuena, Perla B; Zhao, Jin; Huang, Shiping; Wang, Yixuan; Sakulchaicharoen, Nataphan; Resasco, Daniel E

    2006-05-01

    Classical molecular dynamics simulations are carried out to analyze the physical state of the catalyst, and the growth of single-wall carbon nanotubes under typical temperature and pressure conditions of their experimental synthesis, emphasizing the role of the catalyst/substrate interactions. It is found that a strong cluster/substrate interaction increases the cluster melting point, modifying the initial stages of carbon dissolution and precipitation on the cluster surface. Experiments performed on model Co-Mo catalysts clearly illustrate the existence of an initial period where the catalyst is formed and no nanotube growth is observed. To quantify the nature of the Co-Mo2C interaction, quantum density functional theory is applied to characterize structural and energetic features of small Co clusters deposited on a (001) Mo2C surface, revealing a strong attachment of Co-clusters to the Mo2C surface, which may increase the melting point of the cluster and prevent cluster sintering. PMID:16792351

  11. Ultrafast nonlinear photoresponse of single-wall carbon nanotubes: a broadband degenerate investigation.

    PubMed

    Xu, Shuo; Wang, Fengqiu; Zhu, Chunhui; Meng, Yafei; Liu, Yujie; Liu, Wenqing; Tang, Jingyi; Liu, Kaihui; Hu, Guohua; Howe, Richard C T; Hasan, Tawfique; Zhang, Rong; Shi, Yi; Xu, Yongbing

    2016-04-28

    Understanding of the fundamental photoresponse of carbon nanotubes has broad implications for various photonic and optoelectronic devices. Here, Z-scan and pump-probe spectroscopy performed across 600-2400 nm were combined to give a broadband 'degenerate' mapping of the nonlinear absorption properties of single-wall carbon nanotubes (SWNTs). In contrast to the views obtained from non-degenerate techniques, sizable saturable absorption is observed from the visible to the near-infrared range, including the spectral regions between semiconducting excitonic peaks and metallic tube transitions. In addition, the broadband mapping unambiguously reveals a photobleaching to photoinduced absorption transition feature within the first semiconducting excitonic band ∼2100 nm, quantitatively marking the long-wavelength cut-off for saturable absorption of the SWNTs investigated. Our findings present a much clearer physical picture of SWNTs' nonlinear absorption characteristics, and help provide updated design guidelines for SWNT based nonlinear optical devices. PMID:27088630

  12. Polymer photovoltaic cell embedded with p-type single walled carbon nanotubes fabricated by spray process

    NASA Astrophysics Data System (ADS)

    Kim, Dal-Ho; Park, Jea-Gun

    2012-08-01

    In the current study, we fabricated polymer (poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61 butyric-acid methyl-ester (PCBM) blend) photovoltaic (PV) cells embedded with p-type single walled carbon nanotubes (SWCNTs) with tangled hair morphology. The power conversion efficiency (PCE) rapidly increased with SWCNT concentration of up to 6.83% coverage, and then decreased and saturated with increasing SWCNT concentration; i.e., the PCE peaks at 5.379%. This tendency is mainly associated with hole transport efficiency toward the transparent electrode (indium-tin-oxide (ITO)) via SWCNTs, directly determining the series resistance and shunt resistance of the polymer PV cells embedded with SWCNTs: the PV cell is increasing shunt resistance and decreasing series resistance.

  13. Exciton Radiative Lifetimes and Their Temperature Dependence in Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Miyauchi, Yuhei; Matsunaga, Ryusuke; Hirori, Hideki; Matsuda, Kazunari; Kanemitsu, Yoshihiko

    2009-03-01

    We have investigated the radiative lifetimes of excitons in single-walled carbon nanotubes (SWNTs) from simultaneous measurements of the photoluminescence (PL) lifetimes [1] and the PL quantum yields. A high-quality sample of PFO dispersed-SWNTs was used for the PL measurements. The evaluated radiative lifetimes were ˜5-15 ns for SWNTs with diameters ˜0.8-1.1 nm at room temperature. The radiative lifetimes increased with the tube diameter. The exciton spatial coherence volume (length) was of the order 10 ^2 nm along the tube axis, as deduced from the radiative lifetimes. Furthermore, we discuss the dynamics of bright and dark excitons [2] from the temperature dependence of the radiative lifetime (10 to 300 K).[3pt] [1] H. Hirori, K. Matsuda, Y. Miyauchi, S. Maruyama, and Y. Kanemitsu, Phys. Rev. Lett. 97, 257401 (2006). [0pt] [2] R. Matsunaga, K. Matsuda, and Y. Kanemitsu, Phys. Rev. Lett. 101, 147404 (2008).

  14. Near-infrared electroluminescent devices using single-wall carbon nanotubes thin flms

    NASA Astrophysics Data System (ADS)

    Kazaoui, S.; Minami, N.; Nalini, B.; Kim, Y.; Takada, N.; Hara, K.

    2005-11-01

    We have fabricated near-infrared electroluminescent (EL) devices utilizing single-wall carbon nanotubes (SWNTs) finely dispersed in a polymer, such as poly[2-methoxy-5-(2'-ethylhexyloxy]-1,4-phenylenevinylene (MEHPPV). Al/SWNT-MEHPPV/indium tin oxide thin-film devices exhibit a very promising EL response over a broad spectrum, including the range of 900-1600nm. From the analysis of the optical absorption, photoluminescence and EL spectra, as well as the current-voltage characteristics, we demonstrate that those devices exploit the intrinsic near-infrared light-emitting properties of semiconducting SWNTs and the electronic transport properties of SWNT-doped MEHPPV. Those achievements are essential for the future development of thin-film SWNT optoelectronic devices.

  15. Fabrication and performance of contamination free individual single-walled carbon nanotube optical devices.

    PubMed

    Zhou, Yuxiu; Cheng, Rong; Liu, Jianqiang; Li, Tie

    2014-06-01

    Contamination free individual single-walled carbon nanotube (SWCNT) optical devices are fabricated using a hybrid method in the purpose of increase sensitivity as well as further understanding the sensing mechanism. The devices were tested in vacuum to avoid contamination. Three typical devices are discussed comparatively. Under infrared lamp illumination, photovoltaic and photoconductive properties are revealed in device A and B respectively, while device C shows no detectable signal. The photoresponse of device B reaches 108% at 78 K, much larger than that of horizontally aligned or network carbon nanotube devices, indicating priority of the individual nanotube device structure. Interestingly, the temperature characteristics of device A and B are just the opposite. The individual SWCNT devices hold promise in high performance and low cost optical sensors as well as nano-scale solar cells. PMID:24738376

  16. Spin-orbit coupling and the static polarizability of single-wall carbon nanotubes

    SciTech Connect

    Diniz, Ginetom S. Ulloa, Sergio E.

    2014-07-14

    We calculate the static longitudinal polarizability of single-wall carbon tubes in the long wavelength limit taking into account spin-orbit effects. We use a four-orbital orthogonal tight-binding formalism to describe the electronic states and the random phase approximation to calculate the dielectric function. We study the role of both the Rashba as well as the intrinsic spin-orbit interactions on the longitudinal dielectric response, i.e., when the probing electric field is parallel to the nanotube axis. The spin-orbit interaction modifies the nanotube electronic band dispersions, which may especially result in a small gap opening in otherwise metallic tubes. The bandgap size and state features, the result of competition between Rashba and intrinsic spin-orbit interactions, result in drastic changes in the longitudinal static polarizability of the system. We discuss results for different nanotube types and the dependence on nanotube radius and spin-orbit couplings.

  17. X-ray Absorption Improvement of Single Wall Carbon Nanotube through Gadolinium Encapsulation

    NASA Astrophysics Data System (ADS)

    Alimin; Narsito, I.; Kartini; Santosa, S. J.

    2016-02-01

    X-ray absorption improvement of single-wall carbon nanotube (SWCNT) through gadolinium (Gd) encapsulation has been studied. The liquid phase adsorption using ethanol has been performed for the doping treatment. The Gd-doped SWCNT (Gd@SWCNT) was characterized by nitrogen adsorption isotherms, Raman spectroscopy, Transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA) techniques. A relatively high residual weight of Gd@SWCNT compared to non-doped SWCNT (n-SWCNT) indicated that Gd has been doped in the nanotube. Even though Gd nanoparticles could not be observed clearly by TEM image, however, a significant decrease of nitrogen uptakes at low pressure and RBM (Radial Breathing Mode) upshift of Raman spectra of Gd@SWCNT specimen suggest that the metal nanoparticles might be encapsulated in the internal tube spaces of the nanotube. It was found that Gd-doped in the SWCNT increased significantly mass attenuation coefficient of the nanotube.

  18. Controlled Growth of Semiconducting and Metallic Single-Wall Carbon Nanotubes.

    PubMed

    Liu, Chang; Cheng, Hui-Ming

    2016-06-01

    Single-wall carbon nanotubes (SWCNTs) can be either semiconducting or metallic depending on their chiral angles and diameters. The use of SWCNTs in electronics has long been hindered by the fact that the as-prepared SWCNTs are usually a mixture of semiconducting and metallic ones. Therefore, controlled synthesis of SWCNTs with a uniform electrical type or even predefined chirality has been a focus of carbon nanotube research in recent years. In this Perspective, we summarize recent progress on the controlled growth of semiconducting and metallic SWCNTs by in situ selective etching and by novel catalyst design. The advantages and mechanisms of these approaches are analyzed, and the challenges are discussed. Finally, we predict possible breakthroughs and future trends in the controlled synthesis and applications of SWCNTs. PMID:27149629

  19. Ferromagnetism/antiferromagnetism transition between semihydrogenated and fully-aminated single-wall carbon nanotubes.

    PubMed

    Deng, Qingming; Zhao, Lina; Luo, Youhua; Zhang, Meng; Jing, Long; Zhao, Yuliang

    2011-09-01

    We theoretically studied the ferromagnetism/antiferromagnetism (FM/AFM) transition between single-wall carbon nanotubes (SWCNTs) induced by chemical modifications of semihydrogenation (SH-) and full-amination (NH(2)-). We found that armchairs with large diameters of SH-CNTs (n > 3) possess FM functions with intense magnetic moments, while armchair NH(2)-CNTs (n = 4, 6, 8) are antiferromagnetic semiconductors. The FM/AFM transition is mainly dominated by different chemical modifications and sizes of SWCNTs whose distance between carbon atoms of unpaired electrons can regulate the intensity of p-p spin interactions. Moreover, the zigzag SH-CNTs and NH(2)-CNTs are NM semiconductors. Thus, the electronic and magnetic properties of the SH- or NH(2)-CNTs can be precisely modulated by controlling the hydrogenation or amination on the different types and diameters of CNTs, which provides a new and also simple process for magnetism optimization design in SWCNTs. PMID:21804988

  20. Ferromagnetism/antiferromagnetism transition between semihydrogenated and fully-aminated single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Deng, Qingming; Zhao, Lina; Luo, Youhua; Zhang, Meng; Jing, Long; Zhao, Yuliang

    2011-09-01

    We theoretically studied the ferromagnetism/antiferromagnetism (FM/AFM) transition between single-wall carbon nanotubes (SWCNTs) induced by chemical modifications of semihydrogenation (SH-) and full-amination (NH2-). We found that armchairs with large diameters of SH-CNTs (n > 3) possess FM functions with intense magnetic moments, while armchair NH2-CNTs (n = 4, 6, 8) are antiferromagnetic semiconductors. The FM/AFM transition is mainly dominated by different chemical modifications and sizes of SWCNTs whose distance between carbon atoms of unpaired electrons can regulate the intensity of p-p spin interactions. Moreover, the zigzag SH-CNTs and NH2-CNTs are NM semiconductors. Thus, the electronic and magnetic properties of the SH- or NH2-CNTs can be precisely modulated by controlling the hydrogenation or amination on the different types and diameters of CNTs, which provides a new and also simple process for magnetism optimization design in SWCNTs.

  1. Swift heavy ion induced modifications of single walled carbon nanotube thin films

    NASA Astrophysics Data System (ADS)

    Vishalli; Raina, K. K.; Avasthi, D. K.; Srivastava, Alok; Dharamvir, Keya

    2016-04-01

    Thin films of single walled carbon nanotubes (SWCNTs) were prepared by Langmuir-Blodgett method and irradiated with swift heavy ions, carbon and nickel each of energy 60 MeV. The ion beams have different electronic energy loss (Se) values and the samples were exposed to various irradiation doses. The irradiated films were characterized using Raman and optical absorption spectroscopy. Raman spectroscopy results indicate the competing processes of defect creation and healing (annealing) of SWCNTs at lower fluences, while at higher fluences defect creation or damage dominates. In UV-Vis-NIR spectroscopy we find that there is decrease in the intensity of characteristic peaks with every increasing fluence, indicating decrease in the optically active states with irradiation.

  2. Dispersion of Single Walled Carbon Nanotubes Using a Novel Type of Sonication: Focused Sonication.

    PubMed

    Sachin, Bramhe N; Ae, Hwangbo Seon; Chu, Min Cheol

    2016-03-01

    We demonstrate the use of novel type of sonication method, focused sonication, with added advantages over bath and probe type of sonication for the dispersion of single walled carbon nanotubes (SWNT). Di-chloro benzene was used as the solvent for dispersion of SWNT. Results from focused sonication and bath sonication were compared and found that focused sonication results in better dispersion. Also Raman spectroscopy was analysed to ascertain if focused sonication causes any damage to the tubes and it was found that there was no damage to the SWNT. We believe that with the added advantages like in-situ temperature control and large sample volume processing, focused sonication would prove to be the most proficient method of sonication for dispersion of nanoparticles. PMID:27455717

  3. Single-walled carbon nanotubes functionalized by a series of dichlorocarbenes: DFT study

    NASA Astrophysics Data System (ADS)

    Petrushenko, Igor K.; Petrushenko, Konstantin B.

    2016-02-01

    The structural and elastic properties of neutral and ionized dichlorocarbene (CCl2) functionalized single-walled carbon nanotubes (SWCNTs) were studied using density functional theory (DFT). The Young’s modulus of ionized pristine SWCNTs is found to decrease in comparison to that of neutral models. The interesting effect of increase in Young’s modulus values of ionized functionalized SWCNTs is observed. We ascribe this feature to the concurrent processes of the bond elongation on ionization and the local deformation on cycloaddition. The strong dependence of the elasticity modulus on the number of addends is also observed. However, the CCl2-attached SWCNTs in their neutral and ionized forms remain strong enough to be suitable for the reinforcement of composites. In contrast to the elastic properties, the binding energies do not change significantly, irrespective of CCl2 coverage.

  4. Extinction properties of single-walled carbon nanotubes: Two-fluid model

    SciTech Connect

    Moradi, Afshin

    2014-03-15

    The extinction spectra of a single-walled carbon nanotube are investigated, within the framework of the vector wave function method in conjunction with the hydrodynamic model. Both polarizations of the incident plane wave (TE and TM with respect to the x-z plane) are treated. Electronic excitations on the nanotube surface are modeled by an infinitesimally thin layer of a two-dimensional electron gas represented by two interacting fluids, which takes into account the different nature of the σ and π electrons. Numerical results show that strong interaction between the fluids gives rise to the splitting of the extinction spectra into two peaks in quantitative agreement with the π and σ + π plasmon energies.

  5. 13 nm Exciton Size in (6,5) Single-Wall Carbon Nanotubes.

    PubMed

    Mann, Christoph; Hertel, Tobias

    2016-06-16

    Electron-hole correlation lengths, also termed exciton size, for (6,5) single-wall carbon nanotubes (SWNTs) are determined using femtosecond time-resolved pump-probe spectroscopy. The phase space filling model is used to obtain the sizes of the first subband exciton in samples of isolated and of bundled SWNTs. The experiments indicate that the exciton size of (13 ± 3) nm is a factor of 6 higher than previous experimental estimates and theoretical predictions for vacuum suspended SWNTs. This surprising result may be attributed at least in part to the effect of the dielectric environment on exciton sizes and supports recent theoretical findings predicting that screening in SWNTs may enhance rather than reduce electron-hole interactions for separations larger than the tube diameter. Thereby, the work also points to the unique nature of screening and electronic correlations in one-dimensional semiconductors. PMID:27249311

  6. Structural and electronic properties of chiral single-wall copper nanotubes

    NASA Astrophysics Data System (ADS)

    Duan, YingNi; Zhang, JianMin; Xu, KeWei

    2014-04-01

    The structural, energetic and electronic properties of chiral ( n, m) (3⩽ n⩽6, n/2⩽ m⩽ n) single-wall copper nanotubes (CuNTs) have been investigated by using projector-augmented wave method based on density-functional theory. The (4, 3) CuNT is energetically stable and should be observed experimentally in both free-standing and tip-suspended conditions, whereas the (5, 5) and (6, 4) CuNTs should be observed in free-standing and tip-suspended conditions, respectively. The number of conductance channels in the CuNTs does not always correspond to the number of atomic strands comprising the nanotube. Charge density contours show that there is an enhanced interatomic interaction in CuNTs compared with Cu bulk. Current transporting states display different periods and chirality, the combined effects of which lead to weaker chiral currents on CuNTs.

  7. Predicting excitonic gaps of semiconducting single-walled carbon nanotubes from a field theoretic analysis

    SciTech Connect

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-17

    We demonstrate that a non-perturbative framework for the treatment of the excitations of single walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. As a result, we test this theory explicitly on the data reported in [NanoLetters 5, 2314 (2005)] and [Phys. Rev. B 82, 195424 (2010)] and so demonstrate the method works over a wide range of reported excitonic spectra.

  8. Indium Oxide-Single-Walled Carbon Nanotube Composite for Ethanol Sensing at Room Temperature.

    PubMed

    Ellis, James E; Green, Uri; Sorescu, Dan C; Zhao, Yong; Star, Alexander

    2015-02-19

    Utilizing a sol-gel synthesis, indium oxide is grown on the surface of oxidized single-walled carbon nanotubes (SWCNT) to form a hybrid material with high conductivity and sensitivity toward certain organic vapors. The room-temperature sensing of dilute ethanol and acetone vapors on the surface of indium oxide/SWCNT hybrid material is studied using electrical conductance experiments in a nonoxidizing environment. Through testing of variously calcinated materials, it was observed that the degree of annealing greatly affects the material's response to acetone and ethanol, such that the intermediate calcination condition yields the best sensitivity. DFT simulations are used to study the interface between defective SWCNT and indium oxide, as well as the interaction between ethanol and acetone molecules with the indium oxide/SWCNT hybrid material. PMID:26262491

  9. Selective adsorption of proteins on single-wall carbon nanotubes by using a protective surfactant.

    PubMed

    Knyazev, Anton; Louise, Loïc; Veber, Michèle; Langevin, Dominique; Filoramo, Arianna; Prina-Mello, Adriele; Campidelli, Stéphane

    2011-12-16

    The dispersion of highly hydrophobic carbon materials such as carbon nanotubes in biological media is a challenging issue. Indeed, the nonspecific adsorption of proteins occurs readily when the nanotubes are introduced in biological media; therefore, a methodology to control adsorption is in high demand. To address this issue, we developed a bifunctional linker derived from pyrene that selectively enables or prevents the adsorption of proteins on single-wall carbon nanotubes (SWNTs). We demonstrated that it is possible to decrease or completely suppress the adsorption of proteins on the nanotube sidewall by using proper functionalization (either covalent or noncovalent). By subsequently activating the functional groups on the nanotube derivatives, protein adsorption can be recovered and, therefore, controlled. Our approach is simple, straightforward, and potentially suitable for other biomolecules that contain thio or amino groups available for coupling. PMID:22095560

  10. Multiple helical configuration and quantity threshold of graphene nanoribbons inside a single-walled carbon nanotube

    PubMed Central

    Li, Yifan; Chen, Wei; Ren, Hongru; Zhou, Xuyan; Li, Hui

    2015-01-01

    Molecular dynamics simulation has been carried out to explore the configuration and quantity threshold of multiple graphene nanoribbons (GNRs) in single-walled carbon nanotube (SWCNT). The simulation results showed that several GNRs tangled together to form a perfect spiral structure to maximize the π-π stacking area when filling inside SWCNT. The formation of multiple helical configuration is influenced by the combined effect of structure stability, initial arrangement and tube space, meanwhile its forming time is related to helical angle. The simulated threshold of GNRs in SWCNT decreases with GNR width but increases with SWCNT diameter, and two formulas have come up in this study to estimate the quantity threshold for GNRs. It has been found that multilayered graphite is hard to be stripped in SWCNT because the special helical configuration with incompletely separated GNRs is metastable. This work provides a possibility to control the configuration of GNR@SWCNT. PMID:26374276

  11. Suspended single-walled carbon-nanotube field-effect transistor for gas sensing application

    NASA Astrophysics Data System (ADS)

    Wada, Yukiko; Fujita, Yoshihiro; Takei, Kuniharu; Arie, Takayuki; Akita, Seiji

    2015-06-01

    We investigate the pressure dependence of transfer characteristics of suspended single-walled carbon-nanotube field-effect transistors. We find that the gate bias around the charge neutral point with low drain current is appropriate for gas sensing application, while the high gate bias condition with high drain current that induces Joule heating in the suspended region for the desorption of the adsorbed molecules is preferable for the vacuum gauge application based on the heat exchange surrounding gas molecules, where the temperature at the suspended channel is investigated based on the simple one-dimensional heat transport model. We also revealed that the pressure dependence of the channel conductance at the gate bias around the charge neutral point can be explained by the Langmuir isotherm.

  12. Chemisorption and Diffusion of H on a Graphene Sheet and Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Dzegilenko, Fedor; Menon, Madhu

    2000-01-01

    Recent experiments on hydrogen storage in single wall nanotubes and nanotube bundles have reported large fractional weight of stored molecular hydrogen which are not in agreement with theoretical estimates based of simulation of hydrogen storage by physisorption mechanisms. Hydrogen storage in catalytically doped nanotube bundles indicate that atomic H might undergo chemisorption changing the basic nature of the storage mechanism under investigation by many groups. Using a generalized tight-binding molecular dynamics (GTBMD) method for reactive C-H dynamics, we investigate chemisorption and diffusion of atomic H on graphene sheet and C nanotubes. Effective potential energy surfaces (EPS) for chemisorption and diffusion are calculated for graphene sheet and nanotubes of different curvatures. Analysis of the activation barriers and quantum rate constants, computed via wave-packet dynamics method, will be discussed in this presentation.

  13. Torsional characteristics of graphene nanoribbons encapsulated in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Fang, Te-Hua; Chang, Win-Jin; Feng, Yu-Lun; Lu, Deng-Maw

    2016-09-01

    Molecular dynamics (MD) simulations were performed to study the torsional characteristics of a graphene nanoribbon encapsulated in a single-walled carbon nanotube (GNR@SWCNT) with different chiralities at different temperatures. Based on the simulations, the relationship between the shear stress and the twist angle was obtained. The maximum shear stress increases with an increase in chirality. However, the corresponding twist angle decreases with increasing chirality. GNR@SWCNT withstands a smaller twist angle compared with a single SWCNT. In addition, the interaction force between the GNR and the SWCNT increases with increasing temperature. GNR@SWCNT at an elevated temperature is easier to break during torsion with a lower twist angle. The results are valuable for the design of nanocomposites composed of carbon nanotubes and graphene materials.

  14. Single-walled carbon nanotube networks for flexible and printed electronics

    NASA Astrophysics Data System (ADS)

    Zaumseil, Jana

    2015-07-01

    Networks of single-walled carbon nanotubes (SWNTs) can be processed from solution and have excellent mechanical properties. They are highly flexible and stretchable. Depending on the type of nanotubes (semiconducting or metallic) they can be used as replacements for metal or transparent conductive oxide electrodes or as semiconducting layers for field-effect transistors (FETs) with high carrier mobilities. They are thus competitive alternatives to other solution-processable materials for flexible and printed electronics. This review introduces the basic properties of SWNTs, current methods for dispersion and separation of metallic and semiconducting SWNTs and techniques to deposit and pattern dense networks from dispersion. Recent examples of applications of carbon nanotubes as conductors and semiconductors in (opto-)electronic devices and integrated circuits will be discussed.

  15. Separation of surfactant functionalized single-walled carbon nanotubes via free solution electrophoresis method

    NASA Astrophysics Data System (ADS)

    Scheibe, Blazej; Rümmeli, Mark H.; Borowiak-Palen, Ewa; Kalenczuk, Ryszard J.

    2011-04-01

    This work presents the application of the free solution electrophoresis method (FSE) in the metallic / semiconductive (M/S) separation process of the surfactant functionalized single-walled carbon nanotubes (SWCNTs). The SWCNTs synthesized via laser ablation were purified through high vacuum annealing and subsequent refluxing processes in aqua regia solution. The purified and annealed material was divided into six batches. First three batches were dispersed in anionic surfactants: sodium dodecyl sulfate (SDS), sodium cholate (SC) and sodium deoxycholate (DOC). The next three batches were dispersed in cationic surfactants: cetrimonium bromide (CTAB), benzalkonium chloride (BKC) and cetylpyridinium chloride (CPC). All the prepared SWCNTs samples were subjected to FSE separation process. The fractionated samples were recovered from control and electrode areas and annealed in order to remove the adsorbed surfactants on carbon nanotubes (CNTs) surface. The changes of the van Hove singularities (vHS) present in SWCNTs spectra were investigated via UV-Vis-NIR optical absorption spectroscopy (OAS).

  16. All-printed and transparent single walled carbon nanotube thin film transistor devices

    NASA Astrophysics Data System (ADS)

    Sajed, Farzam; Rutherglen, Christopher

    2013-09-01

    We present fully transparent single-walled all-carbon nanotube thin film transistors (SWCNT TFT) fabricated using low-cost inkjet printing methods. Such a demonstration provides a platform towards low cost fully printed transparent electronics. The SWCNT TFTs were printed with metallic and semiconducting SWCNT using a room temperature printing process, without the requirement of expensive cleanroom facilities. The unoptimized SWCNT TFTs fabricated exhibited an Ion/off ratio of 92 and mobility of 2.27 cm2V-1s-1 and transmissivity of 82%. The combination of both high electrical performance and high transparency make all-SWCNT TFTs desirable for next generation transparent display backplanes and products such as Google Glass.

  17. Chirality dependent elastic properties of single-walled boron nitride nanotubes under uniaxial and torsional loading

    SciTech Connect

    Anoop Krishnan, N. M. Ghosh, Debraj

    2014-02-14

    The elastic behavior of single-walled boron nitride nanotubes is studied under axial and torsional loading. Molecular dynamics simulation is carried out with a tersoff potential for modeling the interatomic interactions. Different chiral configurations with similar diameter are considered to study the effect of chirality on the elastic and shear moduli. Furthermore, the effects of tube length on elastic modulus are also studied by considering different aspects ratios. It is observed that both elastic and shear moduli depend upon the chirality of a nanotube. For aspect ratios less than 15, the elastic modulus reduces monotonically with an increase in the chiral angle. For chiral nanotubes, the torsional response shows a dependence on the direction of loading. The difference between the shear moduli against and along the chiral twist directions is maximum for chiral angle of 15°, and zero for zigzag (0°) and armchair (30°) configurations.

  18. 3D Viability Imaging of Tumor Phantoms Treated with Single Walled Carbon Nanohorns and Photothermal Therapy

    PubMed Central

    Whitney, Jon; Dewitt, Matthew; Whited, Bryce M.; Carswell, William; Simon, Alex; Rylander, Christopher G.; Rylander, Marissa Nichole

    2013-01-01

    Objective A new image analysis method called the Spatial Phantom Evaluation of Cellular Thermal Response in Layers (SPECTRL) is presented for assessing spatial viability response to nanoparticle enhanced photothermal therapy in tissue representative phantoms. Materials and Methods Sodium alginate phantoms seeded with MDA-MB-231 breast cancer cells and single walled nanohorns were laser irradiated with an ytterbium fiber laser at a wavelength of 1064 nm and irradiance of 3.8 watts/cm2 for 10–80 seconds. SPECTRL quantitatively assessed and correlated 3D viability with spatiotemporal temperature. Results and Conclusions Based on this analysis, kill and transition zones increased from 3.7 mm3 and 13 mm3 respectively to 44.5 mm3 and 44.3 mm3 as duration was increased from 10–80 seconds. SPECTRL provides a quantitative tool for measuring precise spatial treatment regions, providing information necessary to tailor therapy protocols. PMID:23780336

  19. The effect of fibronectin on structural and biological properties of single walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Atyabi, Fatemeh; Omidvar, Ramin; Shokrgozar, Mohammad Ali; Sadeghizadeh, Majid

    2015-06-01

    Despite the attractive properties of carbon nanotubes (CNTs), cytoxicity and hydrophobicity are two main considerable features which limit their application in biomedical fields. It was well established that treating CNTs with extracellular matrix components could reduce these unfavourable characteristics. In an attempt to address these issues, fibronectin (FN) with different concentrations was loaded on single walled carbon nanotubes (SWCNTs) substrate. Scanning electron microscope, atomic force microscopy (AFM), contact angles and X-ray photoelectron spectroscopy (XPS) were preformed in order to characterize FN loaded SWCNTs substrates. According to XPS and AFM results, FN could interact with SWCNTs and for this, the hydrophilicity of SWCNTs was improved. Additionally, SWCNT modified with FN showed less cytotoxicity compared with neat SWCNT. Finally, FN was shown to act as an interesting extracellular component for enhancing the biological properties of SWCNT.

  20. Universal Response of Single-Wall Carbon Nanotubes to Radial Compression

    NASA Astrophysics Data System (ADS)

    Barboza, A. P. M.; Chacham, H.; Neves, B. R. A.

    2009-01-01

    The mechanical response of single-wall carbon nanotubes to radial compression is investigated via atomic force microscopy (AFM). We find that the force F applied by an AFM tip (with radius R) onto a nanotube (with diameter d), rescaled through the quantity Fd3/2(2R)-1/2, falls into a universal curve as a function of the compressive strain. Such universality is reproduced analytically in a model where the graphene bending modulus is the only fitting parameter. The application of this model to the radial Young’s modulus Er leads to a further universal-type behavior which explains the large variations of nanotube Er reported in the literature.

  1. Coupling between flexural modes in free vibration of single-walled carbon nanotubes

    SciTech Connect

    Liu, Rumeng; Wang, Lifeng

    2015-12-15

    The nonlinear thermal vibration behavior of a single-walled carbon nanotube (SWCNT) is investigated by molecular dynamics simulation and a nonlinear, nonplanar beam model. Whirling motion with energy transfer between flexural motions is found in the free vibration of the SWCNT excited by the thermal motion of atoms where the geometric nonlinearity is significant. A nonlinear, nonplanar beam model considering the coupling in two vertical vibrational directions is presented to explain the whirling motion of the SWCNT. Energy in different vibrational modes is not equal even over a time scale of tens of nanoseconds, which is much larger than the period of fundamental natural vibration of the SWCNT at equilibrium state. The energy of different modes becomes equal when the time scale increases to the microsecond range.

  2. Recent Progress in Obtaining Semiconducting Single-Walled Carbon Nanotubes for Transistor Applications.

    PubMed

    Islam, Ahmad E; Rogers, John A; Alam, Muhammad A

    2015-12-22

    High purity semiconducting single-walled carbon nanotubes (s-SWCNTs) with a narrow diameter distribution are required for high-performance transistors. Achieving this goal is extremely challenging because the as-grown material contains mixtures of s-SWCNTs and metallic- (m-) SWCNTs with wide diameter distributions, typically inadequate for integrated circuits. Since 2000, numerous ex situ methods have been proposed to improve the purity of the s-SWCNTs. The majority of these techniques fail to maintain the quality and integrity of the s-SWCNTs with a few notable exceptions. Here, the progress in realizing high purity s-SWCNTs in as-grown and post-processed materials is highlighted. A comparison of transistor parameters (such as on/off ratio and field-effect mobility) obtained from test structures establishes the effectiveness of various methods and suggests opportunities for future improvements. PMID:26540144

  3. Heteroepitaxial Growth of Single-Walled Carbon Nanotubes from Boron Nitride

    PubMed Central

    Tang, Dai-Ming; Zhang, Li-Li; Liu, Chang; Yin, Li-Chang; Hou, Peng-Xiang; Jiang, Hua; Zhu, Zhen; Li, Feng; Liu, Bilu; Kauppinen, Esko I.; Cheng, Hui-Ming

    2012-01-01

    The growth of single-walled carbon nanotubes (SWCNTs) with predefined structure is of great importance for both fundamental research and their practical applications. Traditionally, SWCNTs are grown from a metal catalyst with a vapor-liquid-solid mechanism, where the catalyst is in liquid state with fluctuating structures, and it is intrinsically unfavorable for the structure control of SWCNTs. Here we report the heteroepitaxial growth of SWCNTs from a platelet boron nitride nanofiber (BNNF), which is composed of stacked (002) planes and is stable at high temperatures. SWCNTs are found to grow epitaxially from the open (002) edges of the BNNFs, and the diameters of the SWCNTs are multiples of the BN (002) interplanar distance. In situ transmission electron microscopy observations coupled with first principles calculations reveal that the growth of SWCNTs from the BNNFs follows a vapor-solid-solid mechanism. Our work opens opportunities for the control over the structure of SWCNTs by hetero-crystallographic epitaxy. PMID:23240076

  4. Magnetic Property Measurements on Single Wall Carbon Nanotube-Polyimide Composites

    NASA Technical Reports Server (NTRS)

    Sun, Keun J.; Wincheski, Russell A.; Park, Cheol

    2008-01-01

    Temperature and magnetic field dependent magnetization measurements were performed on polyimide nanocomposite samples, synthesized with various weight percentages of single wall carbon nanotubes. It was found that the magnetization of the composite, normalized to the mass of nanotube material in the sample, decreased with increasing weight percentage of nanotubes. It is possible that the interfacial coupling between the carbon nanotube (CNT) fillers and the polyimide matrix promotes the diamagnetic response from CNTs and reduces the total magnetization of the composite. The coercivity of the samples, believed to originate from the residual magnetic catalyst particles, was enhanced and had a stronger temperature dependence as a result of the composite synthesis. These changes in magnetic properties can form the basis of a new approach to investigate the interfacial properties in the CNT nanocomposites through magnetic property measurements.

  5. The structure and electronic properties of copper iodide 1D nanocrystals within single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kiselev, N. A.; Kumskov, A. S.; Zhigalina, V. G.; Verbitskiy, N. I.; Yashina, L. V.; Chuvilin, A. L.; Vasiliev, A. L.; Eliseev, A. A.

    2013-11-01

    Copper iodide one-dimensional nanocrystals within single walled carbon nanotubes (1D CuI@SWCNTs), i.e. meta-nanotubes [1], were investigated by high resolution electron microscopy (HRTEM). In meta-nanotubes of diameter Dm = 1.3-1.4 nm produced by arc-discharge (AD) method close-packed hexagonal or deformed cubic 1D crystal anion sublattices were observed with cations in octahedral or tetrahedral positions. These two sublattices reversibly transform to one another. In catalysed chemical vapour deposition (CCVD) meta-nanotubes of diameters Dm = 1.5-2.0 nm cubic anion sublattices are formed. For diameters >=2.0 nm three-dimensional (3D) crystallization is observed.

  6. Preparation of cluster states with endohedral fullerenes in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hu, Y. M.; Chen, C. Y.; Yang, W. L.; Feng, M.

    2012-05-01

    We propose two scalable methods for generation of cluster states with arrays of endohedral fullerenes 15N@C60 residing in single-walled carbon nanotubes (SWCNTs) using direct and indirect methods, respectively. The direct method makes use of a series of controlled-phase flip (CPF) gates by electron spin resonance pulses of selective frequencies and durations, where the CPF gates are realized by magnetic-dipole couplings between the electron spins of the nearest-neighbour fullerenes in SWCNTs. The indirect method resorts to auxiliary mobile electron as the flying qubit, which transfers quantum information from one site to another. This greatly releases the requirements for the distance between fullerenes in SWCNTs. The decoherence effect and experimental feasibility are also discussed based on currently available technology.

  7. Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field

    PubMed Central

    García-García, Amanda; Vergaz, Ricardo; Algorri, José F; Zito, Gianluigi; Cacace, Teresa; Marino, Antigone; Otón, José M

    2016-01-01

    Summary Single-wall carbon nanotubes (SWCNT) are anisotropic nanoparticles that can cause modifications in the electrical and electro-optical properties of liquid crystals. The control of the SWCNT concentration, distribution and reorientation in such self-organized fluids allows for the possibility of tuning the liquid crystal properties. The alignment and reorientation of CNTs are studied in a system where the liquid crystal orientation effect has been isolated. Complementary studies including Raman spectroscopy, microscopic inspection and impedance studies were carried out. The results reveal an ordered reorientation of the CNTs induced by an electric field, which does not alter the orientation of the liquid crystal molecules. Moreover, impedance spectroscopy suggests a nonnegligible anchoring force between the CNTs and the liquid crystal molecules. PMID:27547599

  8. Sensing Reversible Protein–Ligand Interactions with Single-Walled Carbon Nanotube Field-Effect Transistors

    PubMed Central

    2015-01-01

    We report on the reversible detection of CaptAvidin, a tyrosine modified avidin, with single-walled carbon nanotube (SWNT) field-effect transistors (FETs) noncovalently functionalized with biotin moieties using 1-pyrenebutyric acid as a linker. Binding affinities at different pH values were quantified, and the sensor’s response at various ionic strengths was analyzed. Furthermore, protein “fingerprints” of NeutrAvidin and streptavidin were obtained by monitoring their adsorption at several pH values. Moreover, gold nanoparticle decorated SWNT FETs were functionalized with biotin using 1-pyrenebutyric acid as a linker for the CNT surface and (±)-α-lipoic acid linkers for the gold surface, and reversible CaptAvidin binding is shown, paving the way for potential dual mode measurements with the addition of surface enhanced Raman spectroscopy (SERS). PMID:25126155

  9. Optical and thermal response of single-walled carbon nanotube-copper sulfide nanoparticle hybrid nanomaterials.

    PubMed

    Tseng, Yi-Hsuan; He, Yuan; Lakshmanan, Santana; Yang, Chang; Chen, Wei; Que, Long

    2012-11-16

    This paper reports the optical and thermal response of a single-walled carbon nanotube-copper sulfide nanoparticle (SWNT-CuS NP) hybrid nanomaterial and its application as a thermoelectric generator. The hybrid nanomaterial was synthesized using oleylamine molecules as the linker molecules between SWNTs and CuS NPs. Measurements found that the hybrid nanomaterial has significantly increased light absorption (up to 80%) compared to the pure SWNT. Measurements also found that the hybrid nanomaterial thin-film devices exhibit a clear optical and thermal switching effect, which can be further enhanced up to 10 ×  by asymmetric illumination of light and thermal radiation on the thin-film devices instead of symmetric illumination. A simple prototype thermoelectric generator enabled by the hybrid nanomaterials is demonstrated, indicating a new route for achieving thermoelectricity. PMID:23089651

  10. Adhesion energy of single wall carbon nanotube loops on various substrates

    SciTech Connect

    Li, Tianjun; Ayari, Anthony; Bellon, Ludovic

    2015-04-28

    The physics of adhesion of one-dimensional nano structures such as nanotubes, nano wires, and biopolymers on different substrates is of great interest for the study of biological adhesion and the development of nano electronics and nano mechanics. In this paper, we present force spectroscopy experiments of individual single wall carbon nanotube loops using a home-made interferometric atomic force microscope. Characteristic force plateaus during the peeling process allow the quantitative measurement of the adhesion energy per unit length on various substrates: graphite, mica, platinum, gold, and silicon. Moreover, using a time-frequency analysis of the deflection of the cantilever, we estimate the dynamic stiffness of the contact, providing more information on the nanotube configurations and its intrinsic mechanical properties.

  11. Interaction of [FeFe]-hydrogenases with single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Svedruzic Chang, Drazenka; McDonald, Timothy J.; Kim, Yong-Hyun; Blackburn, Jeffrey L.; Heben, Michael J.; King, Paul W.

    2007-09-01

    Single-walled carbon nanotubes (SWNT) are promising candidates for use in energy conversion devices as an active photo-collecting elements, for dissociation of bound excitons and charge-transfer from photo-excited chromophores, or as molecular wires to transport charge. Hydrogenases are enzymes that efficiently catalyze the reduction of protons from a variety of electron donors to produce molecular hydrogen. Hydrogenases together with SWNT suggest a novel biohybrid material for direct conversion of sunlight into H II. Here, we report changes in SWNT optical properties upon addition of recombinant [FeFe] hydrogenases from Clostridium acetobutylicum and Chlamydomonas reinhardtii. We find evidence that novel and stable charge-transfer complexes are formed under conditions of the hydrogenase catalytic turnover, providing spectroscopic handles for further study and application of this hybrid system.

  12. Heat welding of non-orthogonal X-junction of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yang, Xueming; Han, Zhonghe; Li, Yonghua; Chen, Dongci; Zhang, Pu; To, Albert C.

    2012-09-01

    Though X-junctions of single-walled carbon nanotubes (SWCNTs) have been intensively studied, studies concerning non-orthogonal X-junctions are still very rare. In this paper, the heat welding of defect-free non-orthogonal X-junctions with different crossed angles are investigated by molecular dynamics simulations. The difference between the heat welding of non-orthogonal and orthogonal X-junctions is described, and the angle effect on the configuration and stability of the heat welded non-orthogonal X-junctions is discussed. Compared with the orthogonal X-junction, two crossed SWCNTs with a smaller non-orthogonal angle are easier to join by heat welding, and this may be an important reason why the large tubes are difficult to join, whereas large nanotube bundles are easier to observe in experiments.

  13. CVD-grown horizontally aligned single-walled carbon nanotubes: synthesis routes and growth mechanisms.

    PubMed

    Ibrahim, Imad; Bachmatiuk, Alicja; Warner, Jamie H; Büchner, Bernd; Cuniberti, Gianaurelio; Rümmeli, Mark H

    2012-07-01

    Single-walled carbon nanotubes (SWCNTs) have attractive electrical and physical properties, which make them very promising for use in various applications. For some applications however, in particular those involving electronics, SWCNTs need to be synthesized with a high degree of control with respect to yield, length, alignment, diameter, and chirality. With this in mind, a great deal of effort is being directed to the precision control of vertically and horizontally aligned nanotubes. In this review the focus is on the latter, horizontally aligned tubes grown by chemical vapor deposition (CVD). The reader is provided with an in-depth review of the established vapor deposition orientation techniques. Detailed discussions on the characterization routes, growth parameters, and growth mechanisms are also provided. PMID:22619167

  14. Theoretical analysis on nonlinear vibration of fluid flow in single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Valipour, P.; Ghasemi, S. E.; Khosravani, Mohammad Reza; Ganji, D. D.

    2016-04-01

    In this study, the concept of nonlocal continuum theory is used to characterize the nonlinear vibration of an embedded single-walled carbon nanotube. The Pasternak-type model is employed to simulate the interaction of the SWNTs. The parameterized perturbation method is used to solve the corresponding nonlinear differential equation. The effects of the vibration amplitude, flow velocity, nonlocal parameter, and stiffness of the medium on the nonlinear frequency variation are presented. The result shows that by increasing the Winkler constant, the nonlinear frequency decreases, especially for low vibration amplitudes. In addition, it is resulted that influence of the nonlocal parameter is greater at higher flow velocities in comparison with lower flow velocities.

  15. Polymers encapsulated in short single wall carbon nanotubes: pseudo-1D morphologies and induced chirality.

    PubMed

    Kumar, Sunil; Pattanayek, Sudip K; Pereira, Gerald G

    2015-03-21

    Molecular dynamics simulations are performed to investigate the stable morphologies of semi-flexible polymer chains within a single wall carbon nanotube (CNT). We characterize these morphologies with a variety of measures. Due to the different curvature inside the CNT to outside, there are increased numbers of polymer-CNT bead contacts for polymers which reside inside the CNT. A sufficiently long polymer chain first adsorbs on the exterior of the nanotube and subsequently moves inside the cavity of the nanotube. At equilibrium, the polymer configuration consists of a central stem surrounded by helically wrapped layers. Sections of the polymer outside the CNT have helical conformations (for CNTs of small radius) or circular arrangements (for CNTs of larger radius). Polymers encapsulated within the CNT have an increased chirality due to packing of the beads and this chirality is further enhanced for moderately stiff chains. PMID:25796260

  16. Multiple helical configuration and quantity threshold of graphene nanoribbons inside a single-walled carbon nanotube.

    PubMed

    Li, Yifan; Chen, Wei; Ren, Hongru; Zhou, Xuyan; Li, Hui

    2015-01-01

    Molecular dynamics simulation has been carried out to explore the configuration and quantity threshold of multiple graphene nanoribbons (GNRs) in single-walled carbon nanotube (SWCNT). The simulation results showed that several GNRs tangled together to form a perfect spiral structure to maximize the π-π stacking area when filling inside SWCNT. The formation of multiple helical configuration is influenced by the combined effect of structure stability, initial arrangement and tube space, meanwhile its forming time is related to helical angle. The simulated threshold of GNRs in SWCNT decreases with GNR width but increases with SWCNT diameter, and two formulas have come up in this study to estimate the quantity threshold for GNRs. It has been found that multilayered graphite is hard to be stripped in SWCNT because the special helical configuration with incompletely separated GNRs is metastable. This work provides a possibility to control the configuration of GNR@SWCNT. PMID:26374276

  17. DNA Linked To Single Wall Carbon Nanotubes: Covalent Versus Non-Covalent Approach

    NASA Astrophysics Data System (ADS)

    Chung, C.-L.; Nguyen, K.; Lyonnais, S.; Streiff, S.; Campidelli, S.; Goux-Capes, L.; Bourgoin, J.-P.; Filoramo, A.

    2008-10-01

    Nanometer-scale structures represent a novel and intriguing field, where scientists and engineers manipulate materials at the atomic and molecular scale levels to produce innovative materials. Carbon nanotubes constitute a relatively new class of materials exhibiting exceptional mechanical and electronic properties and were found to be promising candidates for molecular electronics, sensing or biomedical applications. Considering the bottom-up strategy in nanotechnology, the combination of the recognition properties of DNA with the electronic properties of single walled carbon nanotubes (SWNTs) seems to be a promising approach for the future of electronics. With the aim to assemble DNA with SWNTs, two complementary strategies have been envisioned: the covalent linkage of DNA on carboxylic groups of SWNTs under classical coupling condition and the non-covalent approach based on biotin-streptavidin molecular recognition properties. Here, we present and compare the results that we obtained with these two different methods; we want to objectively show the advantages and disadvantages of each approach.

  18. Sample preparation protocols for realization of reproducible characterization of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Decker, J. E.; Hight Walker, A. R.; Bosnick, K.; Clifford, C. A.; Dai, L.; Fagan, J.; Hooker, S.; Jakubek, Z. J.; Kingston, C.; Makar, J.; Mansfield, E.; Postek, M. T.; Simard, B.; Sturgeon, R.; Wise, S.; Vladar, A. E.; Yang, L.; Zeisler, R.

    2009-12-01

    Harmonized sample pre-treatment is an essential first step in ensuring quality of measurements as regards repeatability, interlaboratory reproducibility and commutability. The development of standard preparation methods for single-wall carbon nanotube (SWCNT) samples is therefore essential to progress in their investigation and eventual commercialization. Here, descriptions of sample preparation and pre-treatment for the physicochemical characterization of SWCNTs are provided. Analytical methods of these protocols include scanning electron microscopy (dry, wet), transmission electron microscopy (dry, wet), atomic force microscopy, inductively coupled plasma mass spectrometry, neutron activation analysis, Raman spectroscopy (dry, wet), UV-Vis-NIR absorption and photoluminescence spectroscopy, manometric isothermal gas adsorption and thermogravimetric analysis. Although sample preparation refers to these specific methods, application to other methods for measurement and characterization of SWCNTs can be envisioned.

  19. Dynamics of individual single-walled carbon nanotubes in water by real-time visualization.

    PubMed

    Duggal, Rajat; Pasquali, Matteo

    2006-06-23

    Individual single-walled carbon nanotubes (SWNTs) in aqueous suspension are visualized directly by fluorescence video microscopy. The fluorescent tagging is simple, biocompatible, and does not modify the SWNTs. The dynamics of individual SWNTs in water are observed and quantified for the first time. We measure the confined rotational diffusion coefficient and find it in reasonable agreement with predictions based on confined diffusion of dilute Brownian rods. We determine the critical concentration at which SWNTs in suspensions start interacting. By analyzing the fluctuating shape of SWNTs in the 3 to 5 microm range, we determine that their persistence length ranges between 32 and 174 microm, in agreement with theoretical estimates; thus, commonly available SWNTs in liquids can be considered as rigid Brownian rods in the absence of imposed external fields or self-attractive forces. PMID:16907258

  20. Dispersion of single-walled carbon nanotubes modified with poly-l-tyrosine in water.

    PubMed

    Kojima, Mio; Chiba, Tomoka; Niishima, Junichiro; Higashi, Toshiaki; Fukuda, Takahiro; Nakajima, Yoshikata; Kurosu, Shunji; Hanajiri, Tatsuro; Ishii, Koji; Maekawa, Toru; Inoue, Akira

    2011-01-01

    In this study, complexes composed of poly-l-tyrosine (pLT) and single-walled carbon nanotubes (SWCNTs) were produced and the dispersibility of the pLT/SWCNT complexes in water by measuring the ζ potential of the complexes and the turbidity of the solution were investigated. It is found that the absolute value of the ζ potential of the pLT/SWCNT complexes is as high as that of SWCNTs modified with double-stranded DNA (dsDNA) and that the complexes remain stably dispersed in the water at least for two weeks. Thermogravimetry analysis (TGA) and visualization of the surface structures of pLT/SWCNT complexes using an atomic force microscope (AFM) were also carried out. PMID:21711636

  1. Versatile visualization of individual single-walled carbon nanotubes with near-infrared fluorescence microscopy.

    PubMed

    Tsyboulski, Dmitri A; Bachilo, Sergei M; Weisman, R Bruce

    2005-05-01

    Fluorescence microscopy in the near-infrared between 950 and 1600 nm has been developed as a novel method to image and study single-walled carbon nanotubes (SWNTs) in a variety of environments. Intrinsic photoluminescence of disaggregated pristine SWNTs was excited by a diode laser and detected with a two-dimensional InGaAs photodiode array. Individual nanotubes were visualized with a spatial resolution of ca. 1 microm and characterized with polarization measurements and emission spectroscopy. Spatially resolved emission spectra allowed (n,m) identification of single nanotubes and revealed small environmentally induced spectral shifts between segments of long tubes. Nanotube motions in aqueous surfactant were visualized with a time resolution of 50 ms and used to estimate the diffusion coefficient. PMID:15884905

  2. Covalent sidewall functionalization of single-walled carbon nanotubes: a photoreduction approach.

    PubMed

    Wei, Liangming; Zhang, Yafei

    2007-12-12

    Covalent sidewall functionalization of single-walled carbon nanotubes (SWNTs) via photoreduction of aromatic ketones by alcohols is reported for the first time. Irradiation of benzophenone, benzhydrol and SWNTs in benzene resulted in covalent attachment of benzhydrol to the sidewalls of the SWNTs. A variety of tools were used to characterize the functionalized SWNTs. Raman scattering, UV-visible and near-IR spectroscopy confirm the covalent nature of the sidewall functionalization. Attenuated total reflection (ATR) FTIR and NMR provided evidence for attachment of benzhydrol onto the sidewalls of nanotubes. Thermogravimetric analysis (TGA) showed that the degree of functionalization was about one benzhydrol in 52 sidewall carbons. A long-chain hydrocarbon marker (n-C(18)H(35)) was also grafted onto the functional groups by esterification reaction for high-resolution TEM (HRTEM) visualization. PMID:20442484

  3. Electrochemical lithium-ion storage properties of quinone molecules encapsulated in single-walled carbon nanotubes.

    PubMed

    Ishii, Yosuke; Tashiro, Kosuke; Hosoe, Kento; Al-Zubaidi, Ayar; Kawasaki, Shinji

    2016-04-21

    We investigated the electrochemical lithium-ion storage properties of 9,10-anthraquinone (AQ) and 9,10-phenanthrenequinone (PhQ) molecules encapsulated in the inner hollow core of single-walled carbon nanotubes (SWCNTs). The structural properties of the obtained encapsulated systems were characterized by electron microscopy, synchrotron powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. We found that almost all quinone molecules encapsulated in the SWCNTs can store Li-ions reversibly. Interestingly, the undesired capacity fading, which comes from the dissolution of quinone molecules into the electrolyte, was suppressed by the encapsulation. It was also found that the overpotential of AQ was decreased by the encapsulation, probably due to the high-electric conductivity of SWCNTs. PMID:27030581

  4. Chirality Separation of Single-Wall Carbon Nanotubes using Aqueous Two-Phase Extraction

    NASA Astrophysics Data System (ADS)

    Fagan, Jeffrey

    2014-03-01

    Aqueous two-phase extraction (ATPE) was recently demonstrated to enable the separation of individual species of single-wall carbon nanotubes (SWCNTs) across the separated phases. In this presentation I will describe the use of a dextran - polyethylene glycol aqueous two-phase system along with a separation scheme of varying surfactant concentrations to enable isolation at high purity of specific small diameter SWCNT species. Separation by ATPE is rapid and robust, with a remarkable tunability that allows isolation of most single nanotube chiralities at high purity. Choice of surfactant(s), temperature, polymer concentrations, and the addition of small molecule salts can all be used to tune the exact partitioning of single SWCNT species between the two phases.

  5. Fabrication of single-walled carbon nanohorns containing iodine and cesium

    SciTech Connect

    Cho, J. H.; Lim, S. T.; Huh, S. R.; Kim, G. H.

    2012-02-15

    Iodine and cesium atoms were encapsulated in single-walled carbon nanohorns (SWCNHs). Atom encapsulation was carried out with sequential plasma aided procedures which consisted of opening SWCNH tips with an oxygen plasma, atom insertion in an iodine-mixed or cesium-mixed argon plasma, and closing the open tip in an argon plasma. Results reveal that oxidation plays a role in the tip opening procedure, and capillary forces are the driving force for the permeation of the atoms through the open tip of the SWCNHs. The open tip of the atom inserted SWCNH can be closed under the ion irradiation. It demonstrated the fabrication process of encapsulating atoms in SWCNH by using the sequential plasma assisted processes.

  6. Thermal expansion of single-walled carbon nanotube (SWNT) bundles: X-ray diffraction studies

    NASA Astrophysics Data System (ADS)

    Maniwa, Yutaka; Fujiwara, Ryuji; Kira, Hiroshi; Tou, Hideki; Kataura, Hiromichi; Suzuki, Shinzo; Achiba, Yohji; Nishibori, Eiji; Takata, Masaki; Sakata, Makoto; Fujiwara, Akihiko; Suematsu, Hiroyoshi

    2001-12-01

    Thermal expansion coefficient in single-walled carbon nanotube bundles was determined as (-0.15+/-0.20)×10-5 (1/K) for the tube diameter and (0.75+/-0.25)×10-5 (1/K) for the triangular lattice constant by means of x-ray scattering between 300 K to 950 K. The value for the intertube gap was (4.2+/-1.4)×10-5 (1/K), which is larger than 2.6×10-5 (1/K) for the c-axis thermal expansion in graphite. The results reveal the presence of a remarkably larger lattice anharmonicity in nanotube bundles than that of graphite. The small value for the tube diameter is consistent with the seamless tube structure formed by a strong covalent bond between carbon atoms comparable to that in graphite.

  7. Three-dimensional polymeric structures of single-wall carbon nanotubes.

    PubMed

    Lian, Chao-Sheng; Wang, Jian-Tao

    2014-05-28

    We explore by ab initio calculations the possible crystalline phases of polymerized single-wall carbon nanotubes (P-SWNTs) and determine their structural, elastic, and electronic properties. Based on direct cross-linking and intertube sliding-assisted cross-linking mechanisms, we have identified a series of stable three-dimensional polymeric structures for the zigzag nanotubes up to (10,0). Among proposed P-SWNT phases, the structures with favorable diamond-like sp(3) intertube bonding configuration and small tube cross-section distortion are found to be the most energetically stable ones. These polymeric crystalline phases exhibit high bulk and shear moduli superior to SWNT bundles, and show metallic or semiconducting properties depending on the diameter of constituent tubes. We also propose by hydrostatic pressure simulations that the intertube sliding between van der Waals bonded nanotubes may be an effective route to promote the polymerization of SWNTs under pressure. PMID:24880313

  8. Enzymatic formation of carbohydrate rings catalyzed by single-walled carbon nanotubes.

    PubMed

    Hyun, Moon Seop; Park, Jong Pil; Seo, Dongkyun; Chang, Sung-Jin; Lee, Seok Jae; Lee, Sang Yup; Kwak, Kyungwon; Park, Tae Jung

    2016-05-01

    Macrocyclic carbohydrate rings were formed via enzymatic reactions around single-walled carbon nanotubes (SWNTs) as a catalyst. Cyclodextrin glucanotransferase, starch substrate and SWNTs were reacted in buffer solution to yield cyclodextrin (CD) rings wrapped around individual SWNTs. Atomic force microscopy showed the resulting complexes to be rings of 12-50 nm in diameter, which were highly soluble and dispersed in aqueous solution. They were further characterized by Raman and Fourier transform infrared spectroscopy and molecular simulation using density functional theory calculation. In the absence of SWNT, hydrogen bonding between glucose units determines the structure of maltose (the precursor of CD) and produces the curvature along the glucose chain. Wrapping SWNT along the short axis was preferred with curvature in the presence of SWNTs and with the hydrophobic interactions between the SWNTs and CD molecules. This synthetic approach may be useful for the functionalization of carbon nanotubes for development of nanostructures. PMID:26946491

  9. High rate capacitive performance of single-walled carbon nanotube aerogels

    SciTech Connect

    Van Aken, Katherine L.; Pérez, Carlos R.; Oh, Youngseok; Beidaghi, Majid; Joo Jeong, Yeon; Islam, Mohammad F.; Gogotsi, Yury

    2015-05-30

    Single-walled carbon nanotube (SWCNT) aerogels produced by critical-point-drying of wet-gel precursors exhibit unique properties, such as high surface-area-to-volume and strength-to-weight ratios. They are free-standing, are binder-free, and can be scaled to thicknesses of more than 1 mm. In this paper, we examine the electric double layer capacitive behavior of these materials using a common room temperature ionic liquid electrolyte, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI). Electrochemical performance is assessed through galvanostatic cycling, cyclic voltammetry and impedance spectroscopy. Results indicate stable capacitive performance over 10,000 cycles as well as an impressive performance at high charge and discharge rates, due to accessible pore networks and enhanced electronic and ionic conductivities of SWCNT aerogels. Finally, these materials can find applications in mechanically compressible and flexible supercapacitor devices with high power requirements.

  10. Anomalous pressure behavior of tangential modes in single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Wang, Ru-Zhi; Wang, Yu-Fang; Song, Xue-Mei; Wang, Bo; Yan, Hui

    2007-07-01

    Using molecular-dynamics simulations and the force-constant model, we have studied the Raman-active tangential modes (TMs) of a (10,0) single-wall carbon nanotube under hydrostatic pressure. With increasing pressure, the atomic motions in the three TMs present obvious diversities. The pressure derivative of E1g , A1g , and E2g mode frequencies shows an increased value (dωE1g/dP>0) , a constant value (dωA1g/dP˜0) , and a negative value (dωE2g/dP<0) above 5.3GPa , respectively. The intrinsic characteristics of TMs consumedly help us understand the essence of the experimental T band of CNT. The anomalous pressure behavior of the TM frequencies may originate from the tube symmetry alteration from D10h to D2h then to C2h .

  11. Photon antibunching in single-walled carbon nanotubes at telecommunication wavelengths and room temperature

    SciTech Connect

    Endo, Takumi Ishi-Hayase, Junko; Maki, Hideyuki

    2015-03-16

    We investigated the photoluminescence of individual air-suspended single-walled carbon nanotubes (SWNTs) from 6 to 300 K. Time-resolved and antibunching measurements over the telecommunication wavelength range were performed using a superconducting single-photon detector. We detected moderate temperature independent antibunching behavior over the whole temperature range studied. To investigate the exciton dynamics, which is responsible for the antibunching behavior, we measured excitation-power and temperature dependence of the photoluminescence spectra and lifetime decay curves. These measurements suggested an exciton confinement effect that is likely caused by high-dielectric amorphous carbon surrounding the SWNTs. These results indicate that SWNTs are good candidates for light sources in quantum communication technologies operating in the telecommunication wavelength range and at room temperature.

  12. Growth dynamics of inner tubes inside cobaltocene-filled single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kharlamova, M. V.; Kramberger, Christian; Saito, Takeshi; Shiozawa, Hidetsugu; Pichler, Thomas

    2016-08-01

    We have synthesized cobaltocene-filled 1.7-nm-mean diameter single-walled carbon nanotubes (SWCNTs) and transformed them into double-walled carbon nanotubes by annealing at temperatures between 500 and 1000 °C for 2 h in vacuum. We analyze the temperature-dependent inner tube growth inside the filled SWCNTs by Raman spectroscopy. The changes in intensity of the Raman peaks of inner tubes with the diameters ranging from 0.832 to 1.321 nm with increasing annealing temperature are traced. It is revealed that the growth temperatures of larger diameter inner tubes are higher than the ones of smaller diameter tubes. A decrease in the diameter of the inner tubes by ~0.4 nm leads to a decrease in the growth temperature by ~200 °C.

  13. The first atomistic modelling-aided reproduction of morphologically defective single walled carbon nanohorns.

    PubMed

    Furmaniak, Sylwester; Terzyk, Artur P; Kaneko, Katsumi; Gauden, Piotr A; Kowlaczyk, Piotr; Itoh, Tsutomu

    2013-01-28

    A new modelling-aided approach for the atomistic model of single walled carbon nanohorn (SWNH) creation is presented, based on experimental evidence, on realistic potential of carbon-carbon interactions and on molecular simulations. A new model of SWNHs is next used to predict Ar adsorption properties and to check the molecular fundamentals of the adsorption mechanism. The influence of the apex angle value, nanohorn diameter and nanohorn length on the shapes of isotherms, enthalpy, high resolution α(s)-plots and adsorption potential distribution curves is checked. Finally the comparison with new experimental Ar adsorption results is shown and the conclusions on the porosity of real SWNH aggregates are given. PMID:23229231

  14. Coupling between flexural modes in free vibration of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Liu, Rumeng; Wang, Lifeng

    2015-12-01

    The nonlinear thermal vibration behavior of a single-walled carbon nanotube (SWCNT) is investigated by molecular dynamics simulation and a nonlinear, nonplanar beam model. Whirling motion with energy transfer between flexural motions is found in the free vibration of the SWCNT excited by the thermal motion of atoms where the geometric nonlinearity is significant. A nonlinear, nonplanar beam model considering the coupling in two vertical vibrational directions is presented to explain the whirling motion of the SWCNT. Energy in different vibrational modes is not equal even over a time scale of tens of nanoseconds, which is much larger than the period of fundamental natural vibration of the SWCNT at equilibrium state. The energy of different modes becomes equal when the time scale increases to the microsecond range.

  15. Molecular interactions on single-walled carbon nanotubes revealed by high-resolution transmission microscopy

    NASA Astrophysics Data System (ADS)

    Umeyama, Tomokazu; Baek, Jinseok; Sato, Yuta; Suenaga, Kazu; Abou-Chahine, Fawzi; Tkachenko, Nikolai V.; Lemmetyinen, Helge; Imahori, Hiroshi

    2015-07-01

    The close solid-state structure-property relationships of organic π-aromatic molecules have attracted interest due to their implications for the design of organic functional materials. In particular, a dimeric structure, that is, a unit consisting of two molecules, is required for precisely evaluating intermolecular interactions. Here, we show that the sidewall of a single-walled carbon nanotube (SWNT) represents a unique molecular dimer platform that can be directly visualized using high-resolution transmission electron microscopy. Pyrene is chosen as the π-aromatic molecule; its dimer is covalently linked to the SWNT sidewalls by aryl addition. Reflecting the orientation and separation of the two molecules, the pyrene dimer on the SWNT exhibits characteristic optical and photophysical properties. The methodology discussed here--form and probe molecular dimers--is highly promising for the creation of unique models and provides indispensable and fundamental information regarding molecular interactions.

  16. Solution phase photolysis of 1,2-dithiane alone and with single-walled carbon nanotubes.

    PubMed

    Engel, Paul S; Gudimetla, Vittal B; Gancheff, Jorge S; Denis, Pablo A

    2012-08-16

    Photolysis of 1,2-dithiane (1) in acetonitrile with single walled carbon nanotubes (SWCNTs) was earlier reported to form thiol-functionalized SWCNTs via the butane-1,4-dithiyl diradical (2). The present study shows that 2 instead undergoes a facile rearrangement to thiophane-2-thiol (6). This photoreaction is clean, rapid, and irreversible under 313 nm irradiation. The secondary photolysis of 6 with SWCNTs at a shorter wavelength (254 nm) leads to 2-thiophanyl radicals 8, which derivatize SWCNTs by covalent attachment. Pyrolysis of the resulting "sulfurized SWCNTs" affords a mixture of organosulfur compounds, including thiophene formed by dehydrogenation. An unknown additional mechanism causes high TGA weight loss and a large incorporation of sulfur. PMID:22874092

  17. Interfacial Surfactant Ordering in Thin Films of SDS-Encapsulated Single-Walled Carbon Nanotubes.

    PubMed

    Das, Sushanta K; Sengupta, Sanghamitra; Velarde, Luis

    2016-01-21

    The molecular self-assembly of surfactants on the surface of single-walled carbon nanotubes (SWCNT) is currently a common strategy for the tuning of nanotube properties and the stabilization of carbon nanotube dispersions. Here, we report direct measurements of the degree of interfacial ordering for sodium dodecyl sulfate (SDS) surfactants adsorbed on colloidal, single-chirality enriched, SWCNTs within a solid film and investigate the dependence of surface alkyl chain order on the surfactant concentration in the precursor solution. The degree of order for the SWCNT-bound SDS molecules, is probed by vibrational sum frequency generation (VSFG) spectroscopy. We find concrete evidence for the presence of highly ordered surface structures at sufficiently high SDS concentrations, attributed here to cylindrical-like micelle assemblies with the SWCNT at the core. As the SDS concentration decreases, the interfacial order is found to decrease as well, generating a more disordered or random adsorption of surfactants on the nanotube surfaces. PMID:26730991

  18. Tuning the driving force for exciton dissociation in single-walled carbon nanotube heterojunctions

    NASA Astrophysics Data System (ADS)

    Ihly, Rachelle; Mistry, Kevin S.; Ferguson, Andrew J.; Clikeman, Tyler T.; Larson, Bryon W.; Reid, Obadiah; Boltalina, Olga V.; Strauss, Steven H.; Rumbles, Garry; Blackburn, Jeffrey L.

    2016-06-01

    Understanding the kinetics and energetics of interfacial electron transfer in molecular systems is crucial for the development of a broad array of technologies, including photovoltaics, solar fuel systems and energy storage. The Marcus formulation for electron transfer relates the thermodynamic driving force and reorganization energy for charge transfer between a given donor/acceptor pair to the kinetics and yield of electron transfer. Here we investigated the influence of the thermodynamic driving force for photoinduced electron transfer (PET) between single-walled carbon nanotubes (SWCNTs) and fullerene derivatives by employing time-resolved microwave conductivity as a sensitive probe of interfacial exciton dissociation. For the first time, we observed the Marcus inverted region (in which driving force exceeds reorganization energy) and quantified the reorganization energy for PET for a model SWCNT/acceptor system. The small reorganization energies (about 130 meV, most of which probably arises from the fullerene acceptors) are beneficial in minimizing energy loss in photoconversion schemes.

  19. Quantum chemistry study on the open end of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hou, Shimin; Shen, Ziyong; Zhao, Xingyu; Xue, Zengquan

    2003-05-01

    Geometrical and electronic structures of open-ended single-walled carbon nanotubes (SWCNTs) are calculated using density functional theory (DFT) with hybrid functional (B3LYP) approximation. Due to different distances between carbon atoms along the edge, reconstruction occurs at the open end of the (4,4) armchair SWCNT, i.e., triple bonds are formed in the carbon atom pairs at the mouth; however, for the (6,0) zigzag SWCNT, electrons in dangling bonds still remain at 'no-bonding' states. The ionization potential (IP) of both (4,4) and (6,0) SWCNTs is increased by their negative intrinsic dipole moments, and localized electronic states existed at both of their open ends.

  20. Investigation of Aromatic/Aliphatic Polyimides as Dispersants for Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Delozier, Donavon M.; Watson, Kent A.; Smith, Joseph G., Jr.; Clancy, Thomas C.; Connell, John W.

    2006-01-01

    Novel aromatic/aliphatic polyimides were prepared from 2,7-diamino-9,9'- dioctylfluorene (AFDA) and aromatic dianhydrides. Upon investigating the effectiveness of these polyimides for dispersing single wall carbon nanotubes (SWNTs) in solution, three were discovered to disperse SWNTs in N,N-dimethylacetamide (DMAc). Two of these polyimides, one from 3,3',4,4'-oxydiphthalic anhydride (ODPA) and one from symmetric 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), were used to prepare nanocomposites. Homogeneous polyimide/SWNT suspensions from both polymers were used in the preparation of films and fibers containing up to 1 wt% SWNTs. The samples were thermally treated to remove residual solvent and the films were characterized for SWNT dispersion by optical and high resolution scanning electron microscopy (HRSEM). Electrical and mechanical properties of the films were also determined. Electrospun fibers were examined by HRSEM to characterize SWNT alignment and orientation.