Home About us Contact
|
Home About us Contact | ||
|
|
||
SWNTs
Selected AbstractsA New Amperometric Hydrazine Sensor Based on Prussian Blue/Single-walled Carbon Nanotube NanocompositesELECTROANALYSIS, Issue 16 2010Cong Wang Abstract A slow reaction process has been successfully used to synthesize Prussian blue/single-walled carbon nanotubes (PB/SWNTs) nanocomposites. Electrochemical and surface characterization by cyclic voltammetry (CV), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed the presence of PB nanocrystallites on SWNTs. PB/SWNTs modified glassy carbon electrode (GCE) exhibits efficient electron transfer ability and high electrochemical response towards hydrazine. The fabricated hydrazine sensor showed a wide linear range of 2.0×10,6,6.0×10,3,M with a response time less than 4,s and a detection limit of 0.5,,M. PB/SWNTs modified electrochemical sensors are promising candidates for cost-effective in the hydrazine assays. [source] Fabrication, Characterization, and Application of ,Sandwich-Type' Electrode Based on Single-Walled Carbon Nanotubes and Room Temperature Ionic LiquidELECTROANALYSIS, Issue 17 2008Xuzhi Zhang Abstract The much-enhanced electrochemical responses of potassium ferricyanide and methylene blue (MB) were firstly explored at the glassy carbon electrode modified with single-walled carbon nanotubes (SWNT/GCE), indicating the distinct electrochemical activity of SWNTs towards electroactive molecules. A hydrophobic room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), was used as electrode modification material, which presented wide electrochemical windows, proton permeation and selective extraction ability. In consideration with the advantages of SWNTs and RTIL in detecting target molecules (TMs), a novel strategy of ,sandwich,type' electrode was established with TMs confined by RTIL between the SWNT/GCE and the RTIL membrane. The strategy was used for electrochemical detection of ascorbic acid (AA) and dopamine (DA), and detection limits of 400 and 80 fmol could be obtained, respectively. The selective detection of DA in the presence of high amount of AA could also be realized. This protocol presented many attractive advantages towards voltammetric detection of TMs, such as low sample demand, low cost, high sensitivity, and good stability. [source] Paste Electrode Based on Short Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid: Preparation, Characterization and Application in DNA DetectionELECTROANALYSIS, Issue 12 2008Xuzhi Zhang Abstract A paste electrode (SWNT&RTIL PE) has been prepared using carboxylic group-functionalized short single-walled carbon nanotubes (SWNTs) mixed with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6, one kind of room temperature ionic liquid, RTIL). Its electrochemical behavior was investigated by cyclic voltammetry and electrochemical impedance spectroscopy in comparison with the paste electrode using mineral oil as a binder. Results highlighted the advantages of the paste electrode: not only higher conductivity, but also lower potential separation (,Ep), higher peak current (ip) and better reversibility towards dopamine (DA), methylene blue (MB) and K3[Fe(CN)6]. The SWNT&RTIL PE could be used to detect the number of guanine bases and adenine bases contents in per mol oligonucleotides according to the current response in the range of 0.05,2.0,nM. Based on the current response of guanine bases, oligonucleotides could be detected sensitively in the B,R buffer solution with a detection limit of 9.9,pM. The heterogeneous electron transfer rate constant (ks) of guanine bases contents in the oligonucleotides was investigated and its value was 0.90,s,1. In essence the SWNT&RTIL PE showed high sensitivity, reliability, stability and reproducibility for the detection of DNA. [source] Electrochemically Functionalized Single-Walled Carbon Nanotube Gas SensorELECTROANALYSIS, Issue 12 2006Ting Zhang Abstract We demonstrate a facile fabrication method to make chemical gas sensors using single-walled carbon nanotubes (SWNT) electrochemically functionalized with polyaniline (PANI). The potential advantage of this method is to enable targeted functionalization with different materials to allow for creation of high-density individually addressable nanosensor arrays. PANI-SWNT network based sensors were tested for on-line monitoring of ammonia gas. The results show a superior sensitivity of 2.44% ,R/R per ppmv NH3 (which is more than 60 times higher than intrinsic SWNT based sensors), a detection limit as low as 50,ppbv, and good reproducibility upon repeated exposure to 10,ppmv NH3. The typical response time of the sensors at room temperature is on the order of minutes and the recovery time is a few hours. Higher sensitivities were observed at lower temperatures. These results indicate that electrochemical functionalization of SWNTs provides a promising new method of creating highly advanced nanosensors with improved sensitivity, detection limit, and reproducibility. [source] Surfactant-coated single-walled carbon nanotubes as a novel pseudostationary phase in capillary EKCELECTROPHORESIS, Issue 11 2007Beatriz Suárez Abstract The analytical potential of the use of surfactant-coated single-walled carbon nanotubes (SC-SWNTs) as pseudostationary phase in CE is described. The pseudostationary phase shows an efficient alternative in enhancing electrochromatographic resolution of compounds which are capable of interacting with a nanotube surface, such as aromatic compounds. In general, the resolution is enhanced by increasing nanotube concentration in the buffer but the maximum amount of SWNTs that can be added to background electrolyte was found limited by compatibility with the UV/visible detection. As an alternative, a low-extension partial filling was used, consisting of the introduction into the capillary of concentrated SC-SWNT, just before the sample, with a plug length similar to the sample one. This has been showed as a reliable procedure in increasing resolution and sensitivity by sweeping phenomena. Finally, the potential of SC-SWNTs to perform chiral separations is discussed. [source] Neurite Outgrowth on Nanocomposite Scaffolds Synthesized from PLGA and Carboxylated Carbon Nanotubes,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Hyun Jung Lee Abstract Carbon nanotubes (CNTs) have been suggested as suitable materials for biomedical applications, especially in the neural area. It is essential not only to investigate the biocompatibility of CNTs with the neural system but also to determine proper methods for applying CNTs to neuronal growth. This work represents the first application of CNTs by electrospun poly(D,L -lactic-co-glycolic acid) (PLGA) scaffolds for a neural system. We synthesized electrospun nanocomposites of PLGA and single-walled carbon nanotubes functionalized by carboxylic acid groups (c- SWNTs), and investigated neurite outgrowth from SH-SY5Y cells on these nanocomposites as compared to that on fibrous PLGA alone. Cells on our PLGA/c -SWNT nanocomposite showed significantly enhanced mitochondrial function and neurite outgrowth compared to cells on PLGA alone. We concluded that c -SWNTs incorporated into fibrous PLGA scaffolds exerted a positive role on the health of neural cells. [source] Single-Walled Carbon Nanotube/Trititanate Nanotube Composite Fibers,ADVANCED ENGINEERING MATERIALS, Issue 7 2009Chonlada Dechakiatkrai For the first time, single-walled carbon nanotubes were dispersed with titanate nanotubes using bio-polymers. Direct injection (wet spinning) of the stable suspension of H2Ti3O7 and SWNTs into coagulation baths produced fibers. The mechanical and electrical properties along with surface morphology and electrochemistry of the resulting fibers were investigated. The presence of SWNTs clearly improved the mechanical and electrical properties of the composite fibers compared with H2Ti3O7 alone. [source] Selective Electrochemical Etching of Single-Walled Carbon NanotubesADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Dacheng Wei Abstract Single-walled carbon nanotubes (SWNTs) are a promising material for future nanotechnology. However, their applications are still limited in success because of the co-existence of metallic SWNTs and semiconducting SWNTs produced samples. Here, electrochemical etching, which shows both diameter and electrical selectivity, is demonstrated to remove SWNTs. With the aid of a back-gate electric field, selective removal of metallic SWNTs is realized, resulting in high-performance SWNT field-effect transistors with pure semiconducting SWNT channels. Moreover, electrochemical etching is realized on a selective area. These findings would be valuable for research and the application of SWNTs in electrochemistry and in electronic devices. [source] Effect of SWNT Defects on the Electron Transfer Properties in P3HT/SWNT Hybrid Materials,ADVANCED FUNCTIONAL MATERIALS, Issue 18 2008Jianxin Geng Abstract Poly(3-hexylthiophene) (P3HT) hybrids with single-walled carbon nanotubes (SWNTs) were prepared using a series of SWNTs with various defect contents on their surfaces. The hybrids were synthesized by exploiting the ,,, interaction between P3HT and the SWNTs, resulting in efficient dispersion of the carbon nanotubes in the P3HT solution. UV-visible and photoluminescence (PL) spectra showed that the carbon nanotubes quench the PL of P3HT in the hybrids, indicating that electron transfer occurs from photo-excited P3HT to the SWNTs. This electron transfer from P3HT to carbon nanotubes was disrupted by the presence of defects on the SWNT surfaces. However, the PL lifetime of P3HT in the hybrids was found to be the same as that of pure P3HT in solution, indicating the formation of a ground-state non-fluorescent complex of P3HT/SWNTs. [source] A Versatile, Molecular Engineering Approach to Simultaneously Enhanced, Multifunctional Carbon-Nanotube, Polymer Composites,ADVANCED FUNCTIONAL MATERIALS, Issue 1 2006J. Chen Abstract Single-walled carbon nanotubes (SWNTs) are recognized as the ultimate carbon fibers for high-performance, multifunctional composites. The remarkable multifunctional properties of pristine SWNTs have proven, however, difficult to harness simultaneously in polymer composites, a problem that arises largely because of the smooth surface of the carbon nanotubes (i.e., sidewalls), which is incompatible with most solvents and polymers, and leads to a poor dispersion of SWNTs in polymer matrices, and weak SWNT,polymer adhesion. Although covalently functionalized carbon nanotubes are excellent reinforcements for mechanically strong composites, they are usually less attractive fillers for multifunctional composites, because the covalent functionalization of nanotube sidewalls can considerably alter, or even destroy, the nanotubes' desirable intrinsic properties. We report for the first time that the molecular engineering of the interface between non-covalently functionalized SWNTs and the surrounding polymer matrix is crucial for achieving the dramatic and simultaneous enhancement in mechanical and electrical properties of SWNT,polymer composites. We demonstrate that the molecularly designed interface of SWNT,matrix polymer leads to multifunctional SWNT,polymer composite films stronger than pure aluminum, but with only half the density of aluminum, while concurrently providing electroconductivity and room-temperature solution processability. [source] Molecular dynamics in the formation process of single-walled carbon nanotubesHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2003Yasushi Shibuta Abstract The mechanism of the nucleation and formation of single-walled carbon nanotubes (SWNTs) was investigated using molecular dynamics simulations. When the initial state was chosen so that carbon and nickel atoms were randomly distributed in a simulation domain, the formation of a random cage structure made up of carbon atoms, which had a few nickel atoms inside it, was observed by 6 ns. The nickel atoms, which move inside or on the surface of the cage, were seen to be preventing the complete closure of the cage and its anneal into the fullerene structure. Further, in order to observe a longer time-scale growth process, the simulation cell was artificially shrunk by the progress of simulation so that collisions between precursor clusters were promoted to comply with the limitation in the calculation time. Collisions of the imperfect random-cage clusters led to an elongated tubular cage structure, which could be regarded as an initiation of SWNTs. The simulation results were compared with FT-ICR mass spectra of the positive clusters generated by a laser-vaporization supersonic-expansion cluster beam source. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 690,699, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10123 [source] Aligned, Ultralong Single-Walled Carbon Nanotubes: From Synthesis, Sorting, to Electronic DevicesADVANCED MATERIALS, Issue 21 2010Zhongfan Liu Abstract Aligned, ultralong single-walled carbon nanotubes (SWNTs) represent attractive building blocks for nanoelectronics. The structural uniformity along their tube axis and well-ordered two-dimensional architectures on wafer surfaces may provide a straightforward platform for fabricating high-performance SWNT-based integrated circuits. On the way towards future nanoelectronic devices, many challenges for such a specific system also exist. This Review summarizes the recent advances in the synthesis, identification and sorting, transfer printing and manipulation, device fabrication and integration of aligned, ultralong SWNTs in detail together with discussion on their major challenges and opportunities for their practical application. [source] Stretchable, Large-area Organic ElectronicsADVANCED MATERIALS, Issue 20 2010Tsuyoshi Sekitani Abstract Stretchability will significantly expand the application scope of electronics, particularly large-area electronics,displays, sensors, and actuators. If arbitrary surfaces and movable parts could be covered with stretchable electronics, which is impossible with conventional electronics, new classes of applications are expected to emerge. A large hurdle is manufacturing electrical wiring with high conductivity, high stretchability, and large-area compatibility. This Review describes stretchable, large-area electronics based on organic field-effect transistors for applications to sensors and displays. First, novel net-shaped organic transistors are employed to realize stretchable, large-area sensor networks that detect distributions of pressure and temperature simultaneously. The whole system is functional even when it is stretched by 25%. In order to further improve stretchability, printable elastic conductors are developed by dispersing single-walled carbon nanotubes (SWNTs) as dopants uniformly in rubbers. Further, we describe integration of printable elastic conductors with organic transistors to construct a rubber-like stretchable active matrix for large-area sensor and display applications. Finally, we will discuss the future prospects of stretchable, large-area electronics with delineating a picture of the next-generation human/machine interfaces from the aspect of materials science and electronic engineering. [source] Electric-Field Enhancement of Photovoltaic Devices: A Third Reason for the Increase in the Efficiency of Photovoltaic Devices by Carbon NanotubesADVANCED MATERIALS, Issue 20 2010Wonjoo Lee Electric-field enhancement of photovoltaic devices by carbon nanotubes (CNTs) is reported as a third alternative for increasing the efficiency of photovoltaic devices. Due to the formation of an efficient electronic energy-cascade structure, the decrease of the interfacial resistance, and the improvement of the electrical field, the power-conversion efficiency of solar cells was increased by 22% in the presence of the SWNTs. [source] Nanostructured Fe3O4/SWNT Electrode: Binder-Free and High-Rate Li-Ion AnodeADVANCED MATERIALS, Issue 20 2010Chunmei Ban Utilizing Fe3O4 nanorods as the active Li+ storage material and 5,wt% carbon single-walled nanotubes (SWNTs) as a "conductive net," a Li-ion anode with a high reversible capacity of 1000,mAh,g,1 (,2000,mAh,cm,3) at C rate is demonstrated. The electrodes exhibit high-rate capability and stable capacities of 800,mAh,g,1 at 5C and ,600,mAh,g,1 at 10C. [source] Vertically Aligned Single-Walled Carbon Nanotubes by Chemical Assembly , Methodology, Properties, and ApplicationsADVANCED MATERIALS, Issue 13 2010Peng Diao Abstract Single-walled carbon nanotubes (SWNTs), as one of the most promising one-dimension nanomaterials due to its unique structure, peculiar chemical, mechanical, thermal, and electronic properties, have long been considered as an important building block to construct ordered alignments. Vertically aligned SWNTs (v-SWNTs) have been successfully prepared by using direct growth and chemical assembly strategies. In this review, we focus explicitly on the v-SWNTs fabricated via chemical assembly strategy. We provide the readers with a full and systematic summary covering the advances in all aspects of this area, including various approaches for the preparation of v-SWNTs using chemical assembly techniques, characterization, assembly kinetics, and electrochemical properties of v-SWNTs. We also review the applications of v-SWNTs in electrochemical and bioelectrochemical sensors, photoelectric conversion, and scanning probe microscopy. [source] Solution-Processable Carbon Nanotubes for Semiconducting Thin-Film Transistor DevicesADVANCED MATERIALS, Issue 11 2010Chun Wei Lee CoMoCat single-walled carbon nanotubes (SWNTs) treated with diazonium salts can be used to fabricate solution-processable field-effect transistors (FETs) with a full semiconductor device yield. By increasing the network thickness, the effective mobility of the devices can be raised to ,10 cm2 V,1 s,1 while keeping the on,off ratio higher than 5000. The removal of impurities is essential to achieve high-on,off-ratio devices. This approach is promising for preparation of SWNT inks for printing high-performance devices in flexible electronics. [source] A Facile, Low-Cost, and Scalable Method of Selective Etching of Semiconducting Single-Walled Carbon Nanotubes by a Gas ReactionADVANCED MATERIALS, Issue 7 2009Hongliang Zhang A facile, scalable, and low-cost gas-treatment method for selectively etching semiconductor single-walled carbon nanotubes (SWNTs) is developed. Using SO3 gas as the etchant at a temperature of 400 °C, semiconductor SWNTs can be selectively and efficiently removed, and after this gas treatment samples enriched with metallic SWNTs can be obtained. [source] Functional Covalent Chemistry of Carbon Nanotube SurfacesADVANCED MATERIALS, Issue 6 2009Xiaohui Peng Abstract In this Progress Report, we update covalent chemical strategies commonly used for the focused functionalization of single-walled carbon nanotube (SWNT) surfaces. In recent years, SWNTs have been treated as legitimate nanoscale chemical reagents. Hence, herein we seek to understand, from a structural and mechanistic perspective, the breadth and types of controlled covalent reactions SWNTs can undergo in solution phase, not only at ends and defect sites but also along sidewalls. We explore advances in the formation of nanotube derivatives that essentially maintain and even enhance their performance metrics after precise chemical modification. We especially highlight molecular insights (and corresponding correlation with properties) into the binding of functional moieties onto carbon nanotube surfaces. Controllable chemical functionalization suggests that the unique optical, electronic, and mechanical properties of SWNTs can be much more readily tuned than ever before, with key implications for the generation of truly functional nanoscale working devices. [source] Ultrathin Films of Single-Walled Carbon Nanotubes for Electronics and Sensors: A Review of Fundamental and Applied AspectsADVANCED MATERIALS, Issue 1 2009Qing Cao Abstract Ultrathin films of single-walled carbon nanotubes (SWNTs) represent an attractive, emerging class of material, with properties that can approach the exceptional electrical, mechanical, and optical characteristics of individual SWNTs, in a format that, unlike isolated tubes, is readily suitable for scalable integration into devices. These features suggest the potential for realistic applications as conducting or semiconducting layers in diverse types of electronic, optoelectronic and sensor systems. This article reviews recent advances in assembly techniques for forming such films, modeling and experimental work that reveals their collective properties, and engineering aspects of implementation in sensors and in electronic devices and circuits with various levels of complexity. A concluding discussion provides some perspectives on possibilities for future work in fundamental and applied aspects. [source] Reversible Infrared Actuation of Carbon Nanotube,Liquid Crystalline Elastomer Nanocomposites,ADVANCED MATERIALS, Issue 12 2008Liqiang Yang Nanocomposite films comprising polymer-functionalized single-walled carbon-nanotubes (SWNTs) and liquid crystal elastomers (LCEs) show a reversible IR-induced strain (,,30%) at very low SWNT loading levels (,0.2 wt%). SWNTs can efficiently transform absorbed IR light into thermal energy, thereby serving as a nanoscale heat-source and thermal- conduction pathway. The absorbed thermal-energy induced a nematic, isotropic phase-transition, generating a shape change in the nanocomposite film. [source] Light-Induced Charge Transfer in Pyrene/CdSe-SWNT Hybrids,ADVANCED MATERIALS, Issue 5 2008L. Hu Hybrids of pyrene/CdSe-single-walled carbon nanotubes (SWNTs) are fabricated by self-assembling surface-functionalized pyrene/CdSe nanoparticles onto CVD-grown SWNTs. Light- induced charge transfer from the nanoparticles to the nanotubes is determined from the threshold voltage shift of a SWNT field-effect transistor, yielding a maximum value of 2.2 electrons per pyrene/CdSe nanoparticle. [source] Enhanced Optical Limiting Effects in Porphyrin-Covalently Functionalized Single-Walled Carbon Nanotubes,ADVANCED MATERIALS, Issue 3 2008Z.-B. Liu Single-walled carbon nanotubes covalently functionalized with porphyrins present enhanced optical limiting effects. Both porphyrins and SWNTs are good candidates for optical limiting applications. The porphyrin-covalently functionalized SWNTs offer superior performance to C60, the individual SWNTs, and porphyrins because of a combined nonlinear mechanism and photoinduced electron or energy transfer between the porphyrin moiety and the SWNTs. [source] DNA-Wrapped Single Walled Carbon Nanotubes as Rigid Templates for Assembling Linear Gold Nanoparticle Arrays,ADVANCED MATERIALS, Issue 11 2007X. Han Nanotube templates assembly: Water-soluble conjugates between gold nanoparticles and DNA-wrapped single-walled carbon nanotubes (SWNTs), as shown in the figure, are constructed based on a self-assembly strategy that does not require any chemical modifications to the sidewalls of the SWNTs, which minimizes the possibility of changes to their structure and properties. The success of assembling Au nanoparticles (AuNPs) onto SWNTs paves a way for further decoration of AuNPs on SWNTs to achieve multifunctionalities. [source] Length-Dependent Uptake of DNA-Wrapped Single-Walled Carbon Nanotubes,ADVANCED MATERIALS, Issue 7 2007L. Becker A length threshold for cell uptake of DNA-wrapped single-walled carbon nanotubes (SWNTs) by human lung fibroblasts (IMR90) is identified. Competitive uptake experiments with well-defined and characterized length fractions show that SWNTs above the length threshold are excluded from the cell, whereas SWNTs labeled with Cy3-derivatized DNA below the threshold are able to access the cell interior, as shown in the fluorescence image and on the cover. [source] Synthesis of SiCNO Nanowires Through Heat-Treatment of Polymer-Functionalized Single-Walled Carbon Nanotubes,ADVANCED MATERIALS, Issue 13 2004R.-G. Duan SiCNO nanowires (see Figure) have been successfully synthesized by heat-treatment of polymer-functionalized single-walled carbon nanotubes (SWNTs). The tangled networks of SWNT ropes associate tightly and uniformly with the polymer precursor, most likely via chemical bonds between the polymer and the SWNT surface. The SWNTs act as a template to confine the reaction with the polymer in the synthesis of the nanowires. [source] A molecular dynamics simulation of air adsorption in single-walled carbon nanotube bundlesINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 10 2008Víctor Rojas Cervellera Abstract The physisorption of air in single-walled carbon nanotubes (SWNTs) is studied employing molecular dynamics. The effect of the nanotube diameter in the gas adsorption capacity of SWNT bundles has been investigated using (10,0), (15,0), and (20,0) SWNTs finding an increasing load capacity. The O2:N2 ratio in the nanotube bundles is analyzed in detail as well, comparing it to that in the gaseous bulk. The air contained in the carbon nanostructures has a larger content in O2 than the bulk air, thus providing a possible application of carbon nanotubes as molecular filters. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Preparation and properties of the single-walled carbon nanotube/cellulose nanocomposites using N -methylmorpholine- N -oxide monohydrateJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Dong-Hun Kim Abstract Single-walled carbon nanotube (SWNT)/cellulose nanocomposite films were prepared using N -methylmorpholine- N -oxide (NMMO) monohydrate as a dispersing agent for the acid-treated SWNTs (A-SWNTs) as well as a cellulose solvent. The A-SWNTs were dispersed in both NMMO monohydrate and the nanocomposite film (as confirmed by scanning electron microscopy) because of the strong hydrogen bonds of the A-SWNTs with NMMO and cellulose. The mechanical properties, thermal properties, and electric conductivity of the nanocomposite films were improved by adding a small amount of the A-SWNTs to the cellulose. For example, by adding 1 wt % of the A-SWNTs to the cellulose, tensile strain at break point, Young's modulus, and toughness increased , 5.4, , 2.2, and , 6 times, respectively, the degradation temperature increased to 9°C as compared with those of the pure cellulose film, and the electric conductivities at , (the wt % of A-SWNTs in the composite) = 1 and 9 were 4.97 × 10,4 and 3.74 × 10,2 S/cm, respectively. Thus, the A-SWNT/cellulose nanocomposites are a promising material and can be used for many applications, such as toughened Lyocell fibers, transparent electrodes, and soforth. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Phase separation of polymer-functionalized SWNTs within a PMMA/polystyrene blendJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2009James D. Mayo Abstract Phase separation of polystyrene (PS) and poly(methyl methacrylate) (PMMA) blends was used as a means to segregate PS- or PMMA-functionalized single-walled carbon nanotubes (SWNTs) in thin films. Dilute solutions (5 wt % in THF) of 1:1 PS/PMMA blends containing the functionalized nanotubes were spin cast and annealed at 180 °C for 12 h. Two different polymer molecular weights were used (Mn = 8000 or Mn = 22,000), and were of approximately equivalent molecular weight to those attached to the surface of the nanotubes. Nanotube functionalization was accomplished using the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition, in which alkyne-decorated nanotubes were coupled with azide-terminated polymers, resulting in polymer-SWNT conjugates that were soluble in THF. Characterization of the annealed films by scanning Raman spectroscopy, which utilized the unique Raman fingerprint of carbon nanotubes, enabled accurate mapping of the functionalized SWNTs within the films relative to the two phase-separated polymers. It was found that nanotube localization within the phase-separated polymer films was influenced by the type of polymer attached to the nanotube surface, as well as its molecular weight. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 450,458, 2009 [source] Preparation of single-walled carbon nanotubes-induced poly(p -oxybenzoyl) crystalsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2008Kazufumi Kobashi Abstract Crystallization of oligomers was applied for the preparation of single-walled carbon nanotubes (SWNTs)/poly(p -oxybenzoyl) (POB) crystals using SWNTs as a nucleating agent. Polymerization conditions were investigated to induce the crystallization of POB oligomers through SWNTs. SWNTs/POB plate-like or lozenge-shaped crystals were successfully prepared by direct polymerization of p -hydroxybenzoic acid (HBA) in a mixed solvent of DMF/Py with TsCl in the presence of functionalized SWNTs. The size of the plate-like crystals were ,200 nm to 3 ,m. The crystals consisted of some layers, ,3 nm thick plates. Model reactions showed that esterification reactions proceed between functionalized SWNTs and HBA monomers in the polymerization system. The obtained crystals exhibited unique morphology and high crystallinity, producing a novel SWNT/POB hybrid. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1265,1277, 2008 [source] | |||||||||||||||||||||||||||||||