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Articles 1 - 8 of 8
Full-Text Articles in Biochemical and Biomolecular Engineering
Carbon Nanotube And Cellulose Nanocrystal Hybrid Films, Mingzhe Jiang, Robert Seney, Paul Charles Bayliss, Christopher L. Kitchens
Carbon Nanotube And Cellulose Nanocrystal Hybrid Films, Mingzhe Jiang, Robert Seney, Paul Charles Bayliss, Christopher L. Kitchens
Publications
The use of cellulose nanocrystals (CNC) in high performance coatings is attractive for micro-scale structures or device fabrication due to the anisotropic geometry, however CNC are insulating materials. Carbon nanotubes (CNT) are also rod-shaped nanomaterials that display high mechanical strength and electrical conductivity. The hydrophobic regions of surface-modified CNC can interact with hydrophobic CNT and aid in association between the two anisotropic nanomaterials. The long-range electrostatic repulsion of CNC plays a role in forming a stable CNT and CNC mixture dispersion in water, which is integral to forming a uniform hybrid film. At concentrations favorable for film formation, the multiwalled …
Dna Based Carbon Nanotube Porphyrin Nanohybrids Molecular Recognization And Regeneration, Molly M. Riccitelli, Hanyu Zhang, Jong Hyun Choi
Dna Based Carbon Nanotube Porphyrin Nanohybrids Molecular Recognization And Regeneration, Molly M. Riccitelli, Hanyu Zhang, Jong Hyun Choi
The Summer Undergraduate Research Fellowship (SURF) Symposium
In the search to improve solar cells, scientists are exploring new materials that will provide better current transfer. One material that has emerged as a strong contender is the single walled carbon nanotube (SWNT). Current DNA-SWNT based films combined with chromophores have poor operational lifetimes compared to commercial solar cells. Once exposed to light the chromophore begins to degrade, eventually rendering the solar cell unusable. To solve this problem, we used a method involving multiple steps. First we found which DNA sequences formed structures around the SWNT that could hold the most chromophores by using a spectrophotometer to test the …
Fabrication Of Ph- Or Temperature-Responsive Single Wall Carbon Nanotubes Via A Graft From Photopolymerization, Pu Zhang, David B. Henthorn
Fabrication Of Ph- Or Temperature-Responsive Single Wall Carbon Nanotubes Via A Graft From Photopolymerization, Pu Zhang, David B. Henthorn
Chemical and Biochemical Engineering Faculty Research & Creative Works
An ultraviolet light initiated "graft from" polymerization method to fabricate polymer-functionalized single wall carbon nanotubes (SWNTs) with pendant pH- and temperature-responsive polymer chains is utilized. the attached polymer chains, formed from methacrylic acid and poly (ethylene glycol) methyl ether methacrylate monomers, are well established for its pH-responsive swelling/deswelling behavior. This special property was utilized here to control the aqueous dispersibility of the carbon nanotubes. Furthermore, poly(N-isopropylacrylamide), a temperature-responsive polymer, was utilized in the fabrication of SWNTs whose dispersibility was dependent on solution temperature. the morphology of the polymer-functionalized carbon nanotubes was characterized by scanning electron microscopy (SEM) before and after …
Synthesis Of Pegylated Single Wall Carbon Nanotubes By A Photoinitiated Graft From Polymerization, Pu Zhang, David B. Henthorn
Synthesis Of Pegylated Single Wall Carbon Nanotubes By A Photoinitiated Graft From Polymerization, Pu Zhang, David B. Henthorn
Chemical and Biochemical Engineering Faculty Research & Creative Works
A considerable amount of research has been devoted to carbon nanotubes because of their unique electrical, mechanical, optical, and chemical properties. Here, in this report, we introduce a novel, simple ultraviolet initiated "graft from" polymerization method to synthesize PEGylated carbon nanotubes. This grafting procedure significantly enhanced nanotube aqueous dispersibility and long-term stability in solution. Mass of grafted polymer chains was easily modulated by adjusting polymerization reaction time, and nanomaterials containing up to 80% polymer by weight were synthesized. Nanotube morphology was characterized by SEM, TEM before and after the functionalization. in addition, the covalent bonding of polymer chains to the …
Methanol Electro-Oxidation On Pt-Ru Alloy Nanoparticles Supported On Carbon Nanotubes, Ang Li, Yangchuan Xing
Methanol Electro-Oxidation On Pt-Ru Alloy Nanoparticles Supported On Carbon Nanotubes, Ang Li, Yangchuan Xing
Chemical and Biochemical Engineering Faculty Research & Creative Works
Carbon nanotubes (CNTs) have been investigated in recent years as a catalyst support for proton exchange membrane fuel cells. Improved catalyst activities were observed and attributed to metal-support interactions. We report a study on the kinetics of methanol electro-oxidation on CNT supported Pt-Ru alloy nanoparticles. Alloy catalysts with different compositions, Pt 53Ru 47/CNT, Pt 69Ru 31/CNT and Pt 77Ru 23/CNT, were prepared and investigated in detail. Experiments were conducted at various temperatures, electrode potentials, and methanol concentrations. It was found that the reaction order of methanol electro-oxidation on the PtRu/CNT catalysts was consistent with what has been reported for PtRu …
Simulation Of Nanostructured Electrodes For Polymer Electrolyte Membrane Fuel Cells, Sanjeev M. Rao, Yangchuan Xing
Simulation Of Nanostructured Electrodes For Polymer Electrolyte Membrane Fuel Cells, Sanjeev M. Rao, Yangchuan Xing
Chemical and Biochemical Engineering Faculty Research & Creative Works
Aligned carbon nanotubes (CNTs) with Pt uniformly deposited on them are being considered in fabricating the catalyst layer of polymer electrolyte membrane (PEM) fuel cell electrodes. When coated with a proton conducting polymer (e.g., Nafion) on the Pt/CNTs, each Pt/CNT acts as a nanoelectrode and a collection of such nanoelectrodes constitutes the proposed nanostructured electrodes. Computer modeling was performed for the cathode side, in which both multicomponent and Knudsen diffusion were taken into account. the effect of the nanoelectrode lengths was also studied with catalyst layer thicknesses of 2, 4, 6, and 10 μm. It was observed that shorter lengths …
Effect Of Ph On Ptru Electrocatalysts Prepared Via A Polyol Process On Carbon Nanotubes, Li Ren, Yangchuan Xing
Effect Of Ph On Ptru Electrocatalysts Prepared Via A Polyol Process On Carbon Nanotubes, Li Ren, Yangchuan Xing
Chemical and Biochemical Engineering Faculty Research & Creative Works
This paper reports a study on the pH effects on the PtRu nanoparticles synthesized in a polyol process that were deposited on carbon nanotubes (CNTs) by reducing metal salts using ethylene glycol at various pHs. It was found that the nanoparticle size, composition, and catalytic activity all were sensitive to pH. the nanoparticles decreased in size as the preparation pH increased from 1.6 to 10.0, with the largest size at 2.47 nm and the smallest at 1.13 nm. an exception was found for pH at 0.7, which resulted in an average size of only 1.01 nm. Preparation pH was found …
Electrochemical Durability Of Carbon Nanotubes At 80 °C, Liang Li, Yangchuan Xing
Electrochemical Durability Of Carbon Nanotubes At 80 °C, Liang Li, Yangchuan Xing
Chemical and Biochemical Engineering Faculty Research & Creative Works
Carbon nanotubes (CNTs) have been studied as an alternative catalyst support in polymer electrolyte membrane (PEM) fuel cells. Recent studies showed that CNTs appear to be more resistant to electrochemical corrosion than carbon black (CB). in a previous study, we have demonstrated the room temperature durability of multiwalled CNTs in both non-catalyzed and catalyzed electrochemical oxidations. This paper is to report results conducted at 80 °C-an operational temperature of PEM fuel cells. It was found that multiwalled CNTs are still more resistant than CB at the elevated temperature. However, the electrochemical oxidation rate is more rapid than that at the …