InterNano Nanomanufacturing Repository
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Permanent Electric Dipole Moments of Carboxyamides in Condensed Media: What Are the Limitations of Theory and Experiment?
No full textElectrostatic properties of proteins are crucial for their functionality. Carboxyamides are small polar groups that, as peptide bonds, are principal structural components of proteins that govern their electrostatic properties. We investigated the medium dependence of the molar polarization and of the permanent dipole moments of amides with different state of alkylation. The experimentally measured and theoretically calculated dipole moments manifested a solvent dependence that increased with the increase in the media polarity. We ascribed the observed enhancement of the amide polarization to the reaction fields in the solvated cavities. Chloroform, for example, caused about a 25% increase in the amide dipole moments determined for vacuum, as the experimental and theoretical results demonstrated. Another chlorinated solvent, 1,1,2,2-tetrachloroethane, however, caused an "abnormal" increase in the experimentally measured amide dipoles, which the theoretical approaches we used could not readily quantify. We showed and discussed alternatives for addressing such discrepancies between theory and experiment
Gold nanoparticle-polymer/biopolymer complexes for protein sensing
No full textNanoparticle-based sensor arrays have been used to distinguish a wide range of biomolecular targets through pattern recognition. Such biosensors require selective receptors that generate a unique response pattern for each analyte. The tunable surface properties of gold nanoparticles make these systems excellent candidates for the recognition process. Likewise, the metallic core makes these particles fluorescence superquenchers, facilitating transduction of the binding event. In this report we analyze the role of gold nanoparticles as receptors in differentiating a diversity of important human proteins, and the role of the polymer/biopolymer fluorescent probes for transducing the binding event. A structure-activity relationship analysis of both the probes and the nanoparticles is presented, providing direction for the engineering of future sensor systems
Large-Scale Graphene Transistors with Enhanced Performance and Reliability Based on Interface Engineering by Phenylsilane Self-Assembled Monolayers
No full textIn this letter, we report the dielectric/graphene interface physics and engineering of large-scale, chemical vapor deposited (CVD) graphene transistors by self-assembling a molecular-scale organosilane monolayer onto the dielectric surface. We show that phenyl-alkyl-terminated self-assembled monolayers (SAM) at the dielectric/graphene interface consistently improve the graphene device performance and reliability. The extrinsic field-effect mobility of large-scale CVD graphene transistors on the phenyl-SAM engineered dielectric is currently up to 2500 cm2/(V s) at room temperature, considerably higher than the counterparts without the SAM. In addition, significant reduction on the bias stress instability and hysteresis is achieved by the SAM-based interface engineering. Further analysis reveals that charge injection from graphene to the dielectric/graphene interface dominates the observed hysteresis behavior. For both graphene transistors with and without SAMs, the bias stress stability, that is, Dirac point shift under bias stress, is well described by the stretched exponential model with its fitting parameters clearly indicating different interface properties
Effect of Processing Parameters on the Electrophoretic Deposition of Carbon Black Nanoparticles in Moderately Viscous Systems
No full textCongressional Subcommittee Explores Impact and Economic Benefits of National Nanotechnology Initiative
No full textThis month, the House Science, Space, and Technology Subcommittee on Research and Science Education held a hearing, entitled "Nanotechnology: Oversight of the National Nanotechnology Initiative and Priorities for the Future", to assess the impact of the federal government's investment in the National Nanotechnology Initiative (NNI). In doing so the subcommittee heard key testimony from industry sectors and government officials regarding aspects of the federal investment, including economic impact, jobs creation, global competitiveness, and environmental health and safety, providing guidance to the subcommittee regarding future nanotechnology research and development (R&D) priorities for U.S.
The NNI provides multi-agency coordination overseeing all federal nanotechnology research. The NNI supports the basic research and development of nanotechnology, which has resulted in U.S. leadership in the field, and is now looking to develop roadmaps in areas of critical national needs to maintain U.S. competitiveness. The NNI Supplement to the President's Fiscal Year 2012 Budget includes funding requests from 15 federal agencies investing in nanotechnology, with over a 200 million dollar increase from FY10 levels (+11%). Significant increases have been requested for environmental, health and safety (EHS), solar energy conversion, sustainable nanomanufacturing, and nanoelectronics. In times of budgetary uncertainty, Congress makes efforts to ensure that federal programs provide economic impact. With nanotechnology and nanomanufacturing having the potential to become the next industrial revolution, having significant economic and societal impact, the subcommittee heard testimony supporting key priorities.
Also included: GE Achieves Highest Publicly Reported Efficiency for Thin Film Solar, Earns New Orders and Unveils Plans to Build US Manufacturing Plant, High Speed Water Sterilization Using One-Dimensional Nanostructures, and NanoBusiness Alliance Interview with William Moffit
Ultrathin Coatings on Nano-LiCoO2for Li-Ion Vehicular Applications
No full textTo deploy Li-ion batteries in next-generation vehicles, it is essential to develop electrodes with durability, high energy density, and high power. Here we report a breakthrough in controlled full-electrode nanoscale coatings that enables nanosized materials to cycle with durable high energy and remarkable rate performance. The nanoparticle electrodes are coated with Al2O3 using atomic layer deposition (ALD). The coated nano-LiCoO2 electrodes with 2 ALD cycles deliver a discharge capacity of 133 mAh/g with currents of 1400 mA/g (7.8C), corresponding to a 250% improvement in reversible capacity compared to bare nanoparticles (br-nLCO), when cycled at this high rate. The simple ALD process is broadly applicable and provides new opportunities for the battery industry to design other novel nanostructured electrodes that are highly durable even while cycling at high rate.
Keywords (keywords):
Atomic layer deposition; LiCoO2; rate performance; Li-ion battery; capacity fade; nanotechnolog
