New Approaches to Stretched Film Sample Alignment and Data Collection for Vibrational Linear Dichroism.

Rapid measurements of vibrational linear dichroism (VLD) infrared spectra are shown to be possible by using stretched polymer films and an extension of existing instrumentation designed for vibrational circular dichroism spectroscopy. Earlier techniques can be extended using additional inexpensive polymer substrates to record good-quality VLD spectra of a significantly wider range of compounds with comparatively short sample-preparation times. The polymer substrates used, polyethylene and polytetrafluoroethylene, are commonly available and inexpensive, and samples are more easily prepared than that for many earlier stretched-film and crystal studies.

Fabrication of Graphene-Polymer Nanocomposites Through Ionic Polymerization.

The extraordinary properties of graphene nanosheets (GNS) and the high performance of polymer-based composites have stimulated extensive research in the realm of polymer nanocomposites. This work examines the mechanisms and approach for the production of GNS-polymer composites by first principle ab initio calculations. The results show that GNS functionalized with anionic/cationic moieties can initiate anionic/cationic polymerization reactions, leading to chemically bonded GNS-polymer composites via the established anionic/cationic polymerization schemes.

Fabrication and application of polymer composites comprising carbon nanotubes.

Carbon nanotubes are being used in place of carbon fibers in making composites due to their high strength, high aspect-ratio and excellent thermal and electrical conductivity. Although carbon nanotubes were discovered more than a decade ago, works on preparation of satisfactory composites reinforced by carbon nanotubes have encountered difficulties. This review will discuss some registered patents and relevant papers on the fabrication of carbon nanotube-polymer composites on improving material properties such as electrical conductivity, mechanical strength, and radiation detection which have a broad range of applications in nano-electronic devices, and space and medical elements.

Molecular simulations of the large conductance mechanosensitive (MscL) channel under mechanical loading.

The MscL channel is a mechanosensitive channel which is gated by membrane stress or tension. Here, we describe a series of simulations which apply simulated mechanical stress to a molecular model of the MscL channel using two methods - direct force application to the transmembrane segments, and anisotropic pressure coupling. In the latter simulations, pressures less than that equivalent to a bilayer tension of 12 dyn/cm did not cause the channel to open, while pressures in excess of this value resulted in the channel opening.