Enhanced electroactive response of unidirectional elastomeric composites with high-dielectric-constant fibers.

A fiber-elastomer composite design with a vastly improved and directional actuation response is proposed for dielectric elastomer actuators. The all-elastomer composites are capable of achieving remarkably high actuation stresses, directional strains, electromechanical coupling efficiencies, and energy densities at relatively low electric fields. Their electromechanical metrics are among the highest reported for this class of electroactive materials.

Hydrogen Peroxide Induced Oxidative Damage on Mineral Density and Mechanical Properties of Bone

ABSTRACT Hydrogen peroxide is a common reactive oxygen species involved in the catalytic mechanism though it is toxic to cells due to its oxidative nature. This work investigates the effects of hydrogen peroxide induced oxidative damage on bone mineral density and mechanical properties of bone which is primarily a composite material composed primarily of collagen fibers and biominerals. Sheep leg bones were exposed to hydrogen peroxide for a week. Bone mineral density was measured by using dual energy X-ray absorptiometry. Compressive modulus tests were applied to bone in order to determine mechanical properties. Our study shows that the hydrogen peroxide induced oxidative stress has negative effects on bone mineral density and stiffness. We observed higher control curve slopes than that of hydrogen peroxide curves which account for lesser stiffness values in the exposed tissue (p<0.05).

Molecular dynamics simulations of interactions between polyanilines in their inclusion complexes with ß-cyclodextrins.

Conductive polymers have several applications such as in flexible displays, solar cells, and biomedical sensors. An inclusion complex of a conductive polymer and cyclodextrin is desired for some applications such as for molecular wires. In this study, different orientations of ß-cyclodextrin rings on a single polyaniline (PANI) chain in an alternating emeraldine form were simulated using molecular dynamics. The simulations were performed in an implicit solvent environment that corresponds to experimental conditions. When the larger opening of the ß-cyclodextrin toroids face the same direction, the cyclodextrins tend to repel each other. Alternating the orientation of the ß-cyclodextrins on the chain causes the ß-cyclodextrin rings to be more attractive to one another and form pairs or stacks of rings. These simulations explain how the ß-cyclodextrins can be used to shield the polyaniline from outside chemical action by analyzing the PANI/cyclodextrin interactions from a molecular perspective.