Stretchable Conductive Hybrid Films Consisting of Cubic Silsesquioxane-capped Polyurethane and Poly(3-hexylthiophene).

We fabricated stretchable and electric conductive hybrids consisting of polyhedral oligomeric silsesquioxane (POSS)-capped polyurethane (PUPOSS) and doped poly(3-hexylthiophene) (P3HT). In order to realize robust films coexisting polar conductive components in hydrophobic elastic matrices, we employed POSS introduced into the terminals of the polyurethane chains as a compatibilizer. Through the simple mixing and drop-casting with the chloroform solutions containing doped P3HT and polyurethane polymers, homogeneous hybrid films were obtained. From the conductivity and mechanical measurements, it was indicated that hybrid materials consisting of PUPOSS and doped P3HT showed high conductivity and stretchability even with a small content of doped P3HT. From the mechanical studies, it was proposed that POSS promoted aggregation of doped P3HT in the films, and ordered structures should be involved in the aggregates. Efficient carrier transfer could occur through the POSS-inducible ordered structures in the aggregates.

Measuring quantum coherence in bulk solids using dual phase-locked optical pulses.

Electronic and phonon coherence are usually measured in different ways because their time-scales are very different. In this paper we simultaneously measure the electronic and phonon coherence using the interference of the electron-phonon correlated states induced by two phase-locked optical pulses. Interferometric visibility showed that electronic coherence remained in a semiconducting GaAs crystal until ~40 fs; in contrast, electronic coherence disappeared within 10 fs in a semimetallic Bi crystal at room temperature, differing substantially from the long damping time of its phonon coherence, in the picosecond range.

Characterization of polymer structures based on Burnside's lemma.

Polymer structure modeling is a trend of recent material sciences. Developments of computational science and nanotechnology make it possible to predict properties of complicated molecular structures. Many theoretical and computational methods have succeeded in elucidating the nature of polymer structures. It is not always best to model whole complicated structures depending on computer capabilities. Significant properties of materials may be manifested in simple structural aspects. In the present study, characteristics of a polymer structure are investigated by applying Burnside's lemma to the modeling procedure. This method is expected to be available to model polymers or molecular crystals in which functional groups play an important role in expressing their functions. Every structure under the symmetry and periodicity is counted completely and the energy distribution caused by the conformations of functional groups can be clarified. The detailed procedure is introduced and the present method is applied to a problem for investigating molecular structures of sulfonated poly(ether ether ketone) (SPEEK). SPEEK is focused on a candidate for proton exchange membranes in polymer electrolyte fuel cells. Sulfonic groups have a significant role in proton exchange membranes to make proton conduction channels. From our analysis, it is found that sulfonic groups tend to be dispersed in SPEEK membranes at their stable conditions. These are unfavorable characteristics for proton exchange membranes due to their difficulty to form desirable water channels inevitable for the high proton conductivity. This is one reason why SPEEK membranes are inferior to Nafion® membranes that express the highest performance as proton exchange membranes. Using the present method, experimental and theoretical results previously reported are confirmed and detailed characteristics are discussed in terms of structural simplicities.