Polyimide–Organosilicate Hybrids with Improved Thermal and Optical Properties

Through hydrolysis and polycondensation of amino-silane with alkyl bridged silane, a new type of polysilsesquioxane (PSSQ) was obtained. Here we use amine functionalized silane and bis­(silyl)­ethane to synthesize alkyl chain linked PSSQ. Compared to conventional polyhedral oligomeric silsesquioxane (POSS), this new silane compound has both enhanced thermal stability and improved compatibility with poly­(amic acid). Gelation of this silane compound with poly­(amic acid) provides polyimide–organosilicate composite materials. We show that films made from solutions of the composites exhibit higher optical transparency and superior dimensional stability during thermal treatment than films of pure polyimide or of polyimide composites with conventional POSS. Bridging of POSS and chemical bonding between POSS and polyimide chains significantly enhance the physical properties. These results provide useful information for designing molecular architecture for the fabrication of high-performance plastic substrates in the future display devices

Rapid oxygen diffusive lithium-oxygen batteries using a restacking-inhibited, free-standing graphene cathode film

© The Royal Society of Chemistry. A graphene-based porous electrode for a lithium-oxygen (Li-O 2 ) battery is investigated for use in next generation energy storage systems. The porosity of the cathode electrode in Li-O 2 batteries is a key factor in increasing their oxygen diffusion rate and electrochemical activity, and enables a longer cycle life. In addition, the adsorption behavior of the electrolyte is an important factor for the charging process and diffusion of oxygen. We report the fabrication of a restacking-inhibited film cathode using corrugated and highly porous reduced graphene flakes that have an outstanding capacity and cycle life. We have demonstrated a robust porous cathode film for the next generation Li-O 2 batteries, which provides (1) rich voids and spaces for oxygen-related reactions, (2) easy accessibility to the electrolyte and rapid oxygen diffusion. This study can be applied for the design of new solution-processed graphene and the development of Li-O 2 battery cathode