Fluorinated aromatic polyimides as high-performance electret materials.

In view of the increasing significance of technology-driven devices such as microelectromechanical systems, energy-harvesting devices, and organic field effect transistors, polymer electret materials with durable electret performance at elevated temperatures become more and more important. However, typical polymer electret materials lose their performance at elevated temperatures. To provide polymer materials with improved electret performance over a broad temperature range, a series of aromatic polyimides with different degree of fluorosubstitution is presented.

Fast diffusion-limited lyotropic phase transitions studied in situ using continuous flow microfluidics/microfocus-SAXS.

Fast concentration-induced diffusion-limited lyotropic phase transitions can be studied in situ with millisecond time resolution using continuous flow microfluidics in combination with microfocus small-angle X-ray scattering. The method was applied to follow a classical self-assembly sequence where amphiphiles assemble into micelles, which subsequently assemble into an ordered lattice via a disorder/order transition. As a model system we selected the self-assembly of an amphiphilic block copolymer induced by the addition of a nonsolvent.