Axial Orientation of Co-Crystalline Phases of Poly(2,6-Dimethyl-1,4-Phenylene)Oxide Films

Films exhibiting co-crystalline (CC) phases between a polymer host and low-molecular-mass guest molecules are relevant for many applications. As is usual for semi-crystalline polymers, axially oriented films can give relevant information on the crystalline structure, both by Wide Angle X-ray diffraction fiber patterns and by polarized Fourier-transform infrared spectroscopy. Axially oriented CC phases of poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) with 1,3,5-trimethylbenzene (mesitylene) can be simply obtained by the stretching of CC PPO films. In fact, due to the plasticization effect of this highly boiling guest, PPO orientation can occur in a stretching temperature range (170–175 °C) nearly 50 °C lower than that generally needed for PPO films (220–230 °C). This low stretching temperature range allows avoidance of polymer oxidation, as well as formation of the mesomorphic dense γ PPO phase. Axially oriented CC phases of PPO with toluene, i.e., with a more volatile guest, can be instead obtained by the stretching (in the same low temperature range: 170–175 °C) of CC PPO blend films with polystyrene.

Vapor phase infiltration of zinc oxide into thin films of cis-polyisoprene rubber

Vapor phase infiltration (VPI) of ZnO into the elastomeric polymer polyisoprene creates an organic-inorganic hybrid material. Inorganic loading and hybrid structure depend upon the initial polymer free volume and the extent of polymer oxidation.

Influence of traces of oxidized polymer on the performances of bulk heterojunction solar cells

An innovative bottom-up approach was used to reveal the importance of traces of polymer oxidation products in altering solar cell efficiency.

Development of High Temperature Tantalum Polymer Capacitors

This paper focuses on the development of new 150°C capable surface mount polymer tantalum capacitors and the enabling technologies. The conductivity stability of the conducting polymers at high temperatures as well as the equivalent series resistance (ESR) stability of the polymer tantalum capacitors at these temperatures were investigated in this study. Analysis of the oxygen permeation paths causing polymer oxidation and materials solutions for preventing oxygen permeation and polymer oxidation are described. The development of new cathode and protective coating material technology is presented. Their effectiveness in providing high temperature ESR stability is demonstrated by high temperature life test at 150°C of polymer capacitors.