Polystyrene thin films with incorporated borane clusters for electronic applications investigated by infrared reflection-absorption spectroscopy

Abstract

The paper is focused on the investigation of thin polystyrene (PS) films and PS films with incorporated anti-octadecaborane( 22) (anti-B18H22) clusters (PS+B18H22) with a thickness of 450 nm and 290 nm, respectively. The main aim is to describe the vibrational behavior of thin films in dependence on temperature and determine the changes connected with the glass transition of PS. Infrared reflection-absorption spectra were measured and from the plot of spectral region area (Arange) vs. temperature, glass transition temperature (Tg) of PS was extracted. The abrupt change in the course of A of Car-H stretching vs. temperature was assigned to the glass transition. Tg of PS and PS+B18H22 thin film was determined to be 74 °C and 77 °C, respectively. On the other hand, only a continuous decrease of A of C-H stretching vs. temperature was found for both samples indicating that each vibrational motion reacts uniquely on temperature increase. It was further found that anti-B18H22 is not fixed firmly in the thin layer at higher temperatures, because no B-H spectral response was detected above 91 °C. This result was also supported with TGA and DSC analysis showing a particular mass decrease at temperature 75 °C.