ADHESION BEHAVIOR OF PDMS-CONTAINING POLYIMIDE TO GLASS

The effect of the incorporation of poly(dimethyl siloxane) (PDMS) segm ents into a poly[N,N'-(p,p'-oxydiphenylene) pyromellitimide] (PMDA-ODA ) polyimide backbone on the adhesion between PMDA-ODA polyimide and gl ass was investigated using X-ray photoelectron spectroscopy (XPS), inf rared (IR) spectroscopy, contact angle measurements, and the peel test . The peel energy of PMDA-ODA polyimide to glass was significantly imp roved when low molecular weight PDMS (248.5 g/mol) was incorporated, w hile little improvement was observed for the incorporation of high mol ecular weight PDMS (900 or 1680 g/mol). Exposure to air resulted in a considerable deterioration in the peel energy for the pure PMDA-ODA po lyimide, while no deterioration was observed for the PDMS-containing p olyimides. The improvement in peel strength was successfully achieved by the incorporation of very small quantities of PDMS such as 2 wt%. B ased on XPS, IR spectroscopy, and contact angle measurements, it is su ggested that the incorporated PDMS segments migrated from the bulk pol yimide to the polyimide/glass interface and chemically bonded to the g lass surface, which resulted in enhancement of the peel energy. Howeve r, a weak boundary layer was formed between the bulk polyimide and gla ss when a high molecular weight PDMS (900 or 1680 g/mol) was incorpora ted and thus the peel energy deteriorated.