High temperature polyimide thin films: The effect of photosensitive (DMAEM) precursor and different backbone structures on water sorption

Abstract

Three different polyimide films, BPDA-PDA, PMDA-ODA, and BTDA-ODA, were prepared from amic acid and photosensitive(DMAEM) precursors. The effect of backbone structures and precursors on the water sorption and the morphological structure in polyimide thin films was investigated. Gravimetric technique was employed to study the water sorption kinetics and wide angle x-ray diffraction (WAXD) technique for the morphological structure investigation of fully cured polyimide thin films. PMDA-ODA, BPDA-PDA and BTDA-ODA polyimide films prepared from amic acid precursor exhibited water diffusivities of 10.5 x 10(-10) cm(2)sec(-1), 1.4 x 10(-10) cm(2)sec(-1), and 10 x 10(-10) cm(2)sec(-1), respectively. For the linear BPDA-PDA polyimide, photosensitive(DMAEM) precursor distrupted the packing order in the microstructure. The disordered structure of polyimide thin film affected significantly the water sorption kinetics. The diffusivity of water in BPDA-PDA polyimide thin film prepared from photosensitive precursor was increased to 5.0 x 10(-10) cm(2)sec(-1). However, for the hinged PMDA-ODA and BTDA-ODA polyimide thin films prepared from photosensitive precursor no significant changes were observed in the morphological structure and water sorption kinetics.