| 초록 |
The water sorption and diffusion behavior of PMDA-PDA and PMDA-ODA films, which were thermally imidized from the PAA and PAE precursor solutions, were investigated by the gravimetry and the stress relaxation analysis. In addition, the film morphology with the difference of backbone structure and precursor type was characterized by the X-ray diffraction and glass transition temperature. Regardless of measuring method, the water diffusion of polyimide thin films in this study were nearly Fickian and modified Fickian processes. For rigid rodlike PMDA-PDA, films prepared from PAE absorbs water more quickly than that from PAE precursor, whereas for semi-flexible PMDA-ODA, that from PAE absorbed water less quickly than the corresponding polyimide from PAA. This water sorption behavior might result from the morphological variations in the film, such as polymer chain order, intermolecular packing, microvoids, glass transition temperature, and precursor type.
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