Abstract
Novel diamine monomers having tert-butoxycarbonyl (t-Boc) group were synthesized from the corresponding dinitro compounds by reductive reaction. The novel polyimides and copolyimides were synthesized from 3,4'-oxydiphthalic anhydride (3,4'-ODPA) as a tetracarboxylic dianhydride, above functional diamines having t-Boc group, and 3,5-diamino-N-tetradecylbenzamide (ADBA-14) as a diamine co-monomer by one-pot polymerization system using pyridine as a solvent. The thin films of obtained polyimides were irradiated by UV light (λmax; 365 nm), and the contact angles for the water decreased from near 90o (hydrophobicity) to minimum 60o (hydrophilicity) in proportion to irradiated UV light energy. The addition of photoacid generator (PAG) accelerated these changes of wettability. From the result of surface analyses such as ATR and XPS, it is recognized that the hydrophobic groups on the polyimide surface decrease and the hydrophilic groups such as hydroxyl groups and carboxyl groups generate on their surface. Furthermore, it is considered that the cleavage of t-Boc group significantly affect the changes of wettability by UV light irradiation based on the various analyses.
