Surface Wettability Controllable Polyimides Having Various Photoreactive Groups by Photo-irradiation

The soluble polyimides were synthesized from tetracarboxylic dianhydrides such as 3,4'-oxydiphthalic anhydride (3,4’-ODPA) and diamine monomers having various photoreactive groups, which are photo-oxidative groups, photoreaction groups based on photoresist technology, and photochromic groups. The thin films of obtained polyimides were irradiated by UV light (λ max; 254 nm or 365 nm), and the contact angles for the water decreased from near 100° (hydrophobicity) to minimum 20° (hydrophilicity) in proportion to irradiated UV light energy. The reversible wettability changes of the polyimides having photochromic groups by UV-Vis light irradiation were also investigated. Various surface analysis such as ATR, solid state refractive UV, XPS support above surface wettability changes of the polyimides.