Surface Wettability Controllable Polyimides Bearing t-Boc Group by UV Light Irradiation

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 90° (hydrophobicity) to minimum 60° (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.

Reversible Control of Surface Wettability of Polyimides Having Azobenzene Group on Their Side-chain by UV-Vis Light Irradiation

“…The authors also have investigated the surface wettability control of polyimides having various functional groups such as long-chain alkyl groups, t-Boc group, etc. by UV light irradiation [7][8][9][10][11][12][13][14][15][16][17]. However, these wettability changes are irreversible from the hydrophobicity to the hydrophilicity by UV light irradiation.…”

“…The polyimides having azobenzene group on their side chain were synthesized from 3,4'-ODPA or DSDA, as a tetracarboxycilic dianhydride and a novel functional diamine monomer, Azo-DA. Two step polymerization systems including poly(amic acid)s synthesis and chemical imidization were performed as a same manner as previously reported [7][8][9][10][11][12][13][14][15][16][17]. The chemical structures of obtained polyimides are shown in Fig.…”

Surface Wettability Controllable Polyimides Bearing Long-chain Alkyl Groups by UV Light Irradiation

“…These are the optimized synthetic conditions previously developed for the synthesis of soluble polyimides in our laboratory [3][4][5][6][7][8][9][10][11][12][13][14][15]19,20]. If the polyimides were insoluble in the polymerization solvent, NMP, gelation or precipitation happened in the course of imidization process.…”

“…The authors also have investigated the surface wettability control of polyimides bearing long-chain alkyl groups by UV light irradiation [5][6][7][8][9][10][11][12][13][14][15]. The incorporation of longchain alkyl groups in polyimide backbones has been performed by using the various diamine monomers having long-chain alkyl groups.…”

Surface Wettability Controllable Polyimides Having Various Functional Groups by UV Light Irradiation

“…Various approaches such as the use of repellent pore-structured polyimide films [5], the surface energy controlled ink-jet printing with UV irradiation [6], have been investigated to obtain the fine patterning. Recently, the authors also have investigated the surface wettability control of polyimides having hydrophobic groups such as long-chain alkyl groups by UV light irradiation [7][8][9][10][11][12][13][14][15][16][17]. The basic concept of these surface wettability controllable polyimides is shown in Fig.…”