Soluble Polyimides Based on Diaminobenzoic Acid Alkylester

Shiki

2016

Self Cite

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.

Section: Introductionmentioning

confidence: 99%

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

Shiki

2016

Self Cite

Section: Introductionmentioning

confidence: 99%

Surface Wettability Controllable Polyimides Having Unsaturated Long-chain Alkyl Groups

Shiki

2015

Self Cite

Novel diamine monomers having unsaturated long-chain alkyl group (Oleoyl-DA) and saturated long-chain alkyl group (Stearoyl-DA) were synthesized from dibromo benzoic acid. The novel polyimides and copolyimides were synthesized from 3,4'-ODPA as a dianhydride, above diamines having unsaturated long-chain alkyl group or saturated long-chain alkyl group, and DDE as a diamine co-monomer by two step polymerization systems. The thin films of obtained polyimides were irradiated by UV light (λmax; 254 nm), and the contact angles for the water decreased from near 90° (hydrophobicity) to minimum 30° (hydrophilicity) in proportion to irradiated UV light energy. 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 oxidation of double bond in the unsaturated long-chain alkyl group significantly affect the changes of wettability by UV light irradiation based on the various analyses.

Section: Introductionmentioning

confidence: 99%

“…The polyimides were obtained by chemical imidization at 120˚C in the presence of pyridine as a base catalyst and acetic anhydride as a dehydrating reagent. The experimental details are described in the previous papers [3][4][5][6][7][8][9][12][13][14][15][16]. Polyimide thin films were obtained as follows: 0.5-2.0 wt % polyimide solution in NMP added a specified quantity of catalyst were drop-casted on glass substrates and the solution were slowly evaporated by heating at approximately 100-120 o C until the films were dried, then the films were dried in a vacuum oven at 100 o C for 12 h. Water contact angles were measured by SImage mini (Excimer.…”

Section: Introductionmentioning

confidence: 99%

Effect of Photoacid Generator on Surface Wettability Controllable Polyimides by UV Light Irradiation

Tahira

Shinohara

et al. 2015

Self Cite

The authors have systematically investigated the surface wettability controllable polyimides by UV light irradiation using the polyimides having long-chain alkyl or bulky alkyl groups on their side chains. In this paper, the effects of the addition of photoacid generator or photobase generator were examined. As a result of examining the UV light irradiation (λmax; 254 nm) onto the polyimides based on the diamine monomer having long-chain alkyloxy groups and phenyl ester linkage (12G1-AG-terphenyl diamine), it was proven that the addition of the photoacid generator was effective for the surface wettability control from hydrophobicity to hydrophilicity. On the other hand, the addition of photobase generator was not effective. Therefore, it is speculated that the photoreaction activated by the acid catalyst such as an acid catalyzed ether cleavage and acid catalyzed photo-Fries rearrangement enhance the generation of hydrophilic groups such as hydroxyl groups after UV light irradiation. In case that the suitable photoacid generator were selected, the surface wettability control of these polyimides by UV light irradiation (λmax; 365 nm) were accomplished. The utilization of the UV light (λmax; 365 nm) is the merit in the practical use. From the result of ATR analyses, it is recognized that the hydrophobic alkyl groups on the polyimide surface decrease and the hydrophilic groups such as hydroxyl groups generate on their surface.