Water-sorption behavior of P-phenylene diamine–based polyimide thin films

✍ Scribed by Jongchul Seo; Anna Lee; Choonkeun Lee; Haksoo Han

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 187 KB
• Volume: 76
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(20000523)76:8<1315::aid-app12>3.0.co;2-4

✦ Synopsis

Four different p-PDA-based polyimide thin films were prepared from their respective poly(amic acid)s through thermal imidization at 400°C: poly(p-phenylene pyromellitimide) (PMDA-PDA); poly(p-phenylene biphenyltetra carboximide) (BPDA-PDA); poly(p-phenylene 3,3Ј,4,4Ј-oxydiphthalimide) (ODPA-PDA); and poly(p-phenylene 4,4Ј-hexafluoroisopropylidene diphthalimide) (6FDA-PDA). Water-sorption behaviors of polyimide films were gravimetrically investigated at 25°C and 22-100% relative humidity by using the modified electromicrobalance (Thin Film Diffusion Analyzer). The diffusion coefficients of water for the polyimides varies in the range of 1.6 to 10.5 ϫ 10 Ϫ10 cm 2 /s, and are in the increasing order: BPDA-PDA Ͻ PMDA-PDA ϳ ODPA-PDA Ͻ 6FDA-PDA. The water uptakes of polyimides vary from 1.46 to 5.80 wt %, and are in the increasing order: BPDA-PDA Ͻ ODPA-PDA Ͻ 6FDA-PDA Ͻ PMDA-PDA. The water-sorption behaviors for the p-PDA-based polyimides are closely related to the morphological structure; specifically, the diffusion coefficients in p-PDA-based polyimide thin films are closely related to the in-plane orientation and mean intermolecular distance, whereas the water uptakes are affected by the packing order.