According to classical method polyimides were obtained in two-step polycondensation process via 10% solutions of poly(amic acid)s in dimethylformamide (DMF). Poly(amic acid)s were synthesized from chosen tetracarboxylic acids dianhydrides: pyromellitic (PMDA), 4,4'- (hexafluoroisopropylidene)diphthalic (6FDA), 4,4'- oxydiphthalic (ODPA) and aromatic diamines: 4,4'- oxydianiline (ODA), 1,4-phenylenediamine (PPD), 4,4'- ethylenedianiline (DAB), 4,4'-diaminodiphenylmethane (MDA), 4-methyl-1,3-phenylenediamine (MMPD) and 2,3,5,6- tetramethyl-1,4-phenylenediamine (DAD) in the first step of this reaction. The indium tin oxide (ITO)-glass plates or glass plates were spin-coated with the poly(amic acid)s solutions and dried. The polyimide layers were prepared by gradual heating in various temperatures (100 degree(s)C, 150 degree(s)C, 180 degree(s)C, 200 degree(s)C, 220 degree(s)C and 250 degree(s)C). The degree of imidization was estimated by means of IR spectroscopy. Obtained PI layers were mechanically modified by rubbing. Three various rubbing materials were used: cotton, silk and chamois leather. Surface free energy and its components of polymer layers were evaluated on the basis of their wet ability by standard liquids (diiodomethane, 1- bromonaphthalene, formamide, ethylene glycol, water). It was found that decrease of intensity of rubbing process yields to increase of contact angle for each of rubbing materials. Polyimide layers rubbed with chamois leather were characterized by the best wet ability. The rubbing process increase surface free energy of tested polyimide films.

Date Published: 27 June 2002
PDF: 4 pages
Proc. SPIE 4759, XIV Conference on Liquid Crystals: Chemistry, Physics, and Applications, (27 June 2002); doi: 10.1117/12.472160

Published in SPIE Proceedings Vol. 4759:
XIV Conference on Liquid Crystals: Chemistry, Physics, and Applications
Jolanta Rutkowska; Stanislaw J. Klosowicz; Jerzy Zielinski, Editor(s)