POLYIMIDE-POLYSILOXANE-SEGMENTED COPOLYMERS AS HIGH-TEMPERATURE POLYMER ELECTROLYTES

Based on the fact that the flexibility of the polymer backbone will af fect the ion transport and sometimes enhance the ionic conductivity, c opolymer electrolytes of 1,2,4,5-benzene-tetracarboxylic dianhydride ( PMDA), 4-aminophenyl ether (ODA), and aminopropyldimethyl-terminated p olydimethylsiloxane (PSX), with or without doping of lithium triflate, have been prepared and investigated by infrared spectroscopy and elec trical conductivity measurements. The PSX was found to be incorporated into PMDA-ODA polyimide to form block copolymers, and the best conduc tivity (10(-7) s/cm at 300-degrees-C) is observed in the lithium trifl ate-doped PMDA-ODA-PSX copolymer with a composition of 4PMDA : 3DA : 0 .6PSX : 2LiCF3SO3. This conductivity is about 100 times better than th e result of the lithium-doped PMDA, ODA, and 2,5-diaminobenzene sulfon ic acid (DABSA) copolymer (4PMDA: 3DA: 1DABSA: 1LiCF3SO3) recently rep orted by this group. (c) 1994 John Wiley & Sons, Inc.