Study of related poly(1,3,4-oxadiazole-amide)s containing silicon or hexafluoroisopropylidene groups in the main chain

Two series of related poly(oxadiazole-amide)s have been synthesized by solution polycondensation reaction of aromatic diamines containing preformed 1,3,4-oxadiazole rings with diacid chlorides having silicon or hexafluoroisopropylidene groups. All these polymers were soluble in polar amidic solvents, such as N-methylpyrrolidinone and dimethylformamide and gave thin transparent free-standing films on casting their solutions. The polymers exhibited high thermal stability, with the initial decomposition temperature being above 400 degreesC. Most of these polymers did show a glass transition, being in the temperature range of 238-275 degreesC. Very thin coatings, in the range of tens of nanometres, which were deposited onto silicon wafers exhibited smooth and pinhole-free surfaces in atomic force microscopy investigations. The study of photoluminescence properties revealed that some of these compounds emit blue light, in the range of 440-475 nm. All these characteristics are discussed and compared with those of conventional aromatic poly(1,3,4-oxadiazole)s.