Abstract
Fluorinated block copolymers containing imide and 1,3,4-oxadiazole rings were prepared in two steps. In the first step a bis(amino)aryl-ether-1,3,4-oxadiazole oligomer was prepared via a nucleophilic substitution reaction. The molecular weight of the oligomer was 7000 g/mol, as determined by 1H NMR spectroscopy. In the second step the oligomer was co-reacted with an aromatic diamine, namely 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and a fluorinated diacid chloride containing preformed imide rings. The resulted block copolymers were easily soluble in organic solvents such as N-methylpyrrolidone and some of them could be cast from solution into thin flexible films having good mechanical properties. They showed high thermal stability with decomposition temperature being above 440°C. Multiphase morphologies were observed irrespective of the concentration of the oligomer in the block copolymer. Electrical insulating properties of a copolymer were evaluated on the basis of dielectric constant and dielectric loss and their variation with frequency and temperature. Keywords: fluorinated block copolymers, thermal stability, thin films, dielectric constant