Conjugated Polymers with Linear and Hyperbranched Structures and Advanced Materials Properties

Alkyne polymerizations are effected by tungsten- and tantalum-based catalysts, giving linear polyacetylenes(LPAs)and hyperbranched polyarylenes(HPAs)of high molecular weights(Mwup to 2.5 × 105)in high yields(up to 93%). All the LPAs and HPAs are thermally stable and completely soluble in common solvents such as THF, toluene, dichloromethane, and chloroform. Incorporation of biphenyl mesogenic pendants into poly(1-phenyl-1-hexyne)structure endows the LCPA with nematicity. Upon photoexcitation, the LPAs and HPAs emit strong UV and blue lights with high quantum yields(up to 94%). Multilayer electroluminescence devices of LPAs emit blue light with maximum luminance and external quantum efficiency of 1065 cd/m2and 0.86%, respectively. The HPAs attenuate strong laser pulses, with optical limiting performances comparable to that of C60, a well-known optical limiter.