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 (M-w up to 2.5 x 10(5)) 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%). Multi-layer electroluminescence devices of LPAs emit blue light with maximum luminance and external quantum efficiency of 1065 cd/m(2) and 0.86%, respectively. The HPAs attenuate strong laser pulses, with optical limiting performances comparable to that of C-60, a well-known optical limiter.