Theoretical and experimental studies of chiral polyurethanes

The theoretical and experimental design strategies of chiral polyurethanes with good second harmonic generation efficiencies are discussed. The noncentrosymmetry of the polymers was broken by means of chiral and chemical poling. Different varieties of main chain chiral polymers are obtained by varying the composition of chiral and amido diol monomers using DBTDL catalyst. The designed chiral polymer architecture gives rise to high molecular weight polymers by the polyaddition polymerization with good thermal stability, linear and nonlinear optical activity. The polymer with isomannide as chiral moiety and CED (obtained by the aminolysis of ε-Caprolactone with 1, 2 diamino ethane) as amido diol monomer is found to possess high second harmonic generation efficiency. Both theoretical and experimental studies based on second order nonlinearity indicated that the designed chiral polyurethanes are useful for various nonlinear optical applications.