One-pot synthesis of a new hyperbranched polyester containing 3,6-di-acceptor-substituted carbazole chromophores for nonlinear optics

The preparation of a new AB(2) monomer and a precursor of AB(2) monomer bearing carbazole chromophores is described. A new hyperbranched polymer containing carbazole substituted with two acceptor groups for nonlinear optical materials has been synthesized starting from the precursor of AB(2) monomer 3,6-diformyl-9-(11-hydroxyundecyl)carbazole via Knoevenagel condensation and ester exchange condensation in a one-pot reaction. This hyperbranched polymer with a mass-average molar mass of about 20000 g/mol is soluble in common organic solvents. The thin polymer films could be obtained from chloroform solution by spin coating. Differential scanning calorimetry analysis showed no crystalline transitions for this hyperbranched polymer and the glass transition temperature of the polymer is about 97,6 degrees C. The resulting thin and glassy polymer films were shown to exhibit reasonably second harmonic generation efficiencies (d(33) = 7 pm/V) after electric corona poling at about 100 degrees C.