Toward high molecular weight triphenylamine-based hyperbranched polymers

Two kinds of triphenylamine-containing AB(2) monomers carrying or not carrying flexible alkyl chains were synthesized and fully characterized. One-pot Suzuki polycondensation (SPC) was applied to polymerize these monomers to prepare hyperbranched polymers. Hyperbranched polymers from AB(2) monomer not carrying alkyl chains exhibited poor solubility in common organic solvents such as THF, chloroform, toluene, etc. The poor solubility of the hyperbranched polymers hampered their applications and the further modification of the end groups. The introduction of difunctional core molecules, such as 9,9-dioctylfluorene and 9,9-dioctylfluorene trimer, in the polymerization process controlled the molecular weight and forced the hyperbranched copolymers soluble in common organic solvents mentioned above, but high molecular weight polymers could not be obtained. SPC of the AB2 monomers carrying flexible alkyl chains afforded high molecular weight fluorene-triphenylamine (F-TPA) alternating hyperbranched copolymers, which are fully soluble in common organic solvents, and their peripheral bromo functional groups can be further modified. The structures of the hyperbranched polymers were fully characterized by NMR, GPC, and combustion analysis. Initial studies on the thermal and the optical properties of the hyperbranched polymers were also reported.