Synthesis and Characterization of Hyperbranched Polymer Having Hole Transporting Ability

A hyperbranched polymer (HBP) was prepared by the condensation polymerization of 4-hydroxy-methylphenyldiphenylamine (TPA-CH 2 OH) and was compared with the corresponding linear polymer (LP) prepared by condensation polymerization of 4-methyltriphenylamine (MTPA) and formaldehyde (FA). It was found that the HBP had higher molecular weight with same molecular volume by using gel permeation chromatography (GPC) equipped with low angle laser light scattering (LALLS) and refractive index (RI) detectors. Electronic and optical properties of the two types of polymers were also examined. The two types of polymers showed almost same absorption in the UV-visible region, while HBP showed stronger emission than LP and a new excimer band at 470 nm. The cyclic voltammography showed that HBP had a redox peak around 1.22 V versus Ag/AgCl electrode, indicating that it has hole transporting ability. HBP is soluble in common organic solvents and forms good quality thin films. Their excellent morphological and thermal stability renders them advantageous for electroluminescence applications.