Synthesis of Linear and Star-Shaped Poly[4-(diphenylamino)benzyl methacrylate]s by Group Transfer Polymerization and Their Electrical Memory Device Applications

Abstract

Hole-transporting triphenylamine (TPA)-based polymers, the linear poly[4-(diphenylamino)benzyl methacrylate] (PTPMA) and the three-armed star-shaped poly[4-(diphenylamino)benzyl methacrylate] (N(PTPMA)3), have been synthesized by group transfer polymerization (GTP). For the synthesis of N(PTPMA)3, the core-first approach coupled with the GTP was adopted using a newly designed silyl ketene acetal initiator with three initiating points. The polymerization results showed that the polymer molecular weights were precisely controlled by the monomer/initiator ratio. The new hole-transporting TPA-based polymers could be blended with electron-accepting [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) for electrical memory device applications. The experimental results showed that pristine PTPMA and N(PTPMA)3 exhibited dynamic-random-access-memory (DRAM) volatile electrical behavior, but their PCBM composite-based devices changed to the write-once-read-many times (WORM) nonvolatile memory characteristic or conducto...