Synthesis of low glass transition temperature worms comprising a poly(styrene-stat-n-butyl acrylate) core segment via polymerization-induced self-assembly in RAFT aqueous emulsion polymerization

Abstract

Nanodimensional polymeric worms (fibers) are of significant interest for a variety of potential applications. Herein, we have used polymerization-induced self-assembly (PISA) implemented as aqueous reversible addition–fragmentation chain transfer (RAFT) polymerization to synthesize worms comprising a corona of poly(acrylic acid-stat-poly(ethylene glycol) methyl ether acrylate) and a core of poly(styrene-stat-n-butyl acrylate). Worms with theoretical glass transition temperatures (T_g) of 27.1 °C and −37.6 °C were synthesized based on two different molar ratios of styrene : n-butyl acrylate (70 : 30 and 20 : 80) for the core segment (second block). To date, there is limited knowledge available on PISA synthesis of worms of low T_g. Light crosslinking of the core-segments was achieved by introduction of a small amount of divinyl monomer, ethylene glycol diacrylate or poly(ethylene glycol) diacrylate, during PISA at the beginning of polymerization or after 2 h of polymerization. Comparison of the crosslinking efficiency for ethylene glycol diacrylate and poly(ethylene glycol) diacrylate showed that the water solubility of the crosslinker plays an important role in regard to maintaining the worm morphology and obtaining satisfactory crosslinking.