Electroactive methacrylate-based triblock copolymer elastomer for actuator application

A series of ABA triblock copolymers of methyl methacrylate (MMA) and dodecyl methacrylate (DMA) [poly(MMA-b-DMA-b-MMA)] (PMDM) were synthesized by Ru-based sequential living radical polymerization. For this, DMA was first polymerized from a difunctional initiator, ethane-1,2-diyl bis(2-chloro-2- phenylacetate) with combination of RuCl₂(PPh₃)₃ catalyst and nBu₃N additive in toluene at 80 °C. As the conversion of DMA reached over about 90%, MMA was directly added into the reaction solution to give PMDM with controlled molecular weight (M _w/M_n ≤ 1.2). These triblock copolymers showed well-organized morphologies such as body centered cubic, hexagonal cylinder, and lamella structures both in bulk and in thin film by self-assembly phenomenon with different poly(methyl methacrylate) (PMMA) weight fractions. Obtained PMDMs with 20-40 wt % of the PMMA segments showed excellent electroactive actuation behaviors at relatively low voltages, which was much superior compared to conventional styrene-ethylene-butylene-styrene triblock copolymer systems due to its higher polarity derived from the methacrylate backbone and lower modulus. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 A series of well-defined MMA-DMA-MMA triblock copolymers with different molecular weights and compositions were synthesized by in situ sequential block copolymerization of DMA followed by MMA from a difunctional initiator through Ru-based living radical polymerization. Obtained triblock copolymers showed periodically well-organized morphologies both in bulk and in film states, giving excellent actuation performances at relatively lower electric fields due to their polar methacrylate groups (k), lower modulus, and microstructures.