Dielectric elastomers (DEs) have drawn much attention in artificial muscles and soft robotics, it’s still a big challenge to prepare DEs with high electromechanical performances. This article reports novel poly(thioether)-b-polysiloxane-b-poly(thioether) triblock copolymer based homogenous DEs with high electromechanical properties. (1) The triblock copolymer (PSiPGE) was synthesized through the ring-opening polymerization (ROP) of phenyl glycidyl ether (PGE) and carbonyl sulfide (COS) catalyzed by silicon alkoxides. The dipoles and the phase separation structure of this triblock copolymer enhanced the dipole polarizations and the interfacial polarizations between poly(thioether) and polysiloxane, thus improving the dielectric constant (ε', up to 5.8). In addition, the PSiPGE exhibited low elastic modulus (Y, 0.04MPa), and possessed high electromechanical sensitivity (β, ~145MPa-1) which is much higher than that of most reported homogenous DEs. (2) Based on the first section, another triblock copolymer (PSiFGE) was synthesized through the ROP of furfuryl glycidyl ether (FGE) and carbonyl sulfide (COS) catalyzed by silicon alkoxides, then the Diels-Alder (DA) reaction was achieved after the incorporation of bismaleimide (BMI), obtaining the thermo-reversible homogenous DE (PSiFGE-BMI). The introduction of DA bonds endowed the PSiFGE-BMI with thermo-reversible crosslinking network and tunable crosslinking degree. The resultant material exhibits alterable mechanical strength (varied from 0.16 MPa to 11.2 MPa) and elastic modulus (Y, from 0.6 MPa to about 79 MPa). Of significance, the PSiFGE-BMI possesses high ε' (up to 7.6) and high electromechanical sensitivity (β, up to 11.8 MPa-1). In addition, the homogenous DE exhibits excellent shape memory and shape reconfiguration behavior with the fixing ratio (Rf) and recovery ratio (Rr) of above 90%. This work provides a new strategy to construct homogenous DEs with excellent electromechanical performances, leading to a greater application aspect in the actuated devices.

Novel homogenous dielectric elastomer (DE) based on poly(thioether)-b-polysiloxane-b-poly(thioether) triblock copolymer with improved dielectric performance

ACS Spring 2022

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