Enhancing relative permittivity by incorporating PDMS-PEG multiblock copolymers in binary polymer blends

Polydimethylsiloxane (PDMS) elastomers are well-known to be soft and highly stretchable, yet they never achieve maximum elongation when utilised as dielectric elastomers, simply because their dielectric permittivity remains rather low. Conversely, polyethyleneglycols (PEG) are not stretchable, but they do possess high permittivity. Combining two such polymers in a block copolymer allows for further crosslinking and presents the possibility of substantial improvements in the actuation response of the resulting dielectric elastomer – if carefully designed. The objective is to synthesise a PDMS-PEG multiblockcopolymer, assembling it into discontinuous morphologies in PEG in a continuous PDMS network. PDMS-PEG multiblock copolymers, however, have been shown to be conductive and thus not capable ofactuating. By incorporating conductive PDMS-PEG multiblock copolymers into a commercial PDMS elastomer, the discontinuity in PEG can be acquired and the relative permittivity (ε’) is significantly enhanced (60%) with 5wt% of PDMS-PEG block copolymer incorporated into the silicone elastomer.