Fluorine-free strongly dipolar polymers exhibit tunable ferroelectricity

Current research on ferroelectric polymers centers predominantly on poly(vinylidene fluoride) (PVDF)–based fluoropolymers because of their superior performance. However, they are considered “forever chemicals” with environmental concerns. Here, we describe a family of rationally designed fluorine-free ferroelectric polymers, featuring a polyoxypropylene main chain and disulfonyl alkyl side chains with a C3 spacer: −SO₂CH₂CHRCH₂SO₂− (R = −H or −CH₃). Both experimental and simulation results demonstrate that strong dipole-dipole interactions between neighboring disulfonyl groups induce ferroelectric ordering in the condensed state, which can be tailored by changing the R group: ferroelectric for R = −H or relaxor ferroelectric for R = −CH₃. At low electric fields, the relaxor polymer exhibits electroactuation and electrocaloric performance comparable with those of state-of-the-art PVDF-based tetrapolymers.. Authors: Huang, Jiahao [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000193265320); Rui, Guanchun [Case Western Reserve Univ., Cleveland, OH (United States); Pennsylvania State Univ., University Park, PA (United States); Arkema, King of Prussia, PA (United States)] (ORCID:0000000240972205); Yan, Yueming [Vanderbilt Univ., Nashville, TN (United States)] (ORCID:0000000221580177); Allahyarov, Elshad [Heinrich-Heine Univ., Dusseldorf (Germany); Russian Academy of Sciences (RAS), Moscow (Russian Federation); Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000172124713); Kwok, Man-Hin [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000299382648). DOE Contract: FE0032273; SC0012704; SC0018075. Subjects: 36 MATERIALS SCIENCE