Achieving High Permittivity Paraelectric Behavior in liquid crystalline Mesogen-Free Sulfonylated comb-shaped polymers*

Ferroelectric liquid crystalline polymers (LCPs) stand at the forefront of innovations in advanced electronic and optoelectronic devices given the potential for high spontaneous polarization (P_s). Yet, most ferroelectric LCPs have low P_s, only around 1 mC/m². In this work, we introduced mesogen-free comb-shaped LCPs with strongly dipolar sulfonyl groups in side-chains to enhance dipole moment/dipole density and induce ferroelectric switching. By placing the sulfonyl groups away from the polyether main chain and adding methyl-branched alkyl side chains, we reduced the crystallizability and promoted formation of Smectic LC phase. Remarkably, these LCPs displayed paraelectric behavior with a high dielectric constant of 20−30. This study paves the way for designing mesogen-free LCPs with controllable dipole interactions to achieve ferroelectricity in future explorations.