High mechanical properties and ionic conductivity of polysiloxane sulfonate via tuning ionization degree with clicking chemical reaction

Abstract

Despite excellent environmental adaptability and good optical transparency, polysiloxane was poor electron or ion conductors. In this paper, ionized polymethylvinylsiloxane (I-PMVS) had been prepared via coupling anionic ring-opening polymerization of 2, 4, 6, 8-tetravinyl-2, 4, 6, 8-tetramethyl-cyclo-tetrasiloxane with thiolene addition reaction of sodium 2-mercapto-ethanesulfonate (MESNA). The degree of ionization was precisely controlled by adjusting the grafting content of MESNA via clicking chemical reaction. FTIR, 1 H NMR, and XRD were used to investigate the composition and structure of I-PMVS. TGA and DSC was used to investigate the thermal properties. The increase of ionization degree reduced the crystallinity of the polymer and bulk cohesion, and increased the T g of I-PMVS and maintained good thermal stability. Meanwhile, the water contact angle (WCA) test showed that the increase of ionization degree improved the hydrophilicity of PMVS and the high degree of ionization made PMVS having excellent water-solubility. The test of tensile properties showed I-PMVS possessed good tensile strength without filler reinforcement. Electrochemical impedance spectra (EIS) indicated I-PMVS possessed a high ionic conductivity (σ), highest to 4.20 × 10 −6 S/cm when 100% grafting. Ionization of PMVS should provide a strategy to develop high performance of polyelectrolyte applied in the field of energy storage devices and bionic materials. • Ionized polysiloxane with adjustable number of ions was obtained via click reaction. • The physical properties were tuned via varying the grafting ratio of ion group. • Mechanical strength and ion conductivity were enhanced via increasing grafting ratio.