High electron mobility and tuneable glass transition temperature in fullerene-functionalized polynorbornenes

Abstract

Ring-opening metathesis polymerization is employed to copolymerize a C₆₀-functionalized norbornene monomer and its alkyl substituted analog, yielding a range of fullerene-grafted polynorbornene copolymers with varying fullerene-contents. High control over the comonomer built-in ratio is demonstrated and subsequently used to correlate thermal and electronical properties to the fullerene content of the copolymers. While previous works on fullerene-grafted polymers reported high glass transition temperatures and low electron mobilities, we show relatively low and controllable glass transition temperatures between T_g = 16.8 °C and T_g = 145.9 °C. Full suppression of fullerene crystallization is confirmed, while achieving outstanding bulk electron mobilities up to μ_e = 0.33 cm² V⁻¹ s⁻¹.