Bio-Based Cellulose-Supported Photocatalyst Enabling Reversible Complexation-Mediated Polymerization via Energy Transfer under White LED Irradiation

Abstract

Heterogeneous photocatalytic polymerization has emerged as a promising strategy for developing greener reversible complexation-mediated polymerization (RCMP) systems. In this study, a bio-based heterogeneous photocatalyst was prepared by anchoring betaine onto hydroxyethyl cellulose via esterification, aiming to address the drawbacks of homogeneous photo-RCMP systems and inorganic support catalysts, and thereby enabling photoinduced RCMP under white LED irradiation. This system enabled the synthesis of well-defined polymethacrylates with controlled molecular weights and narrow dispersity (Đ < 1.2). Upon light exposure, photoinduced energy transfer from the catalyst to alkyl iodide initiators promoted carbon-iodine bond cleavage, generating radicals to initiate polymerization. Density functional theory calculations revealed that electrostatic interactions between the iodide anion and the quaternary ammonium cation, together with halogen bonding between the catalyst and alkyl iodide, significantly lower the bond dissociation energy, thereby enhancing polymerization efficiency. Kinetic studies and light on/off experiments confirmed good temporal control, while chain-extension experiments demonstrated high chain-end fidelity. Furthermore, the photocatalyst exhibited broad monomer compatibility, retained over 90% of its activity after three recycling cycles, and performed effectively under natural sunlight. Overall, this work provides a sustainable and recyclable strategy for visible-light-induced RCMP by integrating renewable materials with efficient photocatalytic functionality.