Electron Beam-Induced Graft Copolymerization of Cellulose: Uncovering Interaction-Driven Mechanisms for Functional Films

Electron beam irradiation (EBI) enables the initiator-free graft copolymerization of cellulose, yet its underlying molecular mechanism remains poorly understood. Clarifying the intermolecular interactions and grafting behavior is critical to the rational design of high-performance cellulose-derived functional materials. Herein, cellulose-g-poly(sodium acrylate-co-acrylamide) copolymer films were fabricated via EBI-triggered in situ graft cross-linking of sodium acrylate (ANa) and acrylamide (AM) within the cellulose matrix. The effect of the monomer ratio on the grafting efficiency and macroscopic performance was systematically investigated. At the optimal ANa:AM molar ratio of 5:1, the films exhibited a high swelling ratio, favorable skin conformability, good biocompatibility, and excellent gel properties. Multiscale simulations combining Monte Carlo, molecular dynamics, and density functional theory were carried out to reveal the intrinsic grafting mechanism. The negative Gibbs free energy of mixing confirmed thermodynamically spontaneous mixing and superior compatibility between cellulose and grafted chains. Interaction analysis confirmed that electrostatic interactions serve as the dominant driving force, accompanied by hydrogen bonding and van der Waals forces, forming a robust synergistic network for structural stabilization and property enhancement. Overall, EBI-mediated graft copolymerization is governed by both radical initiation and favorable thermodynamic intermolecular interactions. This work provides insights into the interaction-driven mechanism of EBI-induced grafting and offers theoretical guidance for the development of high-value cellulose-based functional materials.