Biobased Polymers Enable the Synergistic Tuning of Li ⁺ Transport and Mechanical Robustness via Structural Design

As an eco-friendly alternative to traditional petroleum-based polymers, biobased ion-conductive polymers derived from unsaturated biomass acids exhibit tremendous potential. In this work, all-atom molecular dynamics (MD) simulations were employed to investigate the structure–property relationships of ferulate-based ion-conductive polymers. The systems were constructed from polymer chains randomly copolymerized by ferulic acid, 2-hydroxyethyl acrylate, and ethylene units, incorporated with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) at different mass fractions. Lithium ions (Li+) coordinate primarily with oxygen atoms from ester, carboxyl, and hydroxyl groups, maintaining stable local coordination despite lithium salt concentration (φ) variations. The study uncovers two conduction modes: direct Li+ hopping via decoupling from −COO–/–COOH groups and coupled conduction with −OH groups in polymer segments. Ionic conductivity exhibits a nonmonotonic trend, optimized via the synergy between carrier density and mobility. Mechanical properties of the systems were systematically characterized via diverse approaches including uniaxial tension, tension recovery, shear deformation, and fracture healing tests. After that, the MD data set was expanded with representative metrics including conductivity, tensile strength, viscoelasticity, and self-healing properties. Gaussian process regression (GPR) was implemented for predictive modeling, outlining parameter design directions to elevate both the electrical conductivity and mechanical performance. Multiobjective optimization maps the parameter space for peak performance, predicting an ionic conductivity of 6.13 × 10–4 S·cm–1 alongside a Young’s modulus of 104.1 MPa. This work establishes a data-driven design framework integrating MD with GPR to balance ionic transport and mechanical stability, paving the way for the development of biobased ion-conductive polymers in the field of intelligent flexibility.