Spatially Decoupled Donor and Acceptor Gradient Brush Particle Blends for Mechanically Robust, Fatigue-Resistant, and Recyclable Elastomers

Abstract Combining high mechanical strength, fatigue resistance, and reprocessability in a single soft material remains a fundamental challenge. Here, we report a strategy based on spatially decoupled interparticle hydrogen bonding in architecturally controlled brush particle blends. Complementary hydrogen-bonding motifs, namely poly(acrylic acid) (PAA) as donor and poly(dimethylaminoethyl methacrylate) (PDMAEMA) as acceptor, were incorporated into poly(n-butyl acrylate) (PnBA)-based gradient brush particles via surface-initiated atom transfer radical polymerization (SI-ATRP). Upon blending, reversible interparticle hydrogen bonds were formed, functioning as dynamic physical cross-links. The resulting materials exhibited tensile strengths up to 18 MPa, Young’s modulus of 95 MPa, and fracture strains exceeding 150–200%, a combination rarely achieved in physically cross-linked polymer networks. Hierarchical viscoelastic analysis revealed that the synergy between reversible interparticle bonding and architectural heterogeneity generates broad relaxation spectra and multiscale energy dissipation pathways. These features collectively underpin outstanding fatigue resistance, crack-propagation suppression, reprocessability, and thermally assisted self-healing, with annealing at 50 °C restoring approximately 90% of the original modulus and near-complete tensile strength. This work establishes spatial decoupling of hydrogen-bond donors and acceptors as a transferable design principle for durable, recyclable structural soft materials.