Enhanced Strength, Ductility, and Impact Resistance of Epoxy Resins by Deformable Liquid Metal Particles With Covalent and Non‐Covalent Interfacial Design

Liquid metal particles (LMPs) hold immense potential for advanced composites. However, achieving homogeneous dispersion and controlled interfacial bonding remains a critical challenge. By taking the dispersion of LMPs in an epoxy resin as a model system, we systematically regulated the interface via two simple and efficient modification strategies: covalent reactive anchoring (KH560) and non‐covalent steric shielding (BYK‐9076). The dispersion states of LMPs and mechanical properties of the EP composites were compared to elucidate how different interfacial architectures regulate particle dispersion, interfacial constraint, and the deformation accommodation. The two strategies produced distinctly different mechanical responses. Covalent interfacial coupling through KH560 favored stress transfer and resulted in a higher flexural modulus (2.42 GPa) and impact strength (14.95 kJ m −2 ), whereas the sterically stabilized BYK‐9076 interface produced the highest tensile strength (80.6 MPa) while maintaining a similarly high elongation at break. This work provides a comparative interfacial engineering framework for regulating the dispersion and mechanical responses of LMPs in polymer matrices, offering a useful basis for the mechanical design of LMP‐containing polymer composites.