Unraveling the Effects of Surface Functional Groups and Assembly Orientations on the Interfacial Mechanics of MXene/Silk Composites

Abstract

Interfacial regulation is the core and an urgent scientific issue for optimizing the performance of MXene-based biocomposites. This study innovatively and systematically investigates the coupling effects of Ti₃C₂Tₓ terminal groups (-O, -OH) and silk fibroin (SF) chain orientations (0°, 45°, 90°) on interfacial mechanical properties of MXene-based biocomposites. Equilibrium analysis demonstrates that the Ti₃C₂(OH)₂ terminal groups construct the strongest hydrogen bond network, yielding the maximum interfacial binding energy. Shear simulations reveal significant orientational differences in interfacial strength: the 0° orientation achieves the highest shear strength, confirming that ordered alignment is critical for efficient stress transfer. Dynamic analysis uncovers two distinct interfacial failure modes: the 0° orientation exhibits brittle fracture under high strength, while the 90° orientation undergoes ductile failure dominated by dynamic friction. The bulk structure of SF remains stable during tension, verifying that the reinforcement mechanism of MXene originates from optimized interfacial load transfer. This work provides crucial atomic-scale guidance for the rational design and optimization of interfacial mechanical properties in MXene-based composites.