Synergistic Enhancement of PTFE Tribological Performance via LDH-Induced Adsorption and PEEK Support Framework

This study addresses the critical limitations of polytetrafluoroethylene (PTFE), including low mechanical strength and high wear rate (10–4 mm3/N·m), through a "rigid-flexible synergy" multiscale reinforcement strategy. Specifically, this study introduces a continuous spatial network particle structure coupled with layered lubrication, which incorporates polyetheretherketone (PEEK) and calcium–aluminum layered double hydroxide (LDH). LDH/PEEK/PTFE composites were fabricated via cold-press sintering, and their mechanical and tribological properties were systematically evaluated. The optimal performance was achieved at 20 wt % PEEK and 4 wt % LDH, where the compressive strength increased to 38.2 MPa (53% enhancement over pure PTFE), the friction coefficient decreased to 0.163 (10.4% reduction), and the wear rate reached 0.067 × 10–13 m3/Nm (94.1% reduction). Multiscale characterization (SEM/EDS/FTIR/XRD/Raman) and density functional theory (DFT) calculations revealed the underlying synergistic mechanisms: (1) PEEK disperses loads by forming a continuous spatial network particle structure, inhibiting plastic deformation and crack propagation of the matrix (24% increase in Shore hardness); (2) LDH nanosheets generated shear-aligned lubricating films with enhanced transfer film stability via strong interfacial adsorption (−0.61 eV, DFT); (3) PEEK-LDH interactions promoted tribochemical reactions, yielding carboxylate metal chelates (FTIR peak at 1430 cm–1) for optimized interfacial bonding. This work establishes the theoretical and technical foundations for advanced self-lubricating composites, demonstrating their potential in aerospace seals and heavy-duty bearings.