Electrospun PVDF/CNT nanofiber membranes with synergistic optimization of tribological and piezoelectric properties for artificial joint implant coatings

Polyvinylidene fluoride (PVDF) is a piezoelectric polymer with outstanding flexibility, mechanical strength, and biocompatibility. α-phase PVDF exhibits excellent tribological properties, while β-phase PVDF is known for its superior piezoelectric performance. To achieve a synergistic optimization of both properties, PVDF must be effectively modified. In this study, electrospinning was employed to fabricate PVDF nanofiber membranes, with carbon nanotubes (CNT) incorporation serving as a structural regulator to balance the α-phase and β-phase content. As a result, the coefficient of friction (COF) was reduced by 14.4 % compared to pure PVDF, and the negative surface potential was mitigated, leading to a more uniform and stable distribution. The dual enhancement significantly improved both tribological and piezoelectric performance. CNT leads to an increase in the stability of the friction acoustic signal, reflecting the lubrication synergy effect of the composite system. The presence of CNTs greatly improved the wettability of the membrane, achieving a stable simulated body fluid (SBF) contact angle of just 29.07°. The modified PVDF/CNT membrane also demonstrated enhanced Ca²⁺ adsorption capability, maintaining excellent retention even after frictional wear, facilitating the formation of a stable bio-lubrication layer. The combined enhancements in lubrication, durability, and biocompatibility highlight the great potential of PVDF/CNT nanofiber membranes as advanced biomaterial coatings for next-generation artificial joint implants.