Surface-fluorinated, sinter-free ceramic scaffold antifouling films by synergistic C-F3 and Al-O-F reconstruction

Abstract

The development of multifunctional antifouling films against extremely harsh environments should involve a specific material strategy that can comprehensively address critical challenges in chemical durability, mechanical resilience, and thermal stability. Herein, we present a surface-fluorinated ceramic nano-assembly approach to bridge the beneficial characteristics of poly(vinylidene fluoride) and ceramic nanoparticles. We designed a chemical scheme of synthesizing hollow SiO2 nanoparticles with a low density of 2.07 g cm− 3 (closely identical to the value of 1.8 g cm− 3 for poly(vinylidene fluoride)) and subsequently built the sinter-free, hollow SiO2 assemblies by introducing graphene oxide sheets as two-dimensional interfacial binders. A pH-controlled heterogeneous sol-gel reaction was also designed to deposit a chemically robust Al2O3 layer on top of cohesive ceramic frameworks. Then, we prepared highly uniform hybrid composites by promoting a strong electrostatic bonding between the positively charged PVDF-g-Q4VP (quaternary pyridinium-containing monomer-grafted poly(vinylidene-fluoride)) and the negatively charged low-density Al2O3 / hollow SiO2 assemblies. Post-thermal annealing induces a synergistic surface chemistry reconstruction that generates terminal CF3 and interfacial Al-O-F functional groups. Notably, the resulting surface-fluorinated ceramic scaffold films exhibit a low-surface energy property, with a contact angle as high as 145 °, along with a thermal tolerance of up to 450 ℃ and a mechanical hardness of 1.31 GPa, which have never been achieved in conventional fluorinated polymers. The films maintain a contact angle of over 140° after being exposed to 1.0 M hydrofluoric acid and pH 1.0 solutions, demonstrating the stability of their low-surface-energy characteristics under harsh chemical environments. It is believed that this combinatorial material design provides a scalable route for multifunctional antifouling films that are capable of thermal/chemical/mechanical stability while preserving structural integrity and superhydrophobicity.