Preparation of hydrophobic PTFE/ceramic membranes featuring a tight and uniform pore size distribution through the solid-state sintering of PTFE nanoparticles

The surface wettability and pore structure of membranes play crucial roles in determining their separation efficiency. Innovating ceramic membranes with hydrophobic surfaces holds considerable promise for broadening their applications. Owing to the remarkable hydrophobic properties and robustness of PTFE materials, this study suggests the fabrication of PTFE/ceramic composite membranes utilizing a solid-state sintering of PTFE nanoparticles. Polyvinyl alcohol (PVA) was employed as a binding agent to facilitate the formation of a uniform PTFE membrane layer on the porous ceramic substrate. A comprehensive investigation was conducted into the influence of various factors, including PVA addition, emulsion concentration, dip-coating duration, and sintering temperature, on the morphology and performance of these composite membranes. The results showed that the incorporation of PVA effectively mitigated the back-diffusion of PTFE particles and ensured the structural integrity of membrane. The resulting PTFE/ceramic membrane exhibited a finer and more uniform pore structure than the commercial PTFE membrane. The composite membrane boasted a water contact angle of 133°, an average pore size of 78 nm, and a membrane layer thickness of 3.8 μm. These characteristics contributed to its exceptional separation performance when utilized in the ultrafiltration of polystyrene nanoparticle suspensions and the androstenedione-contained water-in-oil emulsion.