Monomer diffusion tendencies in complex-shaped materials by vapor deposition polymerization

Abstract

Conformal coatings are crucial for various applications. In this study, we investigate polyurea coatings on complex-shape polytetrafluoroethylene (PTFE) membranes using vapor deposition polymerization. The diffusion mechanism involves monomer adsorption and desorption on PTFE fibers, enhanced by an increased substrate temperature, facilitating monomer diffusion. A system pressure of 100 Pa promoted monomer collisions, forming oligomers with lower desorption rates, aiding polymer thin-film formation. The combination of high substrate temperature for diffusion and gas-phase oligomer formation resulted in uniform polyurea coatings across the PTFE membrane. A non-exhaustion method provided an extensive monomer diffusion, achieving a thorough polyurea deposition throughout the membrane structure.