Replacing ePTFE and ETFE: Low-Pressure PECVD Hydrophobic Coatings for Membranes and Composite Release Films

Presented by Nicolas Vandencasteele, Coating Plasma Innovation

This presentation introduces a versatile low-pressure PECVD surface-treatment process designed to enhance hydrophobicity and water entry pressure (WEP) across a wide range of membrane substrates. We investigate how plasma configuration—direct versus indirect PECVD—affects hydrophobic performance. Multiple precursor chemistries are evaluated to optimize water repellency, durability, and process scalability. The approach is applicable to membranes that are initially hydrophilic or hydrophobic and manufactured through diverse technologies. It enables the use of standard, PFAS-free membrane materials as potential alternatives to ePTFE. The same plasma polymerization platform is further demonstrated as a release coating for composite manufacturing films. Deposited at sub-5 nm thickness on polyamide and polyimide substrates, the coating imparts the low surface energy required for clean release from epoxy, polyester, and BMI resin systems, without release agent or mould wax. Thermal stability is demonstrated up to 390°C under 10 bar consolidation pressure, establishing compatibility with both standard thermoset and high-performance thermoplastic composite cure cycles. These results position plasma-deposited PFAS-free nanocoatings as a viable alternative to ETFE and FEP release films currently used in the composites industry.