Wettability modification and region optimization of PEMCs porous transport layer: A comparative study utilizing PDMS and MTMS/HDTMS hybrid solutions

The gas-liquid transport efficiency of porous transport layers (PTLs) in proton exchange membrane electrolyzers (PEMECs) critically influences overall electrolysis performance. Wettability optimization enhances gas-liquid dynamics, and templated modification techniques are used to regulate hydrophilic/hydrophobic properties of PTL, improving gas-liquid distribution and transport pathways. This study investigates the influences of modifier composition and template patterns on the gas-liquid transport behavior electrolytic efficiency of PEMECs. Results showed that compared to polydimethylsiloxane (PDMS)-based systems, a methyltrimethylsilane (MTMS)/hexadecyltrimethoxysilane (HDTMS) composite formed superhydrophobic coating (contact angle θ = 150.3°) on titanium substrates, demonstrating superior interfacial stability and anti-wetting properties. Furthermore, by changing the wettability modification strategy, the effects of hydrophilic region proportions (10 %, 20 %, 30 %) and geometries on electrochemical performance were evaluated. It was shown that the 10 % hydrophobic sample achieved optimal results, with a minimum electrochemical resistance ( R ohm ) of 0.20497 Ω cm 2 at 1.7 V and 0.5 A/cm 2 . Additional experiments on hydrophobic region geometry revealed that circular designs enhance gas-liquid mass transfer by accelerating bubble detachment. These findings advance PTL optimization strategies and offer practical insights for improving PEMEC efficiency and scalability.