Perfluoropolyethers as superhydrophobizing agents for carbon-based surfaces of fuel cell gas diffusion layers

Perfluoropolyether (PFPE) peroxide confers superhydrophobic properties to carbon black (CB) and carbon cloth (CC) as Gas Diffusion Layer (GDL) materials by direct functionalization. The thermal decomposition of PFPE peroxide synthesizes PFPE radicals which covalently bond the unsaturated moieties on carbonaceous surfaces. PFPE-functionalized CB and CC were characterized by X-ray photoelectron spectroscopy (XPS), surface area analysis, resistivity measurements, scanning electron microscopy (SEM) and contact angle measurements. The PFPE-modified materials resulted superhydrophobic were employed for the fabrication of single and dual layer GDLs. GDLs were tested in a single fuel cell at the lab scale. The cell tests were run at two temperatures (60°C and 80°C) with a relative humidity (RH) of hydrogen and air feeding gases equal to 80/100% and 60/100%, respectively.