Measurement of Capillary Pressure Curves in GDLs at Elevated Temperatures

摘要

An experimental setup has been developed to measure air-water capillary pressure curves for gas diffusion layers (GDLs) used in polymer electrolyte membrane fuel cells at elevated temperatures. Experiments were conducted at various temperatures from 25 to 85°C for Toray 120 with 0% and 10% PTFE. Notable shifts in the capillary behavior were seen and in some cases the shifts were of the same size as PTFE addition. In untreated samples the results suggest that GDL wettability changes with temperature once the temperature dependence of the surface tension has been accounted for. In treated samples, however, the wettability remains more or less constant with temperature. This behavior is in agreement with the temperature dependent values of water contact angle on PTFE and graphite.