title: An Alternative Approach to Evaluate the Wettability of Carbon Fiber Substrates.
abstract: The wettability of carbon fiber substrate plays an important role in a vast number of electrochemical energy production and storage technologies. Here, we report an alternative approach to evaluate the relative wettability for three substrates with the solid-liquid (S-L) interfacial area as the wettability parameter. We applied electrochemical techniques to quantify the S-L interfacial area and obtained the relative wettability on for three substrates with varying fiber morphology. This work proposes and validates a methodology to experimentally measure the substrate wettability and elucidates important aspects of the relevant wetting phenomena. Our results indicate that the wettability of carbon fiber substrate is affected by the liquid intrusion resulting from the instability of the Cassie-Baxter wetting state and that the contact angle is not dependent on the S-L interfacial area under the droplet. The present technique can be used to characterize the surface wettability of a wide range of conductive surfaces with irregular and multiscale surface roughness features.
authors.affiliation: Clean Energy Research Centre, The University of British Columbia , 6250 Applied Science Lane, Vancouver, British Columbia, Canada V6T 1Z4.
authors.forename: Pradeep Kumar
authors.initials: PK
authors.lastname: Sow
authors.affiliation: Clean Energy Research Centre, The University of British Columbia , 6250 Applied Science Lane, Vancouver, British Columbia, Canada V6T 1Z4.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Prass
authors.affiliation: Clean Energy Research Centre, The University of British Columbia , 6250 Applied Science Lane, Vancouver, British Columbia, Canada V6T 1Z4.
authors.forename: Walter
authors.initials: W
authors.lastname: Mérida
keywords: carbon fiber; contact angle; double layer capacitance; gas diffusion layer; wettability