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.

Active Control over the Wettability from Superhydrophobic to Superhydrophilic by Electrochemically Altering the Oxidation State in a Low Voltage Range

“…In order to track the changes in surface wettability in response to alteration of the oxidation state, a reduction potential was applied on the substrate (working electrode) while simultaneously evaluating the CA (Figure S2, Supporting Information). The experimental setup design is similar to the capacitive wettability evaluation setup which can be found in our earlier works . The as‐deposited surface was used as the working electrode with two platinum wires as the counter and reference electrode ( Figure a).…”

“…Contact Angle Measurement and Electrochemical Alteration of Wettability : The static water CA measurement and the electrochemical alteration of a droplet placed on the substrate were done in a modified sessile droplet setup with electrochemical assembly, as shown in Figure S2 in the Supporting Information and described elsewhere . The electrolyte solution consisting of 0.1 m Na 2 SO 4 solution prepared in Millipore water was used in all experiments.…”

Assessment and Interpretation of Surface Wettability Based on Sessile Droplet Contact Angle Measurement: Challenges and Opportunities

“…The mechanism of charge separation at the interface of conductive materials arising from the double layer charging process can be formalized as a means for evaluating the solid–liquid interfacial interactions, as depicted in Figure . Several studies have illustrated the electrochemical assessment of wettability by exploiting the phenomenon of electric double layer (DL) formation at the electrode‐electrolyte interface . The rationale of using the DL capacitance as wettability metric stems from the fundamental wettability definition that is founded on the affinity between the solid and liquid phases.…”

Effect of thermally deposited siloxane‐methacrylate coating on bonding to glass fibre posts

“…The alterations of fibre posts promoted by the evaluated treatments can also affect the contact angles formed by water and the adhesive with the post surface. Generally, the contact angle arises from surface topography, surface chemistry and the heterogeneity of the material of the interface under the droplet; certain domains on a solid surface act as barriers that hinder the motion of the contact line of a liquid droplet (Sow et al 2015). Thus, hydrophobic domains will impair the motion of the water front (Dorrer & Ruhe 2006).…”