Experimental Study of Drag Reduction on Superhydrophobic Surfaces Using Quartz Crystal Microbalance (QCM)

A durable superhydrophobic coating formulation with epoxy binder thermoset was used to coat on surfaces, which provide high quality for corrosion protection, reduced biofouling and improved hydrodynamic behavior. The single and double layers coating of these nanostructured epoxy were fabricated and coated on a novel quartz crystal microbalance (QCM) technique to investigate their hydrophobic properties. Different static and dynamic wettability were obtained and characterized by evaluating the electrical impedance of QCM coated with nanostructured epoxy in air and DI water. It was found that QCM is able to quantitatively characterize the hydrophobicity of these nanostructured polymer surfaces. For double layer coating, the frequency shift in DI water was smaller in comparison to the single layer one. The reduction in mechanical impedance of QCM clearly demonstrates the effect of enhanced hydrophobicity for both single and double layers. The experimental results show that the hydrophobic surface resulted in smaller mechanical impedance loading, while the hydrophilic surface exerted much larger mechanical impedance. The outcome of this research will build a solid foundation for the further improvement of vehicles coated with superhydrophobic surfaces operating in water and increased equipment life.