Friction coefficient between a hydrophobic soft solid surface and a fluid: Determined by QCM-D

Quartz crystal microbalance with dissipation (QCM-D) response data was used to determine the friction coefficient (μ) between soft solid surface and ethanol. A self-assembly of Dodecanethiol (DCT) film on gold was carried out. The number of DCT grafted (Γ) onto gold surface was investigated at concentrated solutions (10–33% v/v). Such large concentration leads to an increase on grafting density, viscosity, roughness and water contact angle favoring the reduction of friction coefficient (∼0.0922). These results allow proposing a soft self-assembled hydrophobic film to reduce friction between fluids into conduit, tube, or some other device.