Oil Repellent Evaluation Using Resonance Principle

The contact angle is measured when evaluating oil repellency in water in the static wettability of a solid. Basically, it is common to observe the shape of a solid water droplet, oil or solid interface with a camera or a telescope and evaluate it from an image. The phenomenon of wetting is whether liquid is likely to adhere to the solid surface or not, and is discussed in terms of the contact angle. Although this method can evaluate the wettability of the surface at an instant, it is difficult to evaluate when maintaining the state of wettability or when changing the environment. Therefore, we considered a method that can evaluate the condition while observing the progress of the wettability on the surface. For surface wettability, we report a new oil repellent evaluation method using the resonance principle. In the near future, this new evaluation method can contribute to dynamic wetness that incorporates the elements of time.