A Modeling for Contact Angle and Wetting Effect in Nano-Layers

摘要

This study can be useful in designing and understanding the wetting effect in biomedical, biological, self-cleaning materials and.... Hydrophilia and hydrophobia are among attributes of substances and show the extent of water excretion or absorption on different surfaces. If a surface is prone to absorb water hydrophilic, and if it is susceptible to excrete water, it is called hydrophobic. Since the simplest way to distinguish Hydrophilia or hydrophobia of a surface is determining the contact angle of the drop with the surface, many attempts have been done to measure the contact angle and present models compatible with experimental observations. The present study, first, presents a brief explanation of Hydrophilia and hydrophobia concepts and discusses the model related to these issues; then, through combining physical phenomena, a new model, which is supposed to be free from the defects of the previous one and give stronger justification for physical observations, is given. The previous model, though reformed evolutionary, was flawed with the following inadequacies: taking the surface to be flat (Young equation), single material rough surface (Wenzel model), and composite rough surface or a combination of two substances (Cassie-Baxter model). In the rest of the evolutionary process, we present a model related to rough combination surface of N substances; in this case, the rough surface is taken to be a set of cavities which imprison air (Like Cassie-Baxter model).