Understanding Nanoscale Wetting using Dynamic Local Contact Angle Method

摘要

A multiscale quantum/classical-framework for hydrophobicity and UV absorption in heterogeneous coatings is presented. Atomistic water droplet simulations on coated oxide surface are used to define nanoscale contact-angles using a new numerical technique called the dynamic local contact angle (DLCA) method. The DLCA method is well suited to calculate macroscopic contact angles for polymeric and composite coatings. The accuracy of the method is tested for a series of common polymers and composites. In addition, the sensitivity of the contact angles towards functional groups and nanoscale roughness are tested using varying molecular structures. Fluorinated polyhedral oligomericsilsesquioxanes (F-POSS) molecular frameworks are used as a model system. Changes in contact angle and UV absorption spectrum as a function of hydrophobic chain length are calculated to test the feasibility of developing a virtual framework for new coating design connecting atomistic calculations to continuum level material properties.