Drag Reduction Through Hydrophobic Aerogel Film

A thin hydrophobic film was developed to allow for the reduction in drag experienced by vessels that use water as a their medium of mobility. Hydrophobicity in the films was achieved using silica aerogel prepared with the chemical methytrimethoxysilane (MTMS). To make the films, the aerogel was ball milled to powder form and mixed with polyvinyl butyral. The mixture was then placed in a specially designed mold and pressed using a hydraulic hot press. Initial films were non-uniform, crumbly, had average water contact angles of 145 degrees when drop shape analysis was conducted, and were only 3 inches by 3 inches. To improve the films, the procedure was altered to increase the amount of MTMS present in the aerogel, optimize the hot press settings and a better mold for pressing the films was designed. This resulted in a film that is smooth, uniform, and super-hydrophobic. The film has average contact angle of 158.3 degrees and can be easily bent. This presentation will focus on the methods used to prepare the films their resulting properties.