Plastron lifetime of superhydrophobic surfaces submerged in biofluids (poster)

Superhydrophobic surfaces find applications in numerous biomedical scenarios
requiring the repulsion of biofluids, biomolecules, and cells. Plastron, an entrapped air film on a superhydrophobic surface submerged in liquid, plays a pivotal role in this repellence. A key challenge is that the sometimes-limited plastron lifetime, which is the time that the fluid spends in contact with the air-solid composite interface before the air is lost and the fluid is then in contact with only a solid. Here we study the plastron lifetime of superhydrophobic surfaces immersed in several types of biofluids (protein solutions, cell media). We found that biofluids of all types had a shorter plastron lifetimes compared to pure water, and this is attributed to their lower surface tension and to biomolecule adsorption through hydrophobic-hydrophobic interactions. Proteins
(albumin and fibronectin) and glucose were found to be the major contributors to
plastron dissipation. We also studied the plastron lifetime of different
superhydrophobic surfaces that vary in terms of texture, feature size, solid fraction, structure height, and surface chemistry. The key findings are that longer term plastron stability and biofluid repellency benefits from a large plastron volume, a higher degree of surface roughness and Cassie solid fraction and smaller size scale.