Development of Non-Fluorinated Superhydrophobic Polymer Coatings

The development of superhydrophobic and water-repellent surfaces has gained the scientific interest during the recent years. It is well accepted that in order this to be achieved, an appropriate chemistry in conjunction with a hierarchical roughness are necessary. In most cases, fluorinated polymers have been utilized to provide the desired hydrophobicity; however, these are the subject of various rules and regulations and their use should be reduced. In the present work, we develop superhydrophobic polymer nanocomposite coatings consisting of non-fluorinated polymers in the form of water-based silicone emulsions, that provide the required hydrophobicity, and spherical nanoparticles that provide the roughness. The coatings were deposited via dipping or spraying on different substrates like stainless steel, glass and polypropylene to evaluate their wide utilization. The wetting properties were evaluated via contact angle (CA) and contact angle hysteresis measurements and the morphology of the coated surfaces was examined using Scanning Electron Microscopy (SEM). The nanocomposites were optimized so as to achieve the desired wetting properties whereas the effects of post-deposition treatments like annealing and spraying with different water solutions were investigated. For the optimized nanocoatings, superhydrophobic (CA > 150°) and water repellent (hysteresis < 5°) surfaces were obtained.