Eco-friendly and Sustainable Materials and Processes for Producing Superhydrophobic Surfaces

Until now, superhydrophobicity has been successfully mimicked by scientists through careful observation and analysis of naturally occurring surfaces with this property. The main result is the distinct hierarchical scale texture found on water-repellent plant and insect surfaces. These textures also contain unusual waxy protrusions or structures that can readily trap air beneath water droplets. With modern nanofabrication, lithographic and wet chemistry techniques, scientists can replicate such surface textures and make them more complex. In doing so, many synthetic materials that have a very low affinity for water are used. Perfluorinated substances are among them but present some environmental issues. Additionally, the majority of superhydrophobic coating formulations and processing are thought to be either prohibitively expensive to implement into standard industrial practice or not environmentally friendly enough to support large-scale fabrication. However, recently significant efforts have been made to fabricate superhydrophobic coatings using natural materials and environmentally friendly methods that have a smaller potential environmental impact. This chapter introduces, evaluates and discusses such advances, comparing their effectiveness with that of conventional methods while recognizing the difficulties and emphasizing the need to devote more resources to the development of strong and durable superhydrophobic coatings resulting from clever processing of natural materials or synthetic biodegradables with environmentally friendly technologies.