Superwettability-based systems: Basic concepts, recent trends and future prospects for innovation in food engineering

Background Superwettability is a particular state of wettability that has recently contributed to many technological breakthroughs. Nowadays, lots of artificial superwettability systems are fabricated biomimetically, wherein hierarchical micro–nano structures play a substantial role. Scope and approach There are several procedures for manufacturing super(-non)-wettable surfaces, all of which aim to develop surface micro-protrusions with specific average distance and aspect ratio, on which nanoscale roughness is situated. The most common types of these methods are templating, layer-by-layer assembly, electrospinning, plasma treatment, etching, lithography, sol–gel method and coating. Contact angle (CA) and CA hysteresis are two critical measurements that are taken to evaluate the superwettability systems. The development of superwettability strategy in the food engineering is still in the preliminary stages and can be categorized into two main groups: Ⅰ. Superwettability associated with solid–liquid interfaces, which could be gainfully employed in food packaging technology, food coating technology, food processing equipment and liquid–liquid separation; Ⅱ. Food-grade superwetting agents for colloidal systems. Key findings and conclusions superwettability-based systems have recently attracted much attention due to their potential applications in the food industry, including self-cleaning, anti-fogging, anti-icing, anti-bacterial action, anti-fouling, fluidic drag reduction, anti-corrosion, oil–water separation and so on. Superwettability strategy could play a prominent role in the future of food processing and preservation.