A bioinspired lubricant infused surface with transparency, hot liquid boiling resistance and long-term stability for food applications

Abstract

Inspired by the Nepenthes pitcher plant, the Lubricant Infused Surface (LIS) that exhibits liquid repellency and slipperiness has huge potential in various fields. However, the traditionally used perfluorinated compounds (PFCs) for low surface energy construction and perfluoropolyether for lubricant infusion limited the surface design for food related applications. Considering the potential leaching of the coating, a LIS coating suitable for human consumption is in demand. Therefore, in this article, a transparent LIS coating material with a sprayed hydroxyapatite (HAP) nanowire base layer and oleic acid infusion was fabricated. In addition, the human bone produced hydroxyapatite and biobased oleic acid are non-hazardous, accessible, inexpensive and most importantly heat resistant. The as prepared LIS coating not only exhibited excellent slipperiness at room temperature, but also maintained its slipperiness after boiling or heating at 120 °C; moreover, it maintained its slipperiness for hot liquids. Moreover, the LIS surface maintains slipperiness against food liquids such as green tea, coffee and orange juice. In addition, the LIS surface can retain its slipperiness under extreme conditions such as a high shear rate of 7000 rpm, acid and alkali exposure, 30 days of water immersion, water jetting for 8 h and bending 200 times. Therefore, with the merits mentioned above, the HAP base layered oleic acid infused LIS coating possesses potential in large-scale production and could serve as a guideline for the future design of inorganic based and spray method-based LIS surfaces.