Bioinspired, anti-fogging and de-icing transparent surfaces with flexible property

Abstract

In cold environments, natural phenomena like icing, frost, and fog can significantly impede the functionality of optical windows. Consequently, there is a growing demand for optical windows that demonstrate anti-fogging and de-icing characteristics while maintaining flexibility and transparency with high optical clarity. The development of cost-effective and straightforward anti-fogging and de-icing elements encounters various challenges. The remarkable visual acuity of polar bear eyes in challenging weather conditions can be attributed to a tear film that covers the cornea and the thermoregulatory characteristics of their eyeballs. Inspired by the anti-fogging and anti-icing properties of polar bear eyes, a new flexible, transparent surface with heating capabilities has been developed. To address the limitations of conventional slippery surfaces that solely offer anti-fouling properties, a flexible internal heating unit is integrated into the slippery surface through a layered nesting technique to emulate the homothermal features of polar bear eyeballs. The slippery property of the PDMS surface can be attributed to a gel layer containing an auto-secretory lubricant. To preserve its optical properties, a new processing method that combines liquid metal microfluidics and femtosecond laser processing is employed. This technique can create narrow channels with a high length-to-diameter ratio, thereby reducing the impact on the transmission rate. The sample demonstrates self-cleaning, resistance to dust and pollution, and efficient electrical heating properties. Testing on fogging and freezing validates the practicality and effectiveness of these substances for applications in anti-fogging and de-icing.