Towards development of sustainable metallic superhydrophobic materials

In the present study, an environment friendly, scalable, and cost-effective approach is proposed, combining thermo-mechanical and microwave-assisted hydrothermal processing techniques, resulting in the augmentation of nanoscale structures on metallic surfaces. The thermo-mechanical processing of the aluminium alloy per-formed at different strain rates resulted in significant grain refinement (-1 mu m for processed and -30 mu m for unprocessed samples). After hydrothermal treatment, highly dense and networked nanostructured morphology was evoked by refined grains. Post silanization, samples exhibited high contact angle (theta s > 155 degrees) with a low tilt angle (theta t < 10 degrees) and CAH (< 5 degrees). The low adhesion with water (-16 mu N) for the processed sample (-50 mu N for unprocessed) with utmost refined grains is attributed to the high interfacial energy of Cassie state (EC_B > 1.0J) due to effective entrapment of air. The processed samples were highly de-wetting and mechanically resilient owing to the strong negative capillary pressure (PC > 1100 kPa) generated by highly dense networked nano -structures. As a result of thermo-mechanical processing, samples displayed higher resilience to abrasion, simu-lated rain, and long-term immersion tests with low tilt angles (theta t < 10 degrees) and CAH (< 5 degrees). This paper provides a practical approach to achieve anti-wetting surfaces in various industrial settings.

Automated summary

We propose an environmentally friendly and cost-effective method to enhance nanoscale structures on metallic surfaces through thermo-mechanical and microwave-assisted hydrothermal processing. The processing of the aluminium alloy resulted in significant grain refinement, and after hydrothermal treatment, nanostructured morphology was observed. The processed samples exhibited high water-repellent properties and mechanical resilience due to the unique interfacial energy and negative capillary pressure of the nanostructures. These findings provide practical approaches for achieving anti-wetting surfaces in different industrial settings.