Laser Textured Non-Wetting Surfaces
Superhydrophobic (or non-wetting) surfaces are important for multifunctional applications in many biological, physical and industrial processes such as self cleaning surfaces, anti-bacterial surfaces and microfluidics. Various techniques for attaining them have been investigated such as lithography, etching, chemical deposition and ultrafast laser processing but all are either relatively timely, complicated or costly . Nanosecond laser texturing is a promising method for attaining superhydrophobic surfaces due to the high processing speed possible, the excellent control of surface roughness from nano- to micro-scale, maskless single-step process and the ability to work with a large range of materials. Researchers in IPaQS at Heriot-Watt University fabricate superhydrophobic surfaces on stainless steel fabricated by using a fast, compact and low-cost process with a commercial infrared nanosecond fiber laser. Processing rates were 2 orders of magnitude faster than with ultrafast lasers, and these superhydrophobic surfaces were used to obtain homogeneous spot deposition (suppressing the coffee-stain effect) for the first time.