Analyte enrichment and sensitive detection over nanosecond laser textured stainless steel superhydrophobic surfaces

• Published in: Materials chemistry and physics Vol. 302; p. 127755
• Main Authors: Ahlawat, Sunita, Singh, Amarjeet, Mukhopadhyay, Pranab K., Singh, Rashmi, Dhamgaye, V.P., Dixit, S.K., Bindra, K.S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2023
• Subjects: Analyte enrichment; Nanosecond laser surface texturing; Superhydrophobic; Nanosecond laser surface texturing; Superhydrophobic; Analyte enrichment
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2023.127755

In this report, we have investigated the use of nanosecond laser texturing produced superhydrophobic surfaces for enrichment and sensitive detection of analytes. We have shown that by carefully choosing the laser processing parameters, the superhydrophobic surfaces capable of maintaining a small (5 μL) aqueous droplet in spherical shape till the last stage of evaporation and hence enabling the droplet to deposit its entire content over ∼80–100 μm size residual spot upon complete evaporation, can be prepared. The spot was found to get formed by bridging over the micro structures suggesting that the droplet remained suspended over the structures i.e. did not penetrate the structures till the very end of the evaporation process. By performing fluorescence spectroscopy of the residual spot, Rhodamine 6G could be detected at an ultra-low concentration of 10−18 molL−1 in a 5 μL water droplet. When compared with the results obtained on unprocessed stainless steel substrate, these superhydrophobic steel surfaces were found to provide four orders of magnitude enhancement in the lowest detectable concentration of Rhodamine 6G. [Display omitted] •Nanosecond laser texturing produce superhydrophobic (SH) stainless steel substrates.•Certain texturing parameters produce SH surfaces having clustered nano-wire structures.•Droplet evaporation over such SH surfaces resulted in footprints of<100 μm.•Fluorescence spectroscopy of the footprint detected 10−18 molL−1 of Rhodamine 6G.