Laser textured surface gradients

Ta Van Duong, Andrew Dunn, Thomas J. Wasley, Ji Li, Robert W. Kay, Jonathan Stringer, Patrick J. Smith, Emre Esenturk, Colm Connaughton, Jonathan D. Shephard

Research output: Contribution to journalArticlepeer-review

74 Citations (Scopus)
151 Downloads (Pure)


This work demonstrates a novel technique for fabricating surfaces with roughness and wettability gradients and their subsequent applications for chemical sensors. Surface roughness gradients on brass sheets are obtained directly by nanosecond laser texturing. When these structured surfaces are exposed to air, their wettability decreases with time (up to 20 days) achieving both spatial and temporal wettability gradients. The surfaces are responsive to organic solvents. Contact angles of a series of dilute isopropanol solutions decay exponentially with concentration. In particular, a fall of 132° in contact angle is observed on a surface gradient, one order of magnitude higher than the 14° observed for the unprocessed surface, when the isopropanol concentration increased from 0 to 15.6 wt%. As the wettability changes gradually over the surface, contact angle also changes correspondingly. This effect offers multi-sensitivity at different zones on the surface and is useful for accurate measurement of chemical concentration.
Original languageEnglish
Pages (from-to)583–589
Number of pages7
JournalApplied Surface Science
Early online date9 Mar 2016
Publication statusPublished - 15 May 2016


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