Reversible wettability of hybrid organic/inorganic surfaces of systems upon light irradiation/storage cycles. (23rd August 2010)

• Record Type: Journal Article
• Authors: Athanassiou, Athanassia; Cingolani, Roberto; Caputo, Gianvito; Cortese, Barbara; Gigli, Giuseppe; Nobile, Concetta; Cozzoli, P.
• Is Part Of: International journal of nanomanufacturing. Volume 6:Number 1/2/3/4(2010)
• Page Start: 312
• Page End: 323
• Publication Date: 2010-08-23
• Subjects: reversible wettability -- hydrophobicity -- hydrophilicity -- TiO2 nanorods -- SU-8 polymer -- photopatterning -- UV laser light -- titanium dioxide -- nanotechnology -- microroughness -- nanoroughness -- microfluidic devices -- microfluidics -- surface wettability; Nanostructured materials industry -- Periodicals; Nanotechnology -- Periodicals; 620.505
• Languages: English
• ISSNs: 1746-9392

Abstract

In this work we present hybrid organic/inorganic structures that can exhibit reversible surface wettability, altered in a controllable manner. In particular, we use the method of photo-patterning to produce polymeric SU-8 pillars of specific geometries, onto which we subsequently deposit colloidal TiO2 nanorods. In this way, we combine the microroughness of the polymeric pillars with the nanoroughness of the nanorod-coating to create highly hydrophobic surfaces. The hydrophobicity of these systems can be changed reversibly into hydrophilicity upon irradiation of the hybrid structures with pulsed UV laser light. This behaviour is due to the well-known property of TiO2, that becomes superhydrophilic upon UV light irradiation. This property is reversible and we monitor the recovery of our hybrid polymeric/inorganic-nanorods structures to their initial hydrophobic character upon dark storage and heating. The wetting behaviour has been modelled and analysed according to the surface geometry. The direct implementation of such structures into microfluidics devices is demonstrated.