title: Superhydrophobicity due to the hierarchical scale roughness of PDMS surfaces.
abstract: Wettability control has been widely investigated in the last decades for technological applications such as microfluidic devices and self-cleaning surfaces by modifying both the chemical composition and the geometric structure of the surfaces. Inspired by the typical morphology of superhydrophobic leaves (such as lotus leaves), we have developed a dual-scale roughness, micro- and nanosized, on polydimethylsiloxane (PDMS) surfaces. By combining different geometric parameters and plasma treatment conditions, the structures were controlled hierarchically, at different independent length scales. Both the microsized replicated pillars and the nanosized etched posts tuned the wettability of the PDMS surfaces in a very simple way, up to contact angles of 170 degrees . Furthermore, changes in the influence of micro- and nanoscale geometrical structures were investigated. Hysteresis and contact angles of water droplets are evaluated as a combined effect of micropillars and a superimposed roughness, resulting in high advancing contact angles and low sliding angles.
authors.affiliation: NNL, National Nanotechnology Laboratories of CNR-INFM, Distretto Tecnologico, Università del Salento, Via Arnesano 16, 73100, Lecce, Italy. barbara.cortese@unile.it
authors.forename: Barbara
authors.initials: B
authors.lastname: Cortese
authors.forename: Stefania
authors.initials: S
authors.lastname: D'Amone
authors.forename: Michele
authors.initials: M
authors.lastname: Manca
authors.forename: Ilenia
authors.initials: I
authors.lastname: Viola
authors.forename: Roberto
authors.initials: R
authors.lastname: Cingolani
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Gigli
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D010316:Particle Size; D011108:Polymers / Q000737:chemistry; D012828:Silicones / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D004129:Dimethylpolysiloxanes; D004852:Epoxy Compounds; D011108:Polymers; C520895:SU-8 compound; D012828:Silicones; D014867:Water; C013830:baysilon