title: Robust non-wetting PTFE surfaces by femtosecond laser machining.
abstract: Nature shows many examples of surfaces with extraordinary wettability,which can often be associated with particular air-trapping surface patterns. Here,robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE). The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters,both of which make it a strong candidate for industrial applications.
authors.affiliation: Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, QC H3A 0C5, Canada. fang.liang@mail.mcgill.ca.
authors.forename: Fang
authors.initials: F
authors.lastname: Liang
authors.affiliation: Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, QC H3A 0C5, Canada. jorge.lehr@mail.mcgill.ca.
authors.forename: Jorge
authors.initials: J
authors.lastname: Lehr
authors.affiliation: Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, QC H3A 0C5, Canada. lisa.danielczak@mcgill.ca.
authors.forename: Lisa
authors.initials: L
authors.lastname: Danielczak
authors.affiliation: Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, QC H3A 0C5, Canada. richard.leask@mcgill.ca.
authors.forename: Richard
authors.initials: R
authors.lastname: Leask
authors.affiliation: Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, QC H3A 0C5, Canada. anne.kietzig@mcgill.ca.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Kietzig
mesh_terms: D006046:Gold / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007834:Lasers; D011138:Polytetrafluoroethylene / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D014867:Water; D006046:Gold; D011138:Polytetrafluoroethylene
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