title: Dewetting and deposition of thin films with insoluble surfactants from curved silicone hydrogel substrates.
abstract: We investigate the stabilizing effect of insoluble surfactant monolayers on thin aqueous films. We first describe an experimental platform that enables the formation of aqueous films laden with dipalmitoylphosphatidylcholine (DPPC) monolayers on curved silicone hydrogel (SiHy) substrates. We show that these surfactant layers extend the lifetime of the aqueous films. The films eventually "dewet" by the nucleation and growth of dry areas and the onset of this dewetting can be controlled by the surface rheology of the DPPC layer. We thus demonstrate that increasing the interfacial rheology of the DPPC layer leads to stable films that delay dewetting. We also show that dewetting can be exploited to controllably pattern the underlying curved SiHy substrates with DPPC layers.
authors: Department of Chemical Engineering, Stanford University, Stanford, CA 94305, United States.
authors: M Saad
authors: MS
authors: Bhamla
authors: Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
authors: Caroline
authors: C
authors: Balemans
authors: Department of Chemical Engineering, Stanford University, Stanford, CA 94305, United States. Electronic address: ggf@stanford.edu.
authors: Gerald G
authors: GG
authors: Fuller
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D003261:Contact Lenses; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D012212:Rheology; D012828:Silicones / Q000737:chemistry*; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry*; D017155:Wettability
chemical_list: D012828:Silicones; D013501:Surface-Active Agents; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D015060:1,2-Dipalmitoylphosphatidylcholine
keywords: DPPC; Dewetting; Insoluble surfactant; Interfacial rheology; Lipid deposition; Silicone hydrogel (SiHy) lenses