title: Spontaneous, Phase-Separation Induced Surface Roughness: A New Method to Design Parahydrophobic Polymer Coatings with Rose Petal-like Morphology.
abstract: While the development of polymer coatings with controlled surface topography is a growing research topic, a fabrication method that does not rely on lengthy processing times, bulk solvent solution, or secondary functionalization has yet to be identified. This study presents a facile, rapid, in situ method to develop parahydrophobic coatings based on phase separation during photopolymerization. A comonomer resin of ethylene glycol diacrylate (EGDA) and 1H,1H,2H,2H-perfluorodecyl acrylate (PFDA) is modified with a thermoplastic additive (PVDF) to induce phase separation during polymerization. If applied to a glass substrate and photopolymerized, the EGDA/PFDA copolymer forms a homogeneous network with a single glass transition temperature (T(g)) and slight hydrophobicity (θ(w) ∼ 114°). When the resin is modified with PVDF, phase separation occurs during photopolymerization producing a heterogeneous network with two T(g) values. The phase separation causes differences in composition and cross-link density within the network, which leads to local variations in polymerization shrinkage across the nonconstrained material interface. Domains with higher cross-link densities shrink and contract toward the bulk material more dramatically, permitting the formation of rough surfaces with submicron sized spheres enriched in PVDF dispersed in a continuous matrix of EGDA/PFDA copolymer. Both the surface roughness and hydrophobic components in the resin render these surfaces parahydrophobic with θ(w) ∼ 150°, high water adhesion, and a similar morphology to rose petals observed in nature.
authors.affiliation: University of Nice Sophia Antipolis, CNRS, LPMC, UMR 7336 , 06100 Nice, France.
authors.forename: Caroline R
authors.initials: CR
authors.lastname: Szczepanski
authors.affiliation: University of Nice Sophia Antipolis, CNRS, LPMC, UMR 7336 , 06100 Nice, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Darmanin
authors.affiliation: University of Nice Sophia Antipolis, CNRS, LPMC, UMR 7336 , 06100 Nice, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Guittard
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008027:Light; D011095:Polyethylenes / Q000737:chemistry*; D058105:Polymerization; D011145:Polyvinyls / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry*; D017155:Wettability; D005465:Fluorocarbon Polymers
chemical_list: D000180:Acrylic Resins; D011095:Polyethylenes; D011145:Polyvinyls; D012997:Solvents; D014867:Water; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers; C083316:(polyethylene-acrylic acid) copolymer
keywords: adhesion; biomimetics; parahydrophobic; phase separation; superhydrophobic