title: Micropatterned Surfaces for Atmospheric Water Condensation via Controlled Radical Polymerization and Thin Film Dewetting.
abstract: Inspired by an example found in nature, the design of patterned surfaces with chemical and topographical contrast for the collection of water from the atmosphere has been of intense interest in recent years. Herein we report the synthesis of such materials via a combination of macromolecular design and polymer thin film dewetting to yield surfaces consisting of raised hydrophilic bumps on a hydrophobic background. RAFT polymerization was used to synthesize poly(2-hydroxypropyl methacrylate) (PHPMA) of targeted molecular weight and low dispersity; spin-coating of PHPMA onto polystyrene films produced stable polymer bilayers under appropriate conditions. Thermal annealing of these bilayers above the glass transition temperature of the PHPMA layer led to complete dewetting of the top layer and the formation of isolated PHPMA domains atop the PS film. Due to the vastly different rates of water nucleation on the two phases, preferential dropwise nucleation of water occurred on the PHPMA domains, as demonstrated by optical microscopy. The simplicity of the preparation method and ability to target polymers of specific molecular weight demonstrate the value of these materials with respect to large-scale water collection devices or other materials science applications where patterning is required.
authors.affiliation: Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Ian
authors.initials: I
authors.lastname: Wong
authors.affiliation: Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia.|School of Physical Sciences (Chemistry), The University of Tasmania , Sandy Bay, Tasmania 7005, Australia.
authors.forename: Guo Hui
authors.initials: GH
authors.lastname: Teo
authors.affiliation: School of Chemistry F11, The University of Sydney , Sydney, New South Wales 2006, Australia.
authors.forename: Chiara
authors.initials: C
authors.lastname: Neto
authors.affiliation: Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia.|School of Physical Sciences (Chemistry), The University of Tasmania , Sandy Bay, Tasmania 7005, Australia.
authors.forename: Stuart C
authors.initials: SC
authors.lastname: Thickett
keywords: biomimicry; controlled radical polymerization; dewetting; poly(hydroxypropyl methacrylate); water collection; wettability