Materials Science

A Coat To Fit Many

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Science  21 Feb 2014:
Vol. 343, Issue 6173, pp. 818
DOI: 10.1126/science.343.6173.818-c

Applying a coating is a useful way to change the surface properties of a material. Common examples include antiglare coatings on lenses or anticorrosion coating on metals. Flat surfaces can be uniformly coated relatively easily, but uniformly coating a complex, porous three-dimensional (3D) shape can be much more challenging. Nguyen et al. develop a method to coat such structures conformally by using membrane precursors dissolved in a mixed solvent that includes a component that will selectively swell the object that needs to be coated. Initial experiments used polydimethylsiloxane (PDMS) as the membrane precursor and poly(lactic acid) (PLA) fibers as the material to be coated in and explored the role of solvent composition, precursor concentration, and exposure time on the thickness of the coating that formed. The precursor infiltrates the thin swollen surface region of the PLA fibers, becomes trapped there upon unswelling, and can be cured into a solid conformal coating on heating. The PLA can be removed through selective vaporization, leaving behind the PDMS membrane that retains the geometry of the original PLA fiber or more complicated initial shapes generated using 3D printing. This technique works for a wide range of precursor materials, including acrylic, epoxy, and polyurethane.

ACS Appl. Mater. Interfaces 10.1021/am4053943 (2014).

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