Micropillars are gentle dust busters

For art conservators and those in the electronics industry, dust can be a serious problem: It damages art and renders devices unusable. Getting rid of particles smaller than 10 µm requires using solvents or other potentially damaging methods. T. Kyle Vanderlick and her colleagues at Yale University have come up with a better option (ACS Appl. Mater. Interfaces 2016, DOI: 10.1021/acsami.5b09154). They made an array of cylindrical polydimethylsiloxane (PDMS) pillars 2 to 50 µm in diameter. Electrostatic forces enable this material to lift 0.26- to 7.75-μm spherical silica particles, a proxy for dust, from thin polymethyl methacrylate (PMMA) films—which simulate a layer of delicate acrylic paint. The particles stick to the pillars’ flat tips, but when the array makes contact with another dusty spot, new silica particles push the old ones to the sides of the pillars. The ability to regenerate a dust-grabbing PDMS surface that can attract additional dust particles is a key advantage of the pillar array. Flat PDMS sheets can’t clean themselves. The researchers estimate that the array can clean a dust-covered area nine times its size.