The electronics industry, art conservators, and aerospace engineers can face major problems caused by micrometric and sub-micrometric contaminant particles. Or, as most of us call it, dust.
These nanoparticles can stop a cellphone from functioning or steal the vividness from a painting’s colors.
Taking a cue from the forces of static cling and the physics behind gecko feet, the lab of Yale School of Engineering & Applied Science Dean T. Kyle Vanderlick has come up with a promising tool in the battle against dust.
“This wouldn’t have happened without the art scientists and conservators at the IPCH (the Yale Institute for the Preservation of Cultural Heritage) working with the researchers in our lab,”
Vanderlick said. She added that the project is particularly characteristic of Yale, where collaborations between disciplines are strongly encouraged.
The lab worked with Yale art conservators in developing the technology. Cindy Schwartz, assistant conservator of painting at the Yale University Art Gallery, said dust is a problem for her, especially with modern paintings featuring acrylic paint.
“Acrylic paints are incredibly porous, so anything you’re putting on the surface could get into the pores, and then work from the insides of the pores to soften the paints,” Schwartz said
The new technology has the potential to solve this long-standing problem.
“Dust is something at the nanometer level,” Vanderlick said. “And there’s a lot of interesting thin film, surface, and interfacial physics associated with the preservation of art.”
Lead author Hadi Izadi, a postdoctoral associate, is quite familiar with fibrillar structures and micropillars. His previous research examined the mystery of how geckos effortlessly stick to walls.
Deceptively Simple Solution
It turns out that a lot of the stickiness has to do with electrostatic charges and the microscopic pillars on the pads on their feet. Applying some of this science to cleaning microparticles made sense, he said.
The Yale researchers’ solution is deceptively simple. In the lab, Izadi holds up what looks like an ordinary plastic sheet. It’s actually an elastic and non-sticky polymer, polydimethylsiloxane (PDMS). PDMS is the compound that made Silly Putty fun for kids in the 1960’s.
Put it under a microscope, and you can see millions of tiny columns. Depending on the size of dust particles you’re removing, the pillars range from 2 to 50 micrometers in diameter. Bigger particles require bigger pillars.
The micropillar structures used for dust cleaning, however, differ from those of geckos in that they’re designed specifically not to stick. The PDMS polymer has minimal interaction with the substrate, whether it’s an iPhone or a sculpture, but it produces enough electrostatic charge to detach the dust particles.
Once you match up a sheet with the appropriately sized pillars, cleaning is simply a matter of tapping the polymer on the surface. Particles absorbed by the polymer go around the pillars. Tests on various surfaces in the lab have shown total cleaning of silica dust particles and no damage to the surface.
Although her lab is new to art preservation, Vanderlick noted, there’s much to engage researchers in her field.
Image: Microscopic images of silica dust particles lifted by micropillars, 50 micrometers in diameter. Credit: Vanderlick Lab