Keeping VOCs away from delicate technology

A few stray molecules in the air can very easily wreck nanotechnology.

But US engineers have developed a smart cheap, portable container that can keep delicate materials free of even the most difficult substances to clean: volatile organic compounds (VOCs).

The devices could make manufacturing and studying nanomaterials easier, since they dodge the need to use more difficult or expensive cleaning methods.

VOCs are carbon-containing molecules usually emitted from household products like paints and cleaning fluids.

“VOCs are in the air that surrounds us every day,” says Dr Daniel Preston, an assistant professor at Rice University, US, and corresponding author on a paper describing the research, published in Nano Letters.

“They cling to surfaces and form a coating, primarily of carbon. You can’t see these layers with the naked eye, but they form, often within minutes, on virtually any surface exposed to air.”

They can accumulate in amounts that aren’t noticeable in general, but can very easily interfere with nanometre-sized things like features of microfluidics, computer chips or other research and manufacturing at the nanoscale.

The researchers have figured out how to dodge this by designing a smart storage container.

The container has an ultra-clean wall inside, covered in nanometre-sized bumps and dips.

Person stands in lab smiling and holding small silver cylinder
Ph.D. student Zhen Liu with one of the containers. Credit: Gustavo Raskosky/Rice University

“The texturing allows the internal container wall to act as a ‘sacrificial’ material,” says lead author Zhen Liu, a PhD student at Rice.

“VOCs are pulled onto the surface of the container wall, which allows other objects stored inside to remain clean.”

Liu and colleagues have shown that their containers keep their delicate nanostructures cleaner than other methods, like sealed petri dishes or vacuum desiccators (sealable lab equipment designed to keep materials clean or dry).

They’ve also modelled what’s happening inside the container, which they say will help them refine and optimise the containers further.

Image of detailed surface
A scanning electron microscope image (scale bar is 500 billionths of a meter in length) reveals myriad imperfections in this surface. Credit: Image courtesy of Preston Innovation Laboratory/Rice University)

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