When liquid meets gas, a unique zone forms. Variable by nature, molecules can cross from one state to another, combining in unique ways to either desirable or unwanted ends. From heat escaping a mug of coffee to increasing molecular concentrations in chemical solutions, gas-liquid interfaces are ubiquitous across nature and engineering. But a lack of tools capable of precisely controlling such gas-liquid interfaces limit their applications — until now.

Researchers based at Osaka Prefecture University have developed the first controllable gas-liquid interface at the nanoscale. They published their design and experimental results on October 14 in Nano Letters.

«Whether it’s engineered or occurs in nature, gas-liquid interfaces play an important role in numerous chemical and biological processes,» said paper author Yan Xu, associate professor of chemical engineering in the Graduate School of Engineering at Osaka Prefecture University. «Nanoscale gas-liquid interfaces have been randomly generated in carbon nanotubes and porous membranes, for example, but fabricating controllable, nanoscale versions is still challenging because nanofluidic channels are too small to make use of conventional approaches to surface control.»

Fluidic devices help researchers capture target molecules and examine specific properties, as well as force interactions through nanoscale channels designed with precisely controlled geometry, Xu said.

In microfluidic devices, which contain channels about 1,000 times larger than those in nanofluidic devices, the surface of the channels can be changed to attract or reject specific molecules.

«Such surface modification is commonly used for microfluidic channels, but its applicability for nanofluidic channels is almost never explored,» Xu said.

Story Source: Materials provided by Osaka Prefecture University. Note: Content may be edited for style and length.