Even more interesting is the fact that the method allows cutting the device in any shape or size, at it requires only paper and scissors. This makes it a promising tool for manufacturing large-scale nanofluidic devices, without having to invest in expensive lithography techniques.
Published in the Journal of the American Chemical Society, the study reveals how by stacking up sheets of cheap graphene oxide, a flexible paper with thousands of channels is created, allowing a flow of ions. The researchers cut the sheets in rectangular shapes, although using a pair of regular scissors the “paper” could be cut in any desired shape. The paper was then covered in polymer, the ends of each piece were drilled with tiny holes, so that they are exposed, and then they were filled with an electrolyte solution.
Electrodes, placed on each end of the rectangles tested the electrical conductivity of the new devices.
Jiaxing Huang, who carried out the research together with postdoctoral fellow Kalyan Raidongia, was surprised creating the device was so easy, and yet no one has thought to use the space between sheet-like materials as a flowing channel before.
Huang, an assistant professor of materials science and engineering and the Morris E. Fine Junior Professor in Materials and Manufacturing in the McCormick School of Engineering and Applied Science, pointed out that although many have studied the mechanical properties of graphene oxides, layering graphene oxide paper to generate nanofluidic channels is a brand new idea.
The observed current was higher than normal, and the devices worked regardless of their position. This was due to the concentrating effect of the nanochannels which is lacking in their bulk channel counterparts.
The researchers are convinced that it will be equally as easy to scale up the size of the devices, because there is no limit to the number of layers, and consequently channels, in a piece of paper. The only requirement would be to have more graphene oxide sheets in a paper, or to stack a number of papers together. Larger devices would mean handling of larger quantities of electrolyte.
To manufacture very massive arrays of channels, one only needs to put more graphene oxide sheets in the paper or to stack up many pieces of paper. A larger device, of course, can handle larger quantities of electrolyte.