Imagine building structures that are more than a hundred times smaller than the human hair. Well, thats not too difficult. Every PC today has such devices where millions of transistors are patterned on the surface of a silicon chip.
Now think of doing this same thing with an ink and ‘directly writing’ such small structures using a pen like device. This in fact is a much more difficult job to accomplish. However, the researchers in the Lewis group in the Department of Material Science and Engineering at the University of Illinois are making significant advances in doing this.
They recently were featured in the journal, Nature and this press release gives some more information about this story.
One of my colleagues, Sung Joon is jointly advised by Prof. Lewis and works on improving the flowability of such polyelectrolyte colloidal inks.
Exciting stuff!
Here is an excerpt from their communication.
Applications are emerging that require the creation of fine-scale structures in three dimensions — examples include scaffolds for tissue engineering, micro-fluidic devices and photonic materials that control light propagation over a range of frequencies. But writing methods such as dip-pen nanolithography and ink-jet printing are either confined to two dimensions or beset by wetting and spreading problems. Here we use concentrated polyelectrolyte inks to write three-dimensional microperiodic structures directly without using masks. Our technique enables us to write arbitrary three-dimensional patterns whose features are nearly two orders of magnitude smaller than those attained with other multilayer printing techniques.
Nature 428, 386 (25 March 2004)