Is directed assembly the 3-D printing of tomorrow?

3-D printing is going to change the world in the next few years...

(PHYSORG)- Ahmed Busnaina, the William Lincoln Smith Professor and director of the NSF Nanoscale Science and Engineering Center for High-rate Nanomanufacturing at Northeastern, has developed a method called directed assembly that he calls the 3-D printing of tomorrow. It is faster, cheaper, and more versatile than traditional 3-D printing, and he said it could enable a wave of innovation not currently feasible. Here, Busnaina was asked to describe this process and its potential impact in areas such as health, electronics, and the environment.

The modern 3-D printer is basically a specialized ink-jet printer. It uses a printer head with special ink that could contain a polymer, particles, or nanotubes suspended in solution, or really anything. It prints line by line, so products requiring higher resolution or large areas take a very long time.

What we have developed at our center is a system that's like newspaper printing or printing money, where you have a big plate, you put ink on it, and bang: One hit, you're done. Only here, the ink is made of very small and very sensitive nanoparticles attracted to the template using electrophoresis, so we have to pick exact dimensions and materials.

We put a template with a pattern represented by nanowires into a solution that is similar to ink, but very dilute. Then we apply a couple of volts so that nanoparticles in the ink are drawn to the nanowires. Then we take out the template and transfer the assembled nanoparticles to a surface of either a hard or flexible substrate. That would be the first layer of a device, which takes about a minute or two. A sensor may have just a few layers, where advanced electronics may have 10 layers or more.

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