Back Issues

JUL/AUG 2013  

Follow us:

Find MICROmanufacturing on TwitterFind MICROmanufacturing on FacebookFind MICROmanufacturing on YouTubeMICROmanufacturing RSS feed

New material for 3-D shaping

A rabbit sculpture, the size of a typical bacterium, is one of several whimsical shapes created by a team of Japanese scientists using a new material that can be molded into complex, highly conductive 3-D structures with features just a few micrometers across, according to the Optical Society. Though its surface has been turned to carbon, the bunny-like features can still be easily observed with a microscope.


Combined with state-of-the-art micro-sculpting techniques, the new resin holds promise for making customized electrodes for fuel cells or batteries, as well as biosensor interfaces for medical uses. The research team, which includes physicists and chemists from Yokohama National University, Tokyo Institute of Technology and the company C-MET Inc. presents its results in a paper published today in the Optical Society’s (OSA) open-access journal Optical Materials Express.

The work opens a door for researchers trying to create conductive materials in almost any complex shape at the microscopic or cellular level, according to the Optical Society. “One of the most promising applications is 3-D microelectrodes that could interface with the brain,” says Yuya Daicho, graduate student at Yokohama National University and lead author of the paper. These brain interfaces, rows of needle-shaped electrodes pointing in the same direction like teeth on combs, can send or receive electrical signals from neurons and can be used for deep brain stimulation and other therapeutic interventions to treat disorders such as epilepsy, depression and Parkinson’s disease.

Currently, researchers have access to materials that can be used to make complex 3-D structures. But the commercially available resins that work best with modern 3-D shaping techniques do not respond to carbonization, a necessary part of the electrode preparation process. In this stage, a structure is baked at a temperature high enough to turn its surface to carbon. The process of “carbonizing,” or charring, increases the conductivity of the resin and also increases its surface area, both of which make it a good electrode.

Unfortunately, this process also destroys the resin’s shape; a sphere becomes an unrecognizable charred blob. What researchers needed were new materials that could be crafted using 3-D shaping techniques but that would also survive the charring process.

The Japanese team, led by Daicho and his advisor Shoji Maruo, sought to develop materials that would fit these needs. Next steps for the team include fabricating usable carbon microstructures, as well as charring the resins at temperatures above the 800° C tested in this study.

Click here to read more.

 

microbunny 1

Two microstructures made with the new material, containing the lowest concentration of RDGE. Left: Pre-carbonization. This circular table and bunny models, just slightly larger than a typical bacterium, were formed using two-photon polymerization, the preferred method of 3-D shaping. Right: The same models after they have been carbonized, or charred. Notice that they shrink significantly but maintain their shape. Credit: Optical Materials Express.

 


microbunny 2 

Two microstructures made with the new material, containing the highest concentration of RDGE. Left: Pre-charring. These pyramid and bunny models did not respond to the preferred method of 3-D shaping, so they were created using an alternative process. Right: Post-charring. Notice that the pyramid and bunny shrink significantly less than those made from the material with a lower concentration of RDGE. Credit: Optical Materials Express.