A Biodegradable Microchip Made of Wood

A research team from the University of Wisconsin-Madison has developed a microchip that could be theoretically be placed in a forest and be degraded by fungus, rendering it as safe as fertilizer.

Kristopher Sturgis

Developed in collaboration with Shaoqin "Sarah" Gong, a UW-Madison professor of biomedical engineering, and the Madison-based U.S. Department of Agriculture Forest Products Laboratory, the team devised a method that involves replacing the substrate of a computer chip with cellulose nanofibril (CNF), a flexible and biodegradable material made from wood, according to a news release.

The group was inspired by how paper is made by felling a tree and extracting individual fibers from it. They decided to take this a step further and break it down to the nanoscale, in an effort to make the material into strong and transparent CNF paper. Once the group decided to try to use materials derived from wood, they needed to address the two most glaring issues: surface smoothness and thermal expansion.

Project leader for the engineering composite science research group at FPL, Zhiyong Cai, has been developing sustainable nanomaterials since 2009. He noted that wood is a natural hydroscopic material that can attract moisture from the air and expand. The group addressed this issue by using an epoxy coating on the surface of the CNF, solving the issue of surface smoothness, while also protecting it from moisture expansion.

The team believes that the advantage of the CNF over other polymers is that it is a bio-based material, while most other polymers are petroleum-based, making them non-biodegradable and possibly harmful to the environment. Bio-based materials have the benefit of being sustainable, biocompatible, and biodegradable. Not to mention that the CNF has a relatively low thermal expansion coefficient when compared to other polymers, making it quite unique when compared to what's already being used in most electronics today.

Most importantly, the group believes their biodegradable chip is comparable to existing chips in terms of performance and functionality.

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