The production cycle of ASSETm. (Credit: Xiaohong Lan, University of Groningen)

Polymer scientists have developed a starch-based polymer that makes it possible to create a fully biodegradable soft material for sensors. The resulting ‘Advanced Scalable Supersoft Elastic Transparent material’ (ASSETm) has all the right properties to seal in electrodes to produce sensors.

To create a biodegradable polymer, the researchers started out with a backbone of starch-derived dextrin carbohydrates. Most polymer backbones contain chemical bonds, which are very strong. The dextrin backbone can be degraded by natural enzymes that are present in soil.

Long fatty acid tails were added to the dextrin in the backbone, and the researchers were able to use the fatty acids added per glucose unit to regulate the hydrophobicity of the polymer.

The enzymes that degrade the polymer require water, so if a material is too hydrophobic, they cannot do it. If the polymer is too hydrophilic, on the other hand, the material will not have the right properties.