Natural polysaccharides such as chitin and chitosan are excellent sources for new materials with exceptional properties. Here we present innovative applications of the biopolymer derived from crustaceans or mushrooms in bulletproof coatings and smart windows.
Bulletproof coatings with chitosan
Researchers from Houston university are using chitosan and 3D printing to create multilayered coatings that could applied for bullet proof waistcoats to protect the wearer against bullets, lasers, toxic gas and other dangers. The biodegredable polymer could be a good alternative for currently used petroleum-based platics. The project of Alamgir Karim, Dow Chair Professor of chemical and biomolecular engineering is funded by the U.S. Department of Defense.
The goal is to engineer a multilayer system compromising of a energy absorbing crush-layer, a toxic gas absorbing layer with charcoal nanoparticles dispersed in the chitosan, and a textile adhesion layer.
Results of this research could also be interesting for new materials in automobile and construction industrie.
Self-illuminating windows with chitosan for rainy days
Researchers from Korea developed a new humidity sensor based on a chitosan hydrogel, which in the future could enable "smart" windows to react to humidity. The development of the sensor is based on Fabry-Perot interference, which acts as an optical filter that filters out a narrow-band spectrum from a broadband spectrum.
The research team combined a metal-hydrogel-metal resonator with a solar cell to create a humidity sensor. The chitosan hydrogel expands depending on the ambient humidity, which changes the resonance wavelength of the transmitted light. In combination with a solar battery, the light energy can be converted into electricity and used as a humidity sensor. Unlike conventional optical humidity sensors, this newly developed, chitosan-based sensor is independent of the type of light. In addition, an external energy source is not required and the humidity can already be determined based on the filter color. The sensors could enable the development of intelligent windows that change color depending on the external humidity.
J. Jang, et al. ‘Self‐Powered Humidity Sensor Using Chitosan‐Based Plasmonic Metal–Hydrogel–Metal Filters.’ Advanced Optical Materials (2020). DOI: 10.1002/adom.201901932