Polymer films that are extremely thin and have high light scattering properties are the result of a new process from the Karlsruhe Institute of Technology (KIT). The cost-effective material can be applied industrially to a wide variety of objects to give them an attractive white appearance. The process can also make products more environmentally friendly and replace the titanium dioxide previously used for "whitening".
To this end, the researchers have developed porous polymer structures with comparably high scattering, inspired by the white beetle Cyphochilus insulanus, whose scales appear white thanks to a special nanostructure of its chitin shell. Based on this model, they produce solid, porous nanostructures from polymers that resemble a sponge. Like the bubbles in shaving or bath foam, the structure scatters the light, making the material appear white. The polymer films are extremely thin, flexible and light, yet mechanically stable and can be applied industrially to various products. At a thickness of nine micrometers, they reflect more than 57% of the incident light. 80 to 90% can be achieved with a thicker film. For the development, the sponge-shaped microstructure was applied to acrylic glass. However, the process can be transferred to many other polymers.
