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.
A brilliant white surface gives furniture and other objects a clean, bright and modern appearance. To date, titanium dioxide has been the standard pigment used to color varnishes, paints and plastics, as well as cosmetics, food, chewing gum and tablets white. However, the pigment has been criticized. "Titanium dioxide has a very high refractive index, it reflects incident light almost completely, but has the disadvantage that its particles do not degrade and therefore pollute the environment in the long term," says Professor Hendrik Hölscher from the Institute of Microstructure Technology (IMT) at KIT. There are also concerns that titanium dioxide could potentially be harmful to health.
"We avoid the use of pigments that are harmful to the environment and health by creating porous polymer structures with comparably high dispersion," says Hölscher. He and his team were inspired by the white beetle Cyphochilus insulanus, whose scales appear white thanks to a special nanostructure of its chitin shell. "Based on this model, we use polymers to produce solid, porous nanostructures that resemble a sponge," says Hölscher, who heads the Biomimetic Surfaces research group at the IMT. Just like the bubbles in shaving or bath foam, the structure scatters the light, making the material appear white. The new technology for a cost-effective and harmless white appearance is suitable for a wide variety of surfaces.
