Tears carry out many tasks to enable our eyes to fully operate. In one function, separate tears join together to form a dynamic film that helps to maintain optical clarity. This process has provided the inspiration for a team from Harvard’s Wyss Institute to create an exciting new material which is able to start and stop running fluids on demand.
The American scientists have developed a nanoporous elastic material with a liquid film on top. When stretched, the elastic causes the film to thin over the substrate and flow into the pores, changing the texture of the liquid’s surface and allowing for fine control over many adaptive responses including the ability to repel a wide range of substances.
Tests – first described in the journal Nature Materials – have shown that the new substance is able to change between two states when pulled and extended, altering from opaque to transparent and at the same time changing from rough to smooth. In its natural state the material is smooth, clear and flat and fluid droplets flow easily off its surface.
The amazing material is continuously ‘turnable’ for transparency and wettability. It repels fluids as it becomes more or less transparent.
Practical ideas for the new product include a tent that could create shade and exclude light on bright, hot summer days, then become transparent and waterproof during dull and wet weather. Another suggestion is for precise self adjusting, self cleaning contact lenses. An industrial use might be in pipelines where flow could be adjusted according to environmental conditions.