Scientists at Harvard University’s Wyss Institute in the US have developed a new adaptive material inspired by the behaviour of human tears. The material can vary in transparency and texture thanks to its unique two-layered structure.
The material is made from a liquid film supported by a nano-porous elastic substrate. When the fabric is stretched, the substrate becomes deformed, allowing liquid to drain into the elastic’s pores and causing the material’s smooth surface to roughen. Stretching the fabric also makes the material more opaque – the colour-changing fibre developed by scientists earlier this year functions in a similar way.
The Harvard team was inspired by the way human tears group together to form a dynamic liquid film to coat eyes, protecting them from dust and bacteria while maintaining optical functions.
The dynamic nature of this new material makes it far more versatile than other adaptive fabrics that can only switch between two states – such as from hydrophilic (water-loving) to hydrophobic (water-hating).
“In addition to transparency and wettability, we can fine-tune basically anything that would respond to a change in surface topography, such as adhesive or anti-fouling behaviour,” said Yao Xing, lead author of the study.
Possible applications range from light adjustable fabrics for tents to self-cleaning contact lenses. In the future this technology might drive the development of responsive buildings that can adapt to a changing environment.
Look out for our next edition of Materials Focus in June for more material innovations.