Protection from direct sunlight – skin temperature drops by up to 3.8 degrees Celsius

A new textile fabric developed by researchers at the University of South Australia (https://www.unisa.edu.au/) and Zhengzhou University (http://international.zzu.edu.cn/) lowers skin temperature by two degrees Celsius in direct sunlight and by as much as 3.8 degrees at night compared to uncovered skin.

Regulation without energy consumption

Unlike cotton fabrics, which tend to trap heat and sweat, the material made of polylactic acid/boron nitride nanolayers actively dissipates heat and keeps the skin dry because it is permeable to moisture.

‘We wanted to develop a smart, sustainable fabric that passively regulates body temperature, not through the use of energy, but through the use of natural physical processes,’ says Jun Ma from the university in Australia.

Surprising properties

Using electrospinning, in which a liquid polymer is pressed through a fine nozzle and the resulting fibre is stretched and dried using an electric field, the experts embedded the boron nitride nanolayers in a biodegradable polylactic acid fibre matrix.

These fibres are woven into fabrics using traditional techniques. The result is a white fabric with exceptionally effective sun reflection, five times higher breathability than cotton and the ability to release heat into the environment.

‘The combination of high solar reflectivity, heat radiation and moisture regulation ensures that the wearer feels noticeably cooler and drier,’ emphasises materials scientist Ma. This is beneficial for people working in the construction industry, mining or agriculture.

Polylactic acid is cross-linked lactic acid. The latter is produced by fermenting sugar and starch. These monomers are linked together at elevated temperatures in the presence of a catalyst to form long chains. The result is a plastic with properties similar to those of a petroleum-based polymer.