A team from Shenzhen Institutes of Advanced Technology, Chinese Academy of Science developed micro-capsules that can cool you off in summer, and keep you warm in winter, when they are used in clothing.
“The capsules will help clothes maintain the comfortable temperature of 28 degrees Celsuis. When the external environment is higher than 28 degrees, the capsules will automatically absorb heat. When it is below 28 degrees, it will automatically release heat,” said Yu Xuefeng, director of material and interface center of Shenzhen Institutes of Advanced Technology.
The team used paraffin wax as the phase-change material to adjust temperature. Common phase-change material includes water.
“Paraffin wax automatically solidifies, which releases heat, and melts, which absorbs heat. In order to make use of this property, we either used polyurethane or organosilicon to form capsules so as to seal the paraffin wax,” said Yu.
Yu suggested that they used paraffin wax because of its low cost. The biggest challenge is to improve paraffin wax’s performance and achieve large-scale production of the micro-capsules at a low cost.
“Paraffin wax, as a common industrial material, performs differently when it is made using different purification methods. The methods used by our team can produce paraffin wax that has a higher enthalpy and a better performance,” said Yu.
The team led by Yu also used advanced materials and technologies to avoid formaldehyde in the capsules.