Porous silk fiber traps heat, hides a rabbit from IR camera

To mimic polar bear hair and to turn it into a weavable thread, the researchers turned to another natural fiber: silk. Instead of using the silk fiber directly, the silk was purified and dissolved in a liquid. The solution was then spun and extruded through a ring that was cooled.

The idea is that the cold ring freezes the silk as it passes through. Depending on the temperature of the ring and the speed at which the fiber is drawn through the ring, however, the silk can start to freeze before it reaches the ring. So researchers tried to hit a sweet spot in balancing temperature and draw speed.

If the ring is too cold, everything freezes in place and the pores will be oriented in random directions. If the ring is not cold enough, then the silk protein has time to close up and remove the pores entirely.

Source: arstechnica.com