A soft, flexible fiber with a 1000 times more capacitance than a coaxial cable could lead to smarter textiles, say its inventors at Huazhong University of Science and Technology in China.

Their idea is to create a simple rolled capacitor from a sheet of conducting polymer sandwiched between two insulating sheets of low density polyethylene. They then roll this sandwich into a cylinder and encase it in high density polyethylene.

They heat it and then extrude it through a tiny hole to form a fiber with a diameter of less than a millimeter. If the conditions are just right, the plastics all stretch in exactly the same way so that the internal structure of the fiber is just a smaller version of the original.