‘Smart’ Textile Heats or Cools
I spent one summer during my college years working in a meat-packing plant. My job was to stand adjacent to a conveyor line, wearing multiple layers of clothing and gloves, and pack stacks of frozen hamburger patties in a box. As long as I kept up with the feed of burgers traveling toward me interminably, I was doing a good job.
Whenever I think of that job, I am reminded of the famous scene from “I Love Lucy,” where Lucy cannot keep up with the conveyor line in the candy factory and starts stuffing them in her mouth. (Fortunately, I did not have to resort to similar tactics!) The other thing I remember is how cold my hands would get despite wearing multiple layers of gloves. All these years later, my hands still turn white when shopping in the frozen foods section. (I now know that this is due to our family’s propensity for poor circulation in our hands.)
So, I read with interest that researchers at Stanford University had developed a reversible fabric that, without the wearer expending energy or effort, could keep the skin at a comfortable temperature. The polyethylene material, no thicker than kitchen wrap, is manufactured with nanoscale materials that allow it to heat or cool the wearer, depending on which side of the material faces out. Originally developed to reduce the need for summer comfort cooling and indoor temperature control, the researchers soon realized that heating was just as essential in colder climates.
The Stanford team found that stacking two layers of material with different abilities to release heat energy, and then placing them between layers of the cooling ethylene, would create a fabric that could warm or cool the wearer to suit his or her personal comfort. Says postdoctoral fellow Po-Chun Hsu, the first author on research published in “Science Advances,” the sandwiched material can increase a person’s range of comfortable temperatures over 10°F (5.5°C). It is even possible, he says, that some climates might never need air conditioning or central heating.
Anyone who was walked the hallways of a shopping mall knows that unless the smart fabric can also be made in many fashion fabrics and styles that prioritize stylishness over function or form, comfort heating and cooling will be needed for some time to come. Functional uses of such a fabric, however, in areas of hot work or in below freezing areas such as freezers seem primed for such a material.