Clothing that takes advantage of the energy that comes from our body heat could make the portable devices of the future totally autonomous and maintenance-free. By researching polymers with thermoelectric characteristics, i.e the ability to generate electricity using differences in temperature, material scientists at Chalmers try to create full textiles with the ability to gather and use the waste heat from our bodies.
The project is led by Christian Müller, Associate professor in Polymer technology, and within the project they are trying to use textiles from synthetic polymers to generate electricity.
- One good reason to use textiles to generate electricity is that it is rather easy to create big volumes from textiles. The bigger surface and volume from a material that may create electricity from body heat, the more energy you get. From a fiber it is easy to create a big surface by weaving it, says Anja Lund, one of the researchers in the project.
Anja Lund has just started a postdoc within textile electronics, and one of her tasks in the project is to find suitable methods to use thermoelectric materials in a textile structure. The polymer that has the best thermoelectric characteristics is very hard to produce and also very expensive. Moreover, due to its structure it is very hard to create textiles from it. One way of solving this problem is to mix a very small piece of this polymer with a more common and cheaper polymer and at the same time preserve or even increase the thermoelectric characteristics of the material.
- Normally when you spin synthetic textile fibers you put many kilos of polymer into the machine and get kilometers of fiber, but here we want to create a textile from a few milligrams. My colleagues in my group have since a while back tried combinations of conductive polymers and carrying polymers, and have shown that the solution actually may get better characteristics than the two parts on their own. This is a very good knowledge for our continuous work with producing fibers, says Anja Lund.
Already today there are materials that have the ability to generate electricity from body heat, but those materials are too expensive to be put in large-scale production. Hopefully the research will lead to textiles that are cheap enough to be useful not only in exclusive technologies. With a textile that is easy to produce possibilities for a wide range of applications are given. Imagine to be able to follow every individual in an ant society or to follow migratory birds every move.
- But what inspires me doesn’t have to do with applications. The amazing thing with creating polymer fibers is that the production in itself may structure the chains of polymers in a way that actually increases the conductivity even more. By changing temperatures or other parameters in the process something close to magic happens. From being a pile of plastics suddenly it becomes a source of energy. The challenge is to find the best way of doing this, finding the best parameters to get the best fiber. That is what motivates me, says Anja Lund.
In the two years she will participate in the project she hopes that they will be able to create a fiber and a textile that actually may be used as a source of energy.
But loading your smartphone with your socks will take a while longer, she thinks.
- It will be long before this kind of textile will be out on the market, but hopefully we will have a functioning textile in our lab within the coming years, she says.
Text and image: Mats Tiborn