A research team from National University of Singapore (NUS) used 3D printing to produce novel film that has the ability to evaporate sweat from human skin. This novel film can be used in underarm pads, insoles and shoe linings.
During the testing, researchers demonstrated how moisture absorbed by the film is harnessed to power wearable electronic devices like watches and fitness trackers.
“Sweat is mostly composed of water. When water is evaporated from the skin surface, it lowers the skin temperature and we feel cooler,” explained research team leader Tan Swee Ching, of the NUS Department of Material Science and Engineering. “In our new invention, we created a novel film that is extremely effective in evaporating sweat from our skin and then absorbing the moisture from sweat.
3D printing of the film
Researchers used two hygroscopic chemicals cobalt chloride and ethanolamine that can attract water molecules absorbed from surrounding environment. According to researchers, moisture-absorbing 3D printed film takes 15 times more moisture.
As the moisture starts absorbing, the film keeps changing color from blue to purple, and then to pink. When the film is exposed to the sunlight, it release the absorbed water and regenerate itself.
“The prototype for the shoe insole was created using 3D printing,” said research team co-leader Professor Ding Jun, also of NUS. “The material used is a mixture of soft polymer and hard polymer, thus providing sufficient support and shock absorption.”
Ching, on the other hand said, “Using the underarm pad, shoe lining, and shoe insole embedded with the moisture-absorbing film, the moisture from sweat evaporation is rapidly taken in, preventing an accumulation of sweat and provides a dry and cool microclimate for personal comfort.”
Powering Wearable electronics
Taking a step further, researchers looked for ways to make full use of sweat harnessed by the film. They designed and created a wearable energy-harvesting device made up of eight electrochemical cells and used 3D printed film.
Once absorbed, each EC generated around 0.57 volts of electricity and the device generated enough energy to power a light-emitting diode.
3D printing in wearable technology
3D printing is playing a major role in creating and designing wearable technology since long time. In recent times, 3D printing is explored as the potential method for producing electronic wearables including fitness trackers.
In 2015, 3D printing was used to create a helmet that can change shapes according to the wearer’s brainwaves. In the same year, MIT designers used FDM for creating a 3D printed shoe that can change shape.
