Researchers have unveiled innovative wearable technologies that not only produce electricity from human movements but also enhance user comfort. This development comes from a deeper knowledge of materials that improve the feel of textiles and generate power when they come into contact with another surface.
Researchers have unveiled innovative wearable technologies that not only produce electricity from human movements but also enhance user comfort. This development comes from a deeper knowledge of materials that improve the feel of textiles and generate power when they come into contact with another surface.
The focus here is on molecules known as amphiphiles, frequently used in everyday products to lessen friction against skin. A good example is their use in diapers to minimize chafing.
“Our goal was to create a model that provides us with an in-depth understanding of how various amphiphiles influence the surface friction of different materials,” explains Lilian Hsiao, a lead author of the study and associate professor of chemical and biomolecular engineering at North Carolina State University. “This model aids in understanding the molecular mechanisms behind friction reduction and can be utilized by engineers to customize material properties for various uses.”
“We subsequently initiated a series of experiments to investigate whether we could utilize amphiphiles to adjust materials and integrate them into haptic energy harvesters,” adds Saad Khan, co-lead author and INVISTA Professor of Chemical and Biomolecular Engineering at NC State. “Specifically, we aimed to find out if we could harness energy from friction with amphiphile-enhanced materials. It turned out that we could not only generate electricity but also reduce the friction experienced by users wearing these materials.”
In essence, the researchers discovered that they could use amphiphiles to make wearing fabrics with smooth surfaces that are comfortable against the skin.
Additionally, the researchers identified that some amphiphiles possess electronic characteristics allowing them to “donate” electrons. By adding these electron-donating amphiphiles into the wearable materials, they created a fabric that was both comfortable and capable of generating electricity from friction caused by contact with skin or other surfaces.
“While the technology for harvesting static energy is fairly well-developed, there are still gaps for devices that can be worn for extended periods,” says Hsiao. “Our proof-of-concept tests showed that these amphiphile materials not only felt pleasant against the skin but could also generate up to 300 volts, which is impressive for such a small material.”
“Striking the right balance between the friction needed to generate energy and ensuring the wearer’s comfort is crucial in designing haptic technologies. Amphiphile chemistry provides an easy method to achieve this,” remarks Khan. “We are eager to further explore the potential of these materials, including how they can be integrated into current haptic devices, and we are open to collaborating with industry partners to identify new uses.”
The research paper, titled “Compressing Slippery Surface-Assembled Amphiphiles for Tunable Haptic Energy Harvesters,” is set to be published on September 15 in the journal Science Advances. The first author of the paper is Pallav Jani, who earned his Ph.D. from NC State. Co-authors include Kushal Yadav, another Ph.D. student at NC State, Maryanne Derkaloustian, and Charles Dhong from the University of Delaware, along with Hilmar Koerner, who heads the Polymer Matrix Composites Program at the Air Force Research Laboratory.
This research was supported by various institutions, including the Nonwovens Institute (project 18-224SB), the National Science Foundation (CAREER award number 2042635), the AFRL (Summer Faculty Fellowship Program), the Sloan Research Fellowship (grant number FG-2022-18336), the Dreyfus Foundation (grant number TC-22-038), the National Institutes of Health (grant R01EY032584-02), and the National Eye Institute (grant 5R01EY032584-03).
