Cotton fiber with enhanced conductivity to generate electricity

A Washington State University breakthrough combines the flexibility of cotton with the electrical conductivity of polymers, paving the way for advanced wearable electronic textiles.

A single fiber developed at Washington State University has the flexibility of cotton and the electrical conductivity of a polymer called polyaniline.

The newly developed material showed great potential as a wearable electronic textile. WSU researchers tested the fibers with a system that powers LED lights and a system that senses ammonia gas, and detailed their results in the journal Nature. carbohydrate polymer.

Microscopic image of the newly developed fiber. It shows a parallel mix, with one side containing cotton and the other side a polyanaline polymer that can conduct electrical current.Credit: Washington State University

“One fiber is divided into two sections. One section is traditional cotton, flexible and strong enough for everyday use, and the other side is a conductive material,” says WSU Textile Research. said Hang Liu, a researcher and corresponding author of the study. “Cotton can support conductive materials that can provide the required functionality.”

Potential applications in wearable technology

Although further development is required, the idea is to incorporate such fibers into apparel as sensor patches with flexible circuitry. These patches could become part of the uniforms of firefighters, soldiers, and workers who work with chemicals to detect hazardous exposures. Other applications include health monitoring and exercise shirts with features beyond today’s fitness monitors.

“We have some smart wearable products like smartwatches that can track people’s movements and people’s vital signs, but in the future we hope that everyday wear will also have these features. “We are doing so,” Liu said. “Fashion is more than just colors and styles, as many people think. Fashion is a science.”

Han Liu, a textile researcher at Washington State University.Credit: Washington State University Dean Hare

Technical challenges and solutions

In this study, the WSU team worked to overcome the challenge of blending conductive polymers with cotton cellulose. Polymers are substances with very large molecules that have repeating patterns. In this case, the researchers used polyaniline, also known as PANI, a synthetic polymer with conductive properties that is already used in applications such as printed circuit board manufacturing.

Although polyaniline is inherently conductive, it is brittle and cannot be made into textile fibers on its own. To solve this, WSU researchers dissolved cotton cellulose from recycled T-shirts in a solution and a conductive polymer in another solution. He then combined the two solutions side by side and extruded the material to create a single fiber.

Han Liu, a textile researcher at Washington State University, shows a microscopic image of the newly developed fiber, showing a side-by-side mixture containing cotton on one side and a polyanaline polymer that can conduct electrical current on the other side. We are confirming that there is.Credit: Washington State University Dean Hare

The results showed good interfacial bonding. This means that the molecules of different materials stay together even when stretched or bent.

Achieving the right mixture at the cotton cellulose and polyaniline interface required a delicate balance, Liu said.

“We’ve made these two solutions work so that when the cotton and conductive polymer come in contact with each other, they mix to some extent in a glue-like state. But don’t mix too much; don’t do that. And it becomes less conductive,” she said.

Reference: “Novel structural design of cellulose-based conductive composite fibers for wearable electronic textiles” Wangcheng Liu, Hang Liu, Zihui Zhao, Dan Liang, Wei-Hong Zhong, Jinwen Zhang, August 18, 2023. carbohydrate polymer.
DOI: 10.1016/j.carbpol.2023.121308

In addition to lead author Wangcheng Liu, WSU authors of the study also include Zihui Zhao, Dan Liang, Wei-Hong Zhong, and Jinwen Zhang. This research received support from the National Science Foundation and the Walmart Foundation Project.