Apr 22 2019
A person’s expectations are constantly changing on what they wear: cozy, beautiful, and nowadays, smart.
A new research published in the international journal Advanced Functional Materials says that researchers using silkworm silk have created a smart textile that can contract and stretch automatically when humidity varies.
According to the research, the sleeves created from such smart textile can contract as much as 45% in the vertical direction when exposed to sweat or moisture and then recover to its original length when the environment becomes dry.
The key to the feature is a fiber artificial muscle created by scientists from the Tianjin-based Nankai University.
The fiber artificial muscles denote materials that imitate natural muscles and can reversibly contract, expand, or rotate within one component because of an external stimulus, such as electricity, moisture, temperature, and light.
In this research, the artificial muscle was composed of silkworm silk because the natural fiber is inexpensive, comfortable and absorbs water well.
Liu Zunfeng, the main researcher, said that the research was inspired by the mechanism of reversible volume expansion of silk fiber. After water molecules are absorbed by silk protein, the fiber volume would increase, and its porosity would differ.
The fiber volume changes and structural alteration after water absorption and desorption will result in reversible contraction, expansion and rotation reactions, signifying that silk would be a potential option for moisture-responsive smart textiles.
Furthermore, mature processing approaches of silk, such as dyeing, degumming, and thermal setting, guarantee the widespread applicability of silk muscle.
The silk muscle can alter porosity by adapting to sweat, humidity, rain, and temperature.
"When you are sweating, you may find your clothes shrink. But after the sweat dries, the material will grow longer to keep you warm," said Liu.
Although scientists have not carried out experiments on humans, they believed that the clothing length changes would not cause any uneasiness to the skin.
Liu said that the silk muscle would garner wide-ranging prospects.
"Because silk is largely abundant and cost-effective, the silk muscle will open a path to more possibilities in textiles, medicine, and soft robotics," he said.