Scientists from Columbia University in the USA have developed a fabric with cooling capabilities inspired by the spectacular Madagascar Comet Moth
By Dafna Haim Langford.
The silkworms have a new competitor when it comes to the production of refreshing and shiny silk fibers - the Madagascar moon moth. The silk fibers spun by the Madagascar moth have a more 'lively' appearance compared to the silkworm moth, and even give a pleasant cooling sensation when in contact with the skin. In a recently published article, the development of artificial fibers that mimic the cooling sensation and the optical properties of the silk fibers produced by the Madagascar Comet Moth is described.
The engineers behind the development report that the silk fibers of the moth have a unique one-dimensional nanostructure. This structure dissipates heat at the same time as its ability to transmit light and image signals.
The leader of the Columbia University research, Professor Nanfang Yu, claims that the silk fibers of the moth are the best in nature in terms of protection from the sun's rays. The fibers transmit light signals from end to end and even light images from one fiber end to another. According to Professor Yu, the material imitating these fibers can be used in biomedical applications to create biodegradable materials, which will not cause a rejection reaction in the human body.
While the silkworms spin fibers that are cylindrical in shape, the fibers spun by the Madagascar moth appear metallic, and are lined along their length with a large number of tiny air spaces. These air spaces function as mirrors, which reflect about 70% of the light that hits them. To reach the light reflection level of one Madagascar silk fiber, at least ten layers of textile are needed. In addition, it turns out that the Madagascar silk fiber also reflects light in the infrared range - about 50% of sunlight.
These properties allow the fibers to block sunlight. The ability to reflect sunlight with such high efficiency is due to the chain of air bubbles along the fiber. The air bubbles scatter the light in such a way that it appears to be effectively directed along the length of the fiber. The researchers also claim that the way in which the Madagascar silk fibers transmit light is different from the way in which underwater optical fibers do so.
Inspired by the Madagascar silk fiber, Professor Yu and his team created synthetic fibers whose bubble density can reflect up to 93% of sunlight. They worked with two different starting materials - one biodegradable and the other a synthetic polymer.
According to the researchers, the new fibers can allow the production of textiles for clothing, very thin, but which will not become transparent when sweating. In addition, the new fibers enable the production of fabrics that not only reflect the sunlight, but allow the evaporation of sweat and the passage of air between the human body and the environment, to create a perfect conditioning experience.
