Silkworms eat carbon nanomaterials and spit out super-strong silk

After researchers at Tsinghua University fed graphene or single-walled carbon nanotubes to silkworm babies, the “silk” they spit out became stronger and stronger. According to a report on the Scientific American magazine website on the 10th, this carbon-reinforced yarn can be used in durable protective fabrics, biodegradable medical implants and environmentally friendly wearable electronic devices.

To make carbon-reinforced silk, Zhang Yingying of Tsinghua University and colleagues directly sprayed an aqueous solution containing carbon nanotubes or graphene (0.2% of the total weight) into the mulberry leaves eaten by silkworm larvae, and then collected them after the larvae spun silk and formed cocoons. silk.

According to reports, this method of directly feeding a carbon-containing water solution is simpler and more environmentally friendly than the method of directly processing cocooned silk. More importantly, the toughness of carbon-reinforced wires to resist external force damage is doubled, and the stress they can withstand is at least 50% higher. The research team heated the silk to 1050 degrees Celsius and further studied the conductivity and structure of the carbonized silk protein fibers. Raman spectroscopy and electron microscopy imaging showed that the crystal structure of carbon-reinforced filaments incorporated with nanomaterials was more ordered.

Shen Qing, a polymer chemist at Donghua University in Shanghai, used 30-nanometer multi-walled carbon nanotubes to create new silk fibers in 2014. He believes that the 1-2 nanometer single-walled carbon nanotube material used by Zhang Yingying’s team is “more suitable for integration into the silk protein crystal structure.” “.

Materials scientist Zhang Yaopeng, who has produced silk resistant to ultraviolet degradation by feeding nano-titanium dioxide to silkworm larvae, said that the Tsinghua team “provided a simple method for large-scale production of high-strength silk fibers, and its excellent conductivity makes it more suitable for applications in embedded intelligence.” in textiles and sensors that can read neural signals.”