Chinese scientists have found that feeding silkworms a diet of graphene and carbon nanotubes leads these insects to spin what's being referred to as "super silk."

Scientists at Tsinghua University in Beijing said the "carbon-reinforced silk" produced by these silkworms is twice as strong as regular silk. To make carbon-reinforced silk, Yingying Zhang and her colleagues fed the silkworms mulberry leaves sprayed with aqueous solutions containing 0.2% by weight of either carbon nanotubes or graphene and then collected the silk after the worms spun their cocoons.

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The super silk is twice as strong as ordinary silk and can withstand at least 50 percent higher stress before breaking. It also conducts electricity unlike regular silk.

China is the world's leading producer of silk and source of silkworms. Graphene is a thin layer of pure carbon that's the thinnest compound known to man at one atom thick. It's the best conductor of electricity known.

The carbon atoms in a honeycomb lattice make graphene 200 times stronger than steel; more conductive than copper and as flexible as rubber. Layers of graphene stacked on top of each other form graphite.

"Silkworm silk is gaining significant attention from both the textile industry and research society because of its outstanding mechanical properties and lustrous appearance," said the paper describing the research in the journal Nano Letters. "The possibility of creating tougher silks attracts particular research interest.

"We report mechanically enhanced silk directly collected by feeding ... silkworms with single-walled carbon nanotubes and graphene. We found that parts of the fed carbon nanomaterials were incorporated into the as-spun silk fibers."

The results of these tests suggest production of the super-strong silk might be scaled up. The method described in the study provides an easy way to produce high-strength silk fibers on a large scale. 

The super silk produced by the silkworms could be used in applications such as ecofriendly wearable electronics; durable protective fabrics and biodegradable medical implants.

Tagssilkworms, Graphene, Carbon nanotubes, Tsinghua University, silk, super silk, carbon-reinforced silk, Yingying Zhang