New Material: Research Finds A Material Technology With Strong Adhesion And Tensile Strength Of Fiber In Advance

According to the latest issue of Advanced Functional Materials, the team of Tufts University in the United States, inspired by the sci-fi scene of Spider Man in which the wrist shoots the spider web, invented a technology that can emit spider silk.

This technology uses silk fibroin extracted from the cocoon of the silkworm moth, which is decomposed into basic protein components after boiling treatment. When this silk fibroin solution is extruded through a fine needle and mixed with a specific additive, it will solidify rapidly after contacting air, forming a fiber with strong adhesion and tensile strength.

In an earlier experiment, the research team accidentally found that when acetone was used to clean glassware, a mesh substance appeared at the bottom. This accidental phenomenon helped solve some engineering challenges encountered in the process of copying spider silk. Silk fibroin solution will slowly solidify into semi-solid hydrogel when contacting with organic solvents such as ethanol or acetone, but the curing process becomes very fast after adding dopamine as the adhesive component. The mechanism of action of dopamine is similar to the chemical reaction used in barnacles of marine organisms, which can promote the firm adhesion of fibers to various surfaces.

In order to further optimize fiber performance, the team added dopamine to silk fibroin solution, which helps to accelerate the process of liquid to solid transformation. Injected through a coaxial needle, the filament solution is surrounded by a layer of acetone, which immediately causes coagulation in the air. With the evaporation of acetone, the formed fiber can immediately adhere to the contact object. In addition, they also introduced chitosan (derived from insect exoskeleton) to increase the tensile strength of the fiber to 200 times the original, and used borate buffer to enhance the adhesion by about 18 times.

The final fibers have a wide range of diameters, ranging from thinner than human hair to nearly half a millimeter, depending on the size of the needle used. The fiber produced by the device shows an amazing load-bearing capacity, and can even lift an object 80 times more than its own weight. In order to verify this, the team successfully demonstrated the use of this fiber to lift cocoons, steel bolts, laboratory test tubes floating on the water, scalpels and wood blocks partially buried in the sand from a distance of about 12 cm.