An international group of scientists, led by MIT professor Zhao Qin, was interested in the flexible translucent membrane in the tail of lobsters. It has a unique structure that can be used in modern armor technology.
Scientists have found that this membrane is 90% water and 10% chitin, a fibrous material found in insect shells and exoskeletons. The lobster membrane, in fact, turned out to be a tough natural hydrogel, which outstrips animal skins and even natural rubber in terms of rigidity. At the same time, in terms of strength, it corresponds to industrial rubber composites.
In addition, in the course of research, it was found that the membrane becomes more rigid when stretched. A typical example: when a membrane is cut with a scalpel, even up to half its thickness, it does not lose its ability to stretch. According to scientists, this would be impossible for rubber composites.
The membrane owes these qualities to its microstructure, which is somewhat reminiscent of plywood. So, a layer about a quarter of a millimeter thick consists of tens of thousands of layers of chitinous fibers. Moreover, all fibers in each layer are oriented at the same angle - 36 degrees relative to the next upper layer.
To test the properties of such a material, scientists tested the strength of an artificial hydrogel, in which chitin fibers were oriented relative to each other in a random order. When stretched, these fibers broke.
The research results give hope for the creation of more flexible body armor, which is especially important for the protection of the shins and elbow joints. The new material will also find application in soft robotics and tissue engineering.