Mimicking a cell´s mechanical behavior for strain-stiffening materials with advanced propertiesWednesday (19.06.2019) 11:45 - 12:00
As known for example from airplane wings and velcro, mimicing nature is a way of overcoming obstacles in several fields of science by adapting biological meachnisms. We also adapted a mechanical property intrinsic to cells for the development of a strain-stiffening material. “Strain stiffening” refers to the phenomenon where the stiffness of a material increases when it is strained. Such materials are already used in applications as diverse as leaf-spring suspensions in cars, or in shock absorbing layers in protective clothing, and perform their task very well. However, strain-stiffening materials also come with downsides that prevent their use for other tasks, namely: limited choice of underlying materials, rate dependent stiffening, irreversibility of the effect in some cases, as well as limitation of the effect to stiffening by material compression. To come up with a solution that neutralizes the listed disadvantages we chose the above mentioned biomimetic approach: imitating the capability of cells to stiffen in response to an external force through the linking up of biopolymer fibers inside the cell. We used this characteristic to develop a structured material which harbors none of the downsides mentioned above. Our material has a specially designed structure so that deformation leads to a reversible interconnection of internal surfaces and thus to stiffening. By adjusting the geometry of the structure of a given elastic material, initial stiffness, point of stiffening and final stiffness can be customized towards a certain application. This opens a wide field of applications ranging from orthotics over soft robotics towards artificial blood vessels.