Spider silk is a protein material that exhibits extraordinary and nontrivial properties such as the ability to soften, decrease its length by up to ∼60%, and twist upon exposure to high humidity. These counter-intuitive phenomena stem from a transition of a highly oriented glassy phase to a disoriented rubbery phase. In our recent works we derive models that explain the origin of these behaviors. The insights from this work motivate the development of novel biomimetic materials.

Thermally activated structures can be used in various fields such as soft robotics, smart materials, actuators, and self-assembly. The design of such structures requires a comprehensive understanding of the relations between geometry, material properties, structure composition, and material response to temperature. In our recent work we derive a model that can be used as a guideline and an inverse design tool for the selection of materials and geometries for thermally-activated shape-morphing lattice-based structures that are capable of achieving multiple shape-shifts with a single stimulus.

How do we induce twist in tubes without applying a torque? In nature, such a deformation mode is enabled by material anisotropy. In our new work, we show that isotropic bi-layer tubes with twist incompatible layers can twist upon inflation and extension. Interestingly, the direction of twist can spontaneously reverse as the load increases, as shown in this video!

Mechanics is fun! Can you figure out how a single toothpick can carry the weight of a water bottle?