Many biological systems are made of swollen rubber-like protein networks. Examples include spider silk and resilin (commonly found in insects). These networks exhibit many fascinating behaviors upon hydration such as a significant softening, contraction, and twist. Our group aims to better understand the relations between the micro-structure and the macroscopic response of such biological hydrogels and derive tools that enable the design of bio-inspired polymeric materials.
Humidity-driven supercontraction and twist in spider silk
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 behaviors are the result of a transition from a highly oriented glassy phase to a disoriented rubbery phase. Our new work presents a model that explains the origins of this phenomena. The insights from this work motivate the development of novel biomimetic materials.
Check out our work here:
The underlying mechanisms behind the hydration-induced and mechanical response of spider silk
On the origin of supercontraction in spider silk
Biological polymer networks that experience significant softening under hydration
The fabrication of synthetic materials with unique properties is often inspired by observations from nature.
Recent experimental evidence showed that the elastic protein network resilin, which is commonly found in insects, is capable of experiencing a significant softening of several orders of magnitude upon water uptake. We recall that the stiffness of “classical” polymers, such as rubber, modestly decreases as swelling occurs.
What are the mechanisms behind the swelling-induced response of the bio-polymer network resilin? We answered that question in our new work.