Natural materials are adaptive with intriguing mechanical properties such as strain-stiffening, high damping, and stimuli-responsive actuation under ambient conditions, which are evolutionarily derived to adapt to variable environments. Such adaptabilities are highly desirable for advanced smart materials in soft robots and bionic applications yet rarely achieved all in one synthetic material.
Spider silk is renowned for its fascinating adaptability such as strain-stiffening, damping-but-elastic, torsional dampening and supercontraction, which have inspired intense efforts in design and synthesis of biomimetic functional fibers. Strain-adaptive stiffening is crucial for spider silk in maintaining the web’s structural integrity. Its high damping capacity at varying deformation rate ensures the secure capture of preys flying at high velocity without causing rebound. Noteworthily, the spider silk can contract up to ~50% in response to high humidity or water (i.e., supercontraction), restoring the configuration of spider webs from large deformations and developing an additional tension to keep the web taut.
Inspired by the molecular chemistry and structure of spider silk, Prof. Dr. Siya Huang’s team from the Institute for Advanced Study at Shenzhen University developed a structurally heterogeneous supramolecular network with all-round adaptabilities by evaporation-induced self-assembly of hydrogen-bonded macromolecules. The supramolecular network consists of both hard (crystallites) and soft (amorphous) phases with dynamic hydrogen bonds, exhibiting strong strain, time and hydration dependency with adaptive mechanical and structural responses to varying strain, deformation rate as well as moisture. Through multifunctional crosslinking, the network exhibits silk-like attributes with an extensibility of >130%, intense strain-stiffening (6-fold modulus enhancement), high damping capacity (>80%) over a wide range of strain rate, and moisture-triggered large supercontraction (contraction ratio of >50%). Artificial materials with such combined adaptiveness under bio-benign conditions are promising for applications in biomimetic and biomedical fields.
This work entitled "Spider-Silk-Inspired Heterogeneous Supramolecular Network with Strain-Stiffening, High Damping Capacity, and Supercontraction" has been published inAdvanced Functional Materialsrecently. Boyan Du, a master student of the Institute for Advanced Study at Shenzhen University is the first author. This work was supported by the National Natural Science Foundation of China and the Basic and Applied Basic Research Foundation of Guangdong Province.
原文链接：https://doi.org/10.1002/adfm.202306071
