Jian Ping Gong

 Faculty of Advanced Life Science, WPI-ICReDD, Hokkaido University

WINSTON CHEN LECTURE

Biological tissues are dynamic, open systems in which structural transformations to adapt to the surrounding environment are constantly occurring through metabolic processes. For example, skeletal muscles hypertrophy and strengthen due to repeated mechanical exercise. The exertion destroys the fibril structure, whereas the nutrition (amino acids) supply and constructive chemical reactions grows new muscle. By contrast, synthetic materials are static, closed systems, with no structural reconstruction and substance exchange with surroundings. Usually, repetitive mechanical loading leads to damage and even failure of materials.

Recently, we present a strategy for creating metabolic-like hydrogels that self-grow and strengthen by repetitive mechanical stimuli. We show that the double-network hydrogels exhibit sustained strength increase along with size increase under repetitive loading in monomer (nutrition) solution. This metabolic-like phenomenon of double network hydrogels is through a repetitive structural destruction and reconstruction of the brittle network by mechanochemical transduction.  The unique architecture of double network hydrogels —where a highly pre-stretched, brittle first network is embedded within a more flexible second network—enables the efficient transmission of macroscopic stress to individual polymer chains and trigger chemical bond scission, without causing material failure. Leveraging this intrinsic mechanochemical responsiveness, we have developed DN-based materials capable of real-time damage sensing, adaptive strengthening, and autonomous repair through mechanoradical polymerization from the ruptured bonds. This mechanism also enables double network materials to undergo force-activated morphogenesis and surface patterning. Such force-induced structural growth contributes to the development of adaptive and self-growing materials, holding the potential for application to biomimetic "living materials".

Bio:

Jian Ping Gong is a distinguished professor of Hokkaido University, Japan. She graduated from Zhejiang University, and received Doctor of Engineering at Tokyo Institute of Technology. She joined the faculty at Hokkaido University in 1993. She received many awards, including Wiley Polymer Science Award (2001), the Award of the Society of Polymer Science, Japan (2006), the DSM Materials Sciences Award (2014), the Chemical Society of Japan (CSJ) Award in 2022, and the APS 2023 Polymer Physics Prize. She works on tough double network hydrogels, self-healing hydrogels, hydrogel friction and adhesion, hydrogel composites. Recently, her interest is on self-growing hydrogels based on mechanochemistry.