Soft materials implanted in the body are vulnerable, as they are continuously subject to repeated and prolonged deformation in a corrosive environment (e.g., water, pH, salt, enzymes, chemicals, temperature). These multiple attacks are typically concurrent and the resulting material behaviors are often complicated. We study the mechanics and chemistry coupling of soft materials, in particular, the fracture process of mechanochemistry. We have studied how the presence of water accelerates crack propagation. For example, a widely-used biocompatible PDMS elastomer suffers stress-assisted hydrolysis and the crack growth in water is orders of magnitude faster than that in ambient air; We have also tested the mechanochemistry in a biodegradable PLA plastics and showed that the crack velocity is insensitive to load but is sensitive to humidity and pH. These findings will aid the development of degradable or non-degradable soft materials for implantation.

Relevant papers on this topic.

• Yang, X.#, Yang, J.#, Chen, L. and Suo, Z., 2019. Hydrolytic crack in a rubbery network. Extreme Mechanics Letters, p.100531.
• Yang, X., Steck, J., Yang, J., Wang, Y. and Suo, Z., 2021. Degradable plastics are vulnerable to cracks. Engineering, 7(5), pp.624-629.