Researchers from ETH Zurich, led by Professor Rafael Libanori, have developed a novel type of adaptive hydrogel that autonomously stiffens in response to chemical stimuli. The team, including Natascha Gray, Zoe Grämiger, and André R. Studart, has created a material that could have significant implications for the energy sector, particularly in soft robotics and biomedical devices used in energy applications.
The study, published in the journal Nature Communications, focuses on creating adaptive materials that can respond to external stimuli without requiring external energy inputs. The researchers embedded glucose oxidase within a double-network hydrogel composed of polyacrylamide and alginate. This hydrogel contains Ca(EDTA)2- complexes, which make the alginate network responsive to pH changes through a competitive calcium binding mechanism.
When a chemical stimulus activates the enzymatic reaction, it generates chemical waves that propagate through the hydrogel. These waves drive spatiotemporal mechanical transitions, increasing the material’s stiffness by up to 2.1-fold. The key innovation here is the direct enzymatic modulation of the hydrogel’s crosslinking density, which allows the material to autonomously convert localized chemical inputs into system-wide mechanical outputs.
For the energy sector, this research could lead to the development of intelligent materials that can adapt to changing environmental conditions. For instance, these adaptive hydrogels could be used in soft robotics for energy exploration or maintenance, where the ability to autonomously respond to chemical stimuli could enhance the robots’ functionality and durability. Additionally, in biomedical applications related to energy, such as drug delivery systems or implantable devices, these materials could improve performance by adapting to the body’s chemical environment.
The practical applications of this research are still in the early stages, but the potential for creating materials that can autonomously respond to their environment is a significant step forward. As the energy sector continues to seek innovative solutions for efficiency and sustainability, adaptive materials like these could play a crucial role in future technologies.
Source: Gray, N., Grämiger, Z., Studart, A.R., & Libanori, R. (2023). Adaptive hydrogels with spatiotemporal stiffening using pH-modulating enzymes. Nature Communications.
This article is based on research available at arXiv.