AsianScientist (Jul. 21, 2015) – Researchers have designed and synthesized an exceptionally strong hydrogel, using molecularly engineered dual-crosslinking. Their results have been published in Advanced Materials.
Hydrogels are ‘soft and wet’ materials that have been widely applied in sensing, drug delivery, actuation, tissue engineering, etc. Hydrogels possess a degree of flexibility very similar to natural tissue, which make them the ideal alternate materials for artificial joints and best substrate materials for the development of muscle-like actuators.
However, hydrogels usually do not have enough mechanical strength due to their intrinsic structural inhomogeneity or lack of effective energy dissipation mechanisms. Besides ultrahigh strength, good self-recovery property of a hydrogel at room temperature is also important for fatigue resistance and extending its service life. However, existing hydrogels do not have self-recovery properties or their self-recovery takes a long time.
In the present study, a team led by Professor Zhou Feng from the Lanzhou Institute of Chemical Physics of the Chinese Academy of Sciences developed a strong yet stretchy hydrogel.
They combined both covalent crosslinking and multivalency ion pairing of Fe3+–acrylic acid coordination to form a dual-crosslinked hydrogel. The ion paring interaction acts as the special dynamic junction. When an external load was applied, the coordination bond served as the reversible sacrificial bonds, rupturing to dissipate the energy.
The dual-crosslinked hydrogel had ultrahigh mechanical strength, excellent elongation, and good self-recovery properties. The optimal hydrogel achieves a tensile stress of ca.6 MPa at a large elongation ratio (>seven times), a toughness of 27 MJm3, and a stiffness of ca.2 MPa.
Moreover, the mechanical property of the hydrogel can be easily tuned within a wide range for different applications by varying the concentration of acrylic acid or Fe3+–loading solution and so the number of ionic interaction.
The synthetic method is very simple, and the raw materials are cheap and suitable for a large-scale preparation.
The article can be found at: Lin et al. (2015) Molecularly Engineered Dual-Crosslinked Hydrogel with Ultrahigh Mechanical Strength, Toughness, and Good Self-Recovery.
———
Source: Chinese Academy of Sciences.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
