Methyl matters: An autonomic rapid self-healing supramolecular poly(N-methacryloyl glycinamide) hydrogel

Publication date: 22 September 2017
Source:Polymer, Volume 126
Author(s): Yalei Ren, Yinyu Zhang, Wenhui Sun, Fei Gao, Weigui Fu, Peiyi Wu, Wenguang Liu
Poly(N-acryloyl glycinamide) (PNAGA) with a protein-like thermoresponsive gelation behavior in water has been developed as a high strength self-healable supramolecular polymer(SP) hydrogels recently. However, harsh conditions, such as high temperature treatment and long waiting time, were required for achieving the complete healing due to strong dual amide hydrogen bonding interactions. In this study, to create an autonomic rapid self-healing SP hydrogel, we deliberately introduced a methyl into the opposite side to dual amide to synthesize N-methacryloyl glycinamide (MNAGA) monomer. Rheological analysis, dynamic light scattering(DLS), Fourier transform infrared (FTIR) spectroscopy, and Gaussian calculation revealed that one substitution methyl caused a considerable perturbation to the hydrogen bonding interaction, thus leading to the increased starting gelling concentration and pronounced decrease in mechanical properties of PMNAGA hydrogel compared to PNAGA hydrogel. The PMNAGA hydrogel was shown to exhibit rapid autonomic reparability without any external intervention, and dynamic swelling measurement indicated this PMNAGA hydrogel could evolve from permanent to transient network due to the metastable hydrogen bonding crosslinkage, depending on its environmental temperature. This intriguing robust, autonomous healing and autolytic PMNAGA hydrogel holds great potential as a short-term embolic agent for blocking blood vessel and artificial tears for moistening eyes.

Graphical abstract

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