Method for enhancing mechanical strength of hydrogel based on masking strategy

Abstract

The invention discloses a method for enhancing the mechanical strength of hydrogel based on a masking strategy. The method includes: based on a polyvinyl alcohol-polyacrylic acid (PVA-PAA) hydrogel precursor a ligand with a masking effect is added into a metal solution in advance by means of the masking strategy, so that by temporarily masking the reaction activity of the metal complex, the fast and uniform penetration into a PVA-PAA system is facilitated; then, through the bridging effect of masking ligands, under the alkaline condition, the size and charge of the metal complex are properly increased, the metal complex and PVA-PAA functional group carboxyl form an efficient and stable coordination effect, the structural stability of a PVA-PAA hydrogel three-dimensional network is furtherimproved, and therefore the mechanical strength of the gel system is greatly enhanced. According to the invention, a masking method is applied to the field of hydrogel synthesis for the first time, and a simple, convenient and feasible new way for synthesizing a high-strength hydrogel structure material is opened up.

Description

technical field [0001] The invention belongs to the field of functional materials, and in particular relates to a method for enhancing the mechanical strength of hydrogel based on a masking strategy. Background technique [0002] As a new type of flexible material, hydrogel has been widely used in the fields of wearable devices, flexible devices and drug sustained release. However, traditional hydrogels suffer from low mechanical strength and poor toughness due to the heterogeneity of their intrinsic structure or insufficient effective energy dissipation mechanism, which limits their application as structural materials in flexible electronics, biomedicine, environment, tissue engineering and other fields. Based on the energy dissipation mechanism of reversible destruction and reconstruction of dynamic coordination bonds, cross-linking by metal ions (MI) to further enhance the mechanical strength of hydrogels has been proven to be an effective method. [0003] Soaking in MI ...

AI Technical Summary

Problems solved by technology

In the traditional MI solution immersion method, due to Cl - , NO 3 - or H 2 The weak coordination field effect of O makes the functional groups on the surface of the hydrogel (mainly carboxyl groups, strong field ligands) quickly attack the inner boundary of the complex (fast recognition), thereby forming a dense "shell" on the surface of the hydrogel. layer", which affects the further penetration of MI, resulting in over-bonding and uneven bonding on the surface, which is manifested in the uneven mechanical strength of MI-HG, thus weakening the overall ductility of the material

Furthermore, even small molecules [Fe(H 2 O)] 3+ And so on, because the molecular size and charge are difficult to increase, the binding efficiency between MI and functional groups is poor, that is, the metal complexes exist in the hydrogel in a free state, adsorption or single-point binding unstable form, resulting in MI- The mechanical strength of HG is not significantly enhanced, which limits its application in many fields such as medical stents and soft mechanical parts

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