Hydrogels with ultra-highly additive adjustable toughness under quasi-isochoric conditions

Abstract

Bioinspired smart hydrogels with additive-switchable mechanical properties are attracting increasing attention in recent years. However, most existing hydrogel systems suffer from limited stiffening amplitude and dramatic volume change upon response...

A double-well potential model for glass transition in a glassy hydrogel undergoing bi-stable interactions with water

“…Previous studies reported in ref. [13][14][15][16][17] revealed that there are two types of water molecules, i.e., the trapped water and free water, reacting with polymer macromolecules in the hydrogel. Fig.…”

“…To improve the mechanical properties of hydrogels, doublenetworks, 3 slide-ring crosslinking 10,11 and physical entanglement 12 have been employed. There were many studies to investigate the effects of gels' condensed states on the mechanical behavior of hydrogels, [13][14][15][16][17] including hydrogen bonds, 13 hydrophobic semi-permeable membranes, 14,15 and p bonds. 16 These condensed states enable water molecules to transit from bound water into free water after interacting with the polymer macromolecules.…”

“…A mechanical modulus of 50 MPa has been reportedly achieved for a glassy hydrogel with a water content of 50% at room temperature. [13][14][15] On the other hand, many studies had also been presented on viscoelastic and dynamic models of the soft matters. [18][19][20][21][22] For example, double-well potential models have been widely used to model the mechanical and thermodynamic behaviors of proteins, 23 hydrogen bonds, 24 soft media, 25 damped structures, 26,27 nanoscale structures 28 and fibrous gels.…”

“…Finally, the effectiveness of the proposed double-well model is verified using both finite element analysis (FEA) and experimental results of glassy hydrogels reported in the literature. [13][14][15]…”

A natural polymer-based hydrogel with shape controllability and high toughness and its application to efficient osteochondral regeneration

“…Although natural polymer-based hydrogels have received extensive attention in tissue engineering due to their abilities to infiltrate and regenerate the surrounding tissues, the contradiction between their mechanical support and molding controllability makes the preparation of the hydrogels with outstanding tissue regeneration effects challenging. 6,10,11 In general, cartilage withstands the compressive stress of several MPa and the nominal compressive modulus of 0.1-1.0 MPa during human movement. 12 In practical application, conventional scaffolds based on natural polymer-based hydrogels usually show insufficient mechanical strength and endurance under cyclic loading and abrasion conditions.…”