An Insight into Skeletal Networks Analysis for Smart Hydrogels

Abstract

Hydrogels are 3D cross-linked polymer networks. Benefiting from the flexible designs and reasonable constructions of these networks, a large number of smart hydrogels with response characteristics to specific stimuli have received widespread attention and developed rapidly. The skeletal networks composed of the skeletal polymer chains and effectual cross-links are the soul of such soft materials, and the response behaviors fundamentally depend on the dynamic characteristics of skeletal networks. Herein, the novel concepts of skeletal networks analysis to describe, understand, and guide the advanced designs and applications of smart hydrogels are proposed. Representative glucose-sensitive hydrogels and DNA-based smart hydrogels are reviewed to demonstrate the principle of skeletal networks analysis and clarify its practical guidance. Summarizing and classifying the characterizations and conversions of skeletal networks dynamics based on different response mechanisms provides a realistic solution. On this basis, advanced applications of smart hydrogels guided by skeletal networks dynamics including biochemical detection, cell mechanics sensing, drug delivery systems, and dynamic complex soft materials are typically reviewed. The skeletal networks analysis for smart hydrogels is of great significance for understanding the microstructures of hydrogels and guiding the designs of soft materials and their smart applications in the fields of analytical science and advanced materials.

Mussel Inspired Trigger‐Detachable Adhesive Hydrogel

“…Some researches about double networks were consistent with it. [38][39][40] The following rheological measurement was performed for getting insight into the hydrogel thixotropy (Figure 1c). The storage modulus (G′) indicated the quantity of stored energy in the system, it would characterize the solid-liked property of the hydrogel; the loss modulus (G″) presented the quantity of dissipated energy in the network, it would characterize the liquidliked property of the hydrogel.…”

Recent advances in flexible and soft gel-based pressure sensors

“…Gels are flexible and soft materials consisting of three-dimensional (3D) crosslinked polymer networks (solid content) and numerous internal open pores filled with either solvents (liquid content, e.g., hydrogels [30][31][32] and ionogels [33][34][35] ) or air (gas content, e.g., aerogels [36][37][38] ) [39][40][41] . Due to the framework of strong bonding between polymer chains and the redundant space of internal open pores for deformation, hydrogels and ionogels exhibit an intrinsic nature of superior flexibility and stretchability.…”

“…Copyright 2022, American Chemical Society)). Six primary application directions, namely, living things, healthcare, prosthesis, human-machine interactions, electronic skin, and tissue engineering, are also illustrated (reproduced with permission [39] .…”

Double-Network Luminescent Films Constructed Using Sulfur Quantum Dots and Lanthanide Complexes

“…With the rapid development of intelligence science, self-healing, tough, and stretchable materials have become highly desirable and have been attracting increasing attention for their promising application in stretchable sensors, health monitors, surface protection coatings, and so on. − Recently, great progresses have been achieved in developing self-healing hydrogels based on dynamic noncovalent interactions (hydrogen bonds, electrostatic interactions, metal coordination bonds, supramolecular interactions, and hydrophobic interactions), motivating various scientific and engineering innovations in the field of flexible devices. − However, the practical long-term application of synthetic hydrogels is susceptible due to their internal structural defects and fatigue fracture, even though their toughness could be improved by introducing multiple interactions. − On the one hand, lots of water molecules in the hydrogels can disturb the reconnection of dynamic bonds, impeding their further self-healing behavior . On the other hand, it is difficult to simultaneously enhance the mechanical strength and optimize the healing efficiency because these characteristics are contradictory. , Except for the above-mentioned two defects, endowing self-healing materials with photoluminescent (PL) property can promote and extend their applications under more complex working conditions, such as biosensors and optical switch. − …”