Thermoresponsive nanocomposite hydrogels with high mechanical strength and toughness based on a dual crosslinking strategy

Gu, Heng; Wang, Gang; Cao, Xiaodong

doi:10.1002/app.51509

Cited by 8 publications

(5 citation statements)

References 41 publications

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“…Figure 11 shows that collapse of PNIPAm gel at room temperature (which leads to a strong enhancement of its mechanical properties) occurs when the mole fraction of salts equals 0.15 M. This conclusion is in accord with observations on a similar gel [70], revealing that the growth of mole fraction of FeCl 3 salt above 0.15 M (up to 0.6 M) does not induce changes in its toughness. Equilibrium swelling diagrams on PNIPAAm gel in aqueous solutions of CaCl 2 are reported in Figure 12.…”

Section: Numerical Analysissupporting

confidence: 84%

Swelling of Thermo-Responsive Gels in Aqueous Solutions of Salts: A Predictive Model

Drozdov

Christiansen

2022

Molecules

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The equilibrium degree of swelling of thermo-responsive (TR) gels is strongly affected by the presence of ions in an aqueous solution. This phenomenon plays an important role in (i) the synthesis of multi-stimuli-responsive gels for soft robotics, where extraordinary strength and toughness are reached by soaking of a gel in solutions of multivalent ions, and (ii) the preparation of hybrid gels with interpenetrating networks formed by covalently cross-linked synthetic chains and ionically cross-linked biopolymer chains. A model is developed for equilibrium swelling of a TR gel in aqueous solutions of salts at various temperatures T below and above the critical temperature at which collapse of the gel occurs. An advantage of the model is that it involves a a small (compared with conventional relations) number of material constants and allows the critical temperature to be determined explicitly. Its ability (i) to describe equilibrium swelling diagrams on poly(N-isopropylacrylamide) gels in aqueous solutions of mono- and multivalent salts and (ii) to predict the influence of volume fraction of salt on the critical temperature is confirmed by comparison of observations with results of numerical simulation.

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Section: Numerical Analysissupporting

confidence: 84%

Swelling of Thermo-Responsive Gels in Aqueous Solutions of Salts: A Predictive Model

Drozdov

Christiansen

2022

Molecules

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“…Gu et al put forward a method for preparing double cross-linked poly(N-isopropyl acrylamide) hydrogels with excellent mechanical properties. [204] N-isopropyl acrylamide and sodium acrylate form a simple copolymer, and then -COOgroups on side chains of copolymer form an ionic coordination bond with multivalent metal cations to complete the secondary physical cross-linking. [214] Copyright 2020, Elsevier B. V. B) Schematic diagram of a multi-purpose platform for sensing and power collection / storage of CS/CGG hydrogels.…”

Section: Double Cross-linkingmentioning

confidence: 99%

An Overview on Recent Progress of the Hydrogels: From Material Resources, Properties, to Functional Applications

Wang

Yang

et al. 2022

Macromol. Rapid Commun.

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Hydrogels, as the most typical elastomer materials with three-dimensional (3D) network structures, have attracted wide attention owing to their outstanding features in fields of sensitive stimulus response, low surface friction coefficient, good flexibility, and bio-compatibility. Because of numerous fresh polymer materials (or polymerization monomers), hydrogels with various structure diversities and excellent properties are emerging, and the development of hydrogels is very vigorous over the past decade. This review focuses on state-of-the-art advances, systematically reviews the recent progress on construction of novel hydrogels utilized several kinds of typical polymerization monomers, and explores the main chemical and physical cross-linking methods to develop the diversity of hydrogels. Following the aspects mentioned above, the classification and emerging applications of hydrogels, such as pH response, ionic response, electrical response, thermal response, biomolecular response, and gas response, are extensively summarized. Finally, this review is done with the promises and challenges for the future evolution of hydrogels and their biological applications.

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“…Strategies such as construction of comb-type architectures, [17] pore channels, [18] and nanocomposite structures [19] have been proposed to improve the response rate of PNIPAM hydrogels. On the other hand, tough PNIPAM hydrogels via strategies including composition of nanogels, [20] formation of interpenetrating polymer network, [21] double network, [22] and slide ring structure [23] have been developed. However, these approaches could compromise the stimulus sensitivity as well as the equilibrium swelling rate of the hydrogel.…”

Section: Introductionmentioning

confidence: 99%

Microgel‐Crosslinked Thermo‐Responsive Hydrogel Actuators with High Mechanical Properties and Rapid Response

Yang,

Xiao,

et al. 2024

Macromol. Rapid Commun.

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Smart hydrogels responsive to external stimuli are promising for various applications such as soft robotics and smart devices. High mechanical strength and fast response rate are particularly important for the construction of hydrogel actuators. Herein, tough hydrogels with rapid response rates were synthesized using vinyl‐functionalized poly(N‐isopropylacrylamide) (PNIPAM) microgels as macro‐crosslinkers and N‐isopropylacrylamide as monomers. The compression strength of the obtained PNIPAM hydrogels was up to 7.13 MPa. The response rate of the microgel‐crosslinked hydrogels was significantly enhanced compared with conventional chemically crosslinked PNIPAM hydrogels. The mechanical strength and response rate of hydrogels can be adjusted by varying the proportion of monomers and crosslinkers. The lower critical solution temperature (LCST) of the PNIPAM hydrogels could be tuned by copolymerizing with ionic monomer sodium methacrylate. Thermo‐responsive bilayer hydrogels were fabricated using PINPAM hydrogels with different LCSTs via a layer‐by‐layer method. The thermo‐responsive fast swelling and shrinking properties of the two layers endow the bilayer hydrogel with anisotropic structures and asymmetric response characteristics, allowing the hydrogel to respond rapidly. The bilayer hydrogels have been fabricated into clamps to grab small objects and flowers that mimicked the closure of petals, and it shows great application prospects in the field of actuators.This article is protected by copyright. All rights reserved

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Thermoresponsive nanocomposite hydrogels with high mechanical strength and toughness based on a dual crosslinking strategy

Cited by 8 publications

References 41 publications

Swelling of Thermo-Responsive Gels in Aqueous Solutions of Salts: A Predictive Model

Swelling of Thermo-Responsive Gels in Aqueous Solutions of Salts: A Predictive Model

An Overview on Recent Progress of the Hydrogels: From Material Resources, Properties, to Functional Applications

Microgel‐Crosslinked Thermo‐Responsive Hydrogel Actuators with High Mechanical Properties and Rapid Response

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