Multiphysics Modelling of Volume Phase Transition of Ionic Hydrogels Responsive to Thermal Stimulus

Li, Hua; Wang, Xiaogui; Wang, Zijie; Lam, K.Y.

doi:10.1002/mabi.200500082

Cited by 18 publications

(17 citation statements)

References 33 publications

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“…In recent years, many studies have been done on environment sensitive hydrogels that undergo substantial controllable volume changes in response to small variations in solution conditions such as pH, electric field, and temperature. [1][2][3][4][5][6][7][8][9][10] With the volume transition characteristic, micro-scale environment-sensitive hydrogels have gained widespread acceptance for smart biomaterial applications in areas of sensors, actuators, microfluidic controllers, drug delivery systems, and biomedical and bio-microelectromechanical system (BioMEMS) devices. [11,12] For the broad range of BioMEMS applications, the environmental sensitive hydrogels are required to have biocompatibility, low power consumption, fast environmental response and high mechanical strength.…”

Section: Introductionmentioning

confidence: 99%

Multiphysics Modeling of Electrochemomechanically Smart Microgels Responsive to Coupled pH/Electric Stimuli

Luo

Lam

2009

Macromolecular Bioscience

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A multiphysics model is developed to simulate the responsive behavior of smart pH-/electric-sensitive hydrogels when immersed into pH buffer solution and subjected to an externally applied electric field, which is termed the MECpHe model. Comparison with experimental data shows the MECpHe model to be accurate and stable. The influence of the externally applied electric voltage is discussed with respect to the distribution of diffusive ionic species and the displacement of the hydrogel strip. The influences of initial charge density and ionic strength on the swelling ratio and the bending deformation of the microgel strip are studied.

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Section: Introductionmentioning

confidence: 99%

Multiphysics Modeling of Electrochemomechanically Smart Microgels Responsive to Coupled pH/Electric Stimuli

Luo

Lam

2009

Macromolecular Bioscience

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“…However, the search of open literature shows that most of the published studies have so far been experiment‐based 11, 12. Several theoretical studies were made for modeling of the hydrogel‐based drug delivery system13, 14 and optimization of the hydrogel membrane,15 and for simulations of the smart hydrogels responding to the environmental stimuli including the solution pH16–19 and temperature 20–22. In terms of the stimulus of externally applied electrical field, few efforts were put into the simulation of the electric‐sensitive hydrogels and hydrogel‐like membranes.…”

Section: Introductionmentioning

confidence: 99%

“…11,12 Several theoretical studies were made for modeling of the hydrogel-based drug delivery system 13,14 and optimization of the hydrogel membrane, 15 and for simulations of the smart hydrogels responding to the environmental stimuli including the solution pH [16][17][18][19] and temperature. [20][21][22] In terms of the stimulus of externally applied electrical field, few efforts were put into the simulation of the electric-sensitive hydrogels and hydrogel-like membranes. Several published studies include the biphasic model, 23 the swelling thermo-analog theory, 24 the bicomponent theory, 25 the electromechanical theory, 26 the triphasic mechano-electro-chemical theory, 27 and the semiquantitative theory.…”

Section: Introductionmentioning

confidence: 99%

Modeling of electric‐stimulus‐responsive hydrogels immersed in different bathing solutions

Luo

Birgersson

et al. 2007

J Biomedical Materials Res

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By reformulation of the fixed charge density and consideration of finite deformation, a previous model simulating the pH-sensitive hydrogels is refined in this paper for extension to simulating the electric-sensitive hydrogels, which is termed the refined multi-effect-coupling electric-stimulus (rMECe) model. The rMECe model is based on the assumptions: (a) the hydrogel is isotropic and macroscopically homogeneous, (b) all the three phases are incompressible, including the polymeric solid matrix, interstitial water and mobile ions, (c) the effect of electro-osmosis is neglected, (d) bath solution is ideal so that the variation of the activity coefficients with ionic strength can be negligible, i.e., its effect on the concentration profiles is negligible, (e) the smart hydrogel is immersed in an unstirred solution in vibration-free experimental device; the bulk flow of fluid or hydrodynamic velocity can thus be eliminated and subsequently the convective flux is neglected, and (f) the pore of the present hydrogel is narrow enough so that the diffusion dominates the transmission of flux. The model consists of nonlinear coupled partial differential governing equations with the coupling effects of chemo-electro-mechanical multi-energy domains and the fixed charge density with the effect of externally applied electric-field. By comparing the simulating results with experimental data extracted from literature, a very good agreement is achieved and thus this validates the computing accuracy and stability of model. The present rMECe model shows the capability of efficiently predicting the ionic transport and the performance of the hydrogels when they are immersed in a bath solution subject to externally applied electric voltage. The model is used for quantitative analysis of the electric-sensitive hydrogels and for discussion of the influences of several physical parameters on the response of the hydrogels, including the externally applied electric voltage, the initially fixed charge density, and the ionic strength and valence of surrounding solution.

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“…The strip is fixated at one end electric field, leads to a bending of the non which can be used for sensors and actuators in biological and other aqueous environments reproduced and analyzed in detail in various numerical studies [ Equations (6)- (9) are typically solved with finite element methods. Alternatively, meshless methods have been used [39,40,50,[53][54][55][56], which are conceptually more complex but avoid the definition and adaptation of a mesh grid during the simulation. In finite element and meshless methods, boundary conditions have to be defined on the hydrogel surface with a flow velocity , is added to the right side of Equation obeys the Poisson equation:…”

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confidence: 99%

“…. induced swelling and deformation of hydrogels have been investigated dependent swelling is presented in [50]. ribution has been calculated as a function have studied the curling effect of articular cartilage with A system of particular interest, which is frequently investigated experimentally [51], consists of a hydrogel strip in water between two electrodes.…”

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Simulation of Stimuli-Responsive Polymer Networks

Gruhn

Emmerich

2013

Chemosensors

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The structure and material properties of polymer networks can depend sensitively on changes in the environment. There is a great deal of progress in the development of stimuli-responsive hydrogels for applications like sensors, self-repairing materials or actuators. Biocompatible, smart hydrogels can be used for applications, such as controlled drug delivery and release, or for artificial muscles. Numerical studies have been performed on different length scales and levels of details. Macroscopic theories that describe the network systems with the help of continuous fields are suited to study effects like the stimuli-induced deformation of hydrogels on large scales. In this article, we discuss various macroscopic approaches and describe, in more detail, our phase field model, which allows the calculation of the hydrogel dynamics with the help of a free energy that considers physical and chemical impacts. On a mesoscopic level, polymer systems can be modeled with the help of the self-consistent field theory, which includes the interactions, connectivity, and the entropy of the polymer chains, and does not depend on constitutive equations. We present our recent extension of the method that allows the study of the formation of nano domains in reversibly crosslinked block copolymer networks. Molecular simulations of polymer networks allow the investigation of the behavior of specific systems on a microscopic scale. As an example for microscopic modeling of stimuli sensitive polymer networks, we present our Monte Carlo simulations of a filament network system with crosslinkers

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Multiphysics Modelling of Volume Phase Transition of Ionic Hydrogels Responsive to Thermal Stimulus

Cited by 18 publications

References 33 publications

Multiphysics Modeling of Electrochemomechanically Smart Microgels Responsive to Coupled pH/Electric Stimuli

Multiphysics Modeling of Electrochemomechanically Smart Microgels Responsive to Coupled pH/Electric Stimuli

Modeling of electric‐stimulus‐responsive hydrogels immersed in different bathing solutions

Simulation of Stimuli-Responsive Polymer Networks

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