Molecular Simulations of Hydrogels

Košovan, Peter; Richter, Tobias; Holm, Christian

doi:10.1007/978-3-319-01683-2_16

Cited by 24 publications

(25 citation statements)

References 116 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In figure 3 the scaled equilibrium extension R eq /R max is shown as a function of the salt concentration in the reservoir (c res salt ) and the charge fraction ( f ). In agreement with literature [19,21,15,60,23,24,26,27,61,62,28,29] we find that the gel swells a) more with increased charge fraction f and b) less with higher salt concentration in the reservoir.…”

Section: Swelling Equilibriasupporting

confidence: 92%

“…Macroscopic polyelectrolyte gels with monodisperse chain lengths have been simulated using molecular dynamics (MD) simulations with periodic boundary conditions (PBCs) (cf. periodic gel model) [19,20,21,22,23,24,25,26,27,28,29,30]. These coarse-grained simulations provide predictions about mechanical and swelling properties of macroscopic gels and revealed microscopic insights about validities of various analytical predictions.…”

Section: Polyelectrolyte Gelsmentioning

confidence: 94%

See 1 more Smart Citation

Cell Model Approaches for Predicting the Swelling and Mechanical Properties of Polyelectrolyte Gels

Landsgesell

Holm

2019

Macromolecules

Self Cite

View full text Add to dashboard Cite

We present two successive mean-field approximations for describing the mechanical properties and the swelling equilibrium of polyelectrolyte gels in contact with a salt solution. The first mean-field approximation reduces the many-chain problem of a gel to a corresponding single chain problem. The second mean-field step integrates out the degrees of freedom of the flexible chain and the ions. It replaces the particle-based description of the polyelectrolyte with suitable charge distributions and an effective elasticity term. These simplifications result in a computationally very efficient Poisson-Boltzmann cell-gel description. Despite their simplicity, the single chain cell-gel model shows excellent and the PB model very good agreement with explicit molecular dynamics simulations of the reference periodic monodisperse network model for varying chain length, polymer charge fraction, and external reservoir salt concentrations. Comparisons of our models to the Katchalsky model reveal that our approach is superior for strongly charged chains and can also predict the bulk moduli more accurately. We further discuss chain length polydispersity effects, investigate changes in the solvent permittivity, and demonstrate the robustness of our approach to parameter variations coming from several modeling assumptions.

show abstract

Section: Swelling Equilibriasupporting

confidence: 92%

Section: Polyelectrolyte Gelsmentioning

confidence: 94%

Cell Model Approaches for Predicting the Swelling and Mechanical Properties of Polyelectrolyte Gels

Landsgesell

Holm

2019

Macromolecules

Self Cite

View full text Add to dashboard Cite

show abstract

“…Tailoring polyelectrolyte gels to their applications requires a sufficiently accurate prediction of their swelling capabilities and elastic responses, a task that still goes beyond analytical approaches [10,11,12,13,14,15,16,17,18]. So far only all-atom simulations of short single chains in the bulk (not of whole hydrogels) with explicit water have been performed [19,20,21,22]. On the other hand, coarse-grained polyelectrolyte network models have demonstrated their ability to amend analytical approaches, showing that structural microscopic details can have noticeable effects on the macroscopic properties such as the swelling [23,24,25,26,27,28,29,30,31,32].…”

mentioning

confidence: 99%

Modeling Gel Swelling Equilibrium in the Mean Field: From Explicit to Poisson-Boltzmann Models

et al. 2019

Self Cite

View full text Add to dashboard Cite

We develop a double mean-field theory for charged macrogels immersed in electrolyte solutions in the spirit of the cell model approach.We first demonstrate that the equilibrium sampling of a single explicit coarse-grained charged polymer in a cell yields accurate predictions of the swelling equilibrium if the geometry is suitably chosen and all pressure contributions have been incorporated accurately. We then replace the explicit flexible chain by a suitably modeled penetrable charged rod that allows to compute all pressure terms within the Poisson-Boltzmann approximation. This model, albeit computationally cheap, yields excellent predictions of swelling equilibria under varying chain length, polymer charge fraction, and external reservoir salt concentrations when compared to coarse-grained molecular dynamics simulations of charged macrogels. We present an extension of the model to the experimentally relevant cases of pH-sensitive gels. arXiv:1905.04960v1 [cond-mat.soft]Polyelectrolyte gels consist of crosslinked charged polymers (polyelectrolytes) that can be synthesized with various topologies and are produced in sizes ranging from nanometers (nanogels) up to centimeters (macrogels) [1,2]. They show a large, reversible uptake of water that is exploited in numerous dailylife products, such as in superabsorbers, cosmetics, pharmaceuticals [3,4,5], agriculture [6,7], or quite recently water desalination [8,9]. Tailoring polyelectrolyte gels to their applications requires a sufficiently accurate prediction of their swelling capabilities and elastic responses, a task that still goes beyond analytical approaches [10,11,12,13,14,15,16,17,18]. So far only all-atom simulations of short single chains in the bulk (not of whole hydrogels) with explicit water have been performed [19,20,21,22]. On the other hand, coarse-grained polyelectrolyte network models have demonstrated their ability to amend analytical approaches, showing that structural microscopic details can have noticeable effects on the macroscopic properties such as the swelling [23,24,25,26,27,28,29,30,31,32]. Macroscopic gels with monodisperse chain length can be simulated with microscopic detail using molecular dynamics (MD) simulations with periodic boundary conditions (PBCs) (cf. periodic gel model ) where a unit gel section is connected periodically to yield an infinite gel without boundaries. However, even MD simulations of periodic gels remain computationally very expensive due to the many particles and the slow relaxation times of the involved polymers. Thus, the development of computationally efficient mean-field models capable of predicting swelling equilibria have been of scientific interest in the last years [33,15,31,32]. First ideas of using a Poisson-Boltzmann (PB) cell model under tension were put forward by Mann for salt-free gels, with moderate success [33].About sixty years ago Katchalsky and Michaeli [11] suggested a free energy model that has recently been shown to predict swelling equilibria reasonably well [31] when compared to MD simulat...

show abstract

“…Poly( N ‐isopropylacrylamide) (PNIPAAm) and its derivatives are some of the most studied thermoresponsive polymers . The studies involving PNIPAAm properties cover a wide range of areas of knowledge, which extend for instance from the theoretical and computational field to physical–chemical properties in solution . Aqueous solutions of PNIPAAm present a sharp LCST at 32 °C, which is not dependent on the polymer molar mass or molar mass dispersity .…”

Section: Introductionmentioning

confidence: 99%

Thermoresponsive hydrogels based on sucrose 1‐O′‐methacrylate and N‐isopropylacrylamide: Synthesis, properties, and applications

Menezes

Camilo

Felisberti

2017

J of Applied Polymer Sci

View full text Add to dashboard Cite

Chemically crosslinked hydrogels composed of carbohydrate‐based and thermoresponsive monomers, sucrose 1‐O′‐methacrylate (SMA), sucrose dimethacrylate, and N‐isopropylacrylamide, respectively, were synthesized by free radical polymerization. These materials were characterized with respect to their composition, thermoresponsiveness, porosity, degradability, and as drug and protein delivery systems. Swelling studies, thermomechanical analysis, and differential scanning calorimetry showed that the lower critical solution temperature behavior of the hydrogels can be controlled by the SMA amount in the copolymers. On the other hand, thermoporometry showed that the pore size is somewhat dependent on the composition, which is confirmed by scanning electron microscopy. Hydrolytic degradation studies indicated that SMA side chains, as well as the crosslinker (sucrose dimethacrylate), are hydrolysable at corporeal temperature and pH 10, and the water swelling capability of the resulting materials increases as the hydrolysis degree increases. Finally, protein delivery studies revealed that the kinetics of release can be tailored by the copolymer composition. The results of this study suggest the potential application of these hydrogels in drug delivery systems and tissue engineering. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45495.

show abstract

Molecular Simulations of Hydrogels

Cited by 24 publications

References 116 publications

Cell Model Approaches for Predicting the Swelling and Mechanical Properties of Polyelectrolyte Gels

Cell Model Approaches for Predicting the Swelling and Mechanical Properties of Polyelectrolyte Gels

Modeling Gel Swelling Equilibrium in the Mean Field: From Explicit to Poisson-Boltzmann Models

Thermoresponsive hydrogels based on sucrose 1‐O′‐methacrylate and N‐isopropylacrylamide: Synthesis, properties, and applications

Contact Info

Product

Resources

About