The pH-Dependent Swelling of Weak Polyelectrolyte Hydrogels Modeled at Different Levels of Resolution
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F22%3A10452100" target="_blank" >RIV/00216208:11310/22:10452100 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=QS2K5JfMX~" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=QS2K5JfMX~</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acs.macromol.1c02489" target="_blank" >10.1021/acs.macromol.1c02489</a>
Alternative languages
Result language
angličtina
Original language name
The pH-Dependent Swelling of Weak Polyelectrolyte Hydrogels Modeled at Different Levels of Resolution
Original language description
The swelling of polyelectrolyte hydrogels has beenoften explained using simple models derived from the Flory-Rehnermodel. While these models qualitatively predict the experimentallyobserved trends, they also introduce strong approximations andneglect some important contributions. Consequently, they some-times incorrectly ascribe the observed trends to contributions whichare of minor importance under the given conditions. In this work, weinvestigate the swelling properties of weak (pH-responsive)polyelectrolyte gels at various pH and salt concentrations, using ahierarchy of models, gradually introducing various approximations.For thefirst time, we introduce a three-dimensional particle-basedmodel which accounts for the topology of the hydrogel network, forelectrostatic interactions between gel segments and small ions, andfor acid-base equilibrium coupled to the Donnan partitioning of small ions. This model is the most accurate one; therefore, we useit as a reference when assessing the effect of various approximations. As thefirst approximation, we introduce the affine deformation,which allows us to replace the network of many chains by a single chain, while retaining the particle-based representation. In the nextstep, we use the mean-field approximation to replace particles by densityfields, combining the Poisson-Boltzmann equation withelastic stretching of the chain. Finally, we introduce an ideal gel model by neglecting the electrostatics while retaining all otherfeatures of the previous model. Comparing predictions from all four models allows us to understand which contributions dominate athigh or low pH or salt concentrations. We observe that thefield-based models overestimate the ionization degree of the gel becausethey underestimate the electrostatic interactions. Nevertheless, a cancellation of effects on the electrostatic interactions and Donnanpartitioning causes both particle-based andfield-based models to consistently predict the swelling of the gels as a function of pH andsalt concentration. Thus, we can conclude that any of the employed models can rationalize the known experimental trends in gelswelling, however, only the particle-based models fully account for the true effects causing these trends. The full understanding ofdifferences between various models is important when interpreting experimental results in the framework of existing theories and forascribing the observed trends to particular contributions, such as the Donnan partitioning of ions, osmotic pressure, or electrostaticinteractions.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10403 - Physical chemistry
Result continuities
Project
<a href="/en/project/GC21-31978J" target="_blank" >GC21-31978J: Simulations of reaction equilibria in polymer systems - method development and applications</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2022
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Macromolecules
ISSN
0024-9297
e-ISSN
1520-5835
Volume of the periodical
55
Issue of the periodical within the volume
8
Country of publishing house
US - UNITED STATES
Number of pages
13
Pages from-to
3176-3188
UT code for WoS article
000796258500018
EID of the result in the Scopus database
2-s2.0-85125793570