Theoretical predictions of structures in dispersions containing charged colloidal particles and nonadsorbing polymers
(2016) In Physical Chemistry Chemical Physics 18(16). p.1142211434 Abstract
We develop a theoretical model to describe structural effects on a specific system of charged colloidal polystyrene particles, upon the addition of nonadsorbing PEG polymers. This system has previously been investigated experimentally, by scattering methods, so we are able to quantitatively compare predicted structure factors with corresponding experimental data. Our aim is to construct a model that is coarsegrained enough to be computationally manageable, yet detailed enough to capture the important physics. To this end, we utilize classical polymer density functional theory, wherein all possible polymer configurations are accounted for, subject to a meanfield Boltzmann weight. We make efforts to counteract drawbacks with this... (More)
We develop a theoretical model to describe structural effects on a specific system of charged colloidal polystyrene particles, upon the addition of nonadsorbing PEG polymers. This system has previously been investigated experimentally, by scattering methods, so we are able to quantitatively compare predicted structure factors with corresponding experimental data. Our aim is to construct a model that is coarsegrained enough to be computationally manageable, yet detailed enough to capture the important physics. To this end, we utilize classical polymer density functional theory, wherein all possible polymer configurations are accounted for, subject to a meanfield Boltzmann weight. We make efforts to counteract drawbacks with this meanfield approach, resulting in structural predictions that agree very well with computationally more demanding simulations. Electrostatic interactions are handled at the fully nonlinear PoissonBoltzmann level, and we demonstrate that a linearization leads to less accurate predictions. The particle charge is an experimentally unknown parameter. We define the surface charge such that the experimental and theoretical gel point at equal polymer concentration coincide. Assuming a fixed surface charge for a certain salt concentration, we find very good agreements between measured and predicted structure factors across a wide range of polymer concentrations. We also present predictions for other structural quantities, such as radial distribution functions, and cluster size distributions. Finally, we demonstrate that our model predicts the occurrence of equilibrium clusters at high polymer concentrations, but low particle volume fractions and salt levels.
(Less)
 author
 Xie, Fei ^{LU} ; Turesson, Martin ^{LU} ; Woodward, Clifford E.; Van Gruijthuijsen, Kitty; Stradner, Anna ^{LU} and Forsman, Jan ^{LU}
 organization
 publishing date
 20160428
 type
 Contribution to journal
 publication status
 published
 subject
 in
 Physical Chemistry Chemical Physics
 volume
 18
 issue
 16
 pages
 13 pages
 publisher
 Royal Society of Chemistry
 external identifiers

 Scopus:84967139742
 ISSN
 14639076
 DOI
 10.1039/c5cp07814h
 language
 English
 LU publication?
 yes
 id
 02a6ac4092f24ea28203359acbff073a
 date added to LUP
 20160930 07:53:07
 date last changed
 20161017 10:07:37
@misc{02a6ac4092f24ea28203359acbff073a, abstract = {<p>We develop a theoretical model to describe structural effects on a specific system of charged colloidal polystyrene particles, upon the addition of nonadsorbing PEG polymers. This system has previously been investigated experimentally, by scattering methods, so we are able to quantitatively compare predicted structure factors with corresponding experimental data. Our aim is to construct a model that is coarsegrained enough to be computationally manageable, yet detailed enough to capture the important physics. To this end, we utilize classical polymer density functional theory, wherein all possible polymer configurations are accounted for, subject to a meanfield Boltzmann weight. We make efforts to counteract drawbacks with this meanfield approach, resulting in structural predictions that agree very well with computationally more demanding simulations. Electrostatic interactions are handled at the fully nonlinear PoissonBoltzmann level, and we demonstrate that a linearization leads to less accurate predictions. The particle charge is an experimentally unknown parameter. We define the surface charge such that the experimental and theoretical gel point at equal polymer concentration coincide. Assuming a fixed surface charge for a certain salt concentration, we find very good agreements between measured and predicted structure factors across a wide range of polymer concentrations. We also present predictions for other structural quantities, such as radial distribution functions, and cluster size distributions. Finally, we demonstrate that our model predicts the occurrence of equilibrium clusters at high polymer concentrations, but low particle volume fractions and salt levels.</p>}, author = {Xie, Fei and Turesson, Martin and Woodward, Clifford E. and Van Gruijthuijsen, Kitty and Stradner, Anna and Forsman, Jan}, issn = {14639076}, language = {eng}, month = {04}, number = {16}, pages = {1142211434}, publisher = {ARRAY(0x687daa8)}, series = {Physical Chemistry Chemical Physics}, title = {Theoretical predictions of structures in dispersions containing charged colloidal particles and nonadsorbing polymers}, url = {http://dx.doi.org/10.1039/c5cp07814h}, volume = {18}, year = {2016}, }