Molecular Origins of the Zeta Potential
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60076658%3A12310%2F16%3A43890669" target="_blank" >RIV/60076658:12310/16:43890669 - isvavai.cz</a>
Result on the web
<a href="http://pubs.acs.org/doi/abs/10.1021/acs.langmuir.6b02493" target="_blank" >http://pubs.acs.org/doi/abs/10.1021/acs.langmuir.6b02493</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acs.langmuir.6b02493" target="_blank" >10.1021/acs.langmuir.6b02493</a>
Alternative languages
Result language
angličtina
Original language name
Molecular Origins of the Zeta Potential
Original language description
The zeta potential (ZP) is an oft-reported measure of the macroscopic charge state of solid surfaces and colloidal particles in contact with solvents. However, the origin of this readily measurable parameter has remained divorced from the molecular-level processes governing the underlying electrokinetic phenomena, which limits its usefulness. Here, we connect the macroscopic measure to the microscopic realm through nonequilibrium molecular dynamics simulations of electroosmotic flow between parallel slabs of the hydroxylated (110) rutile (TiO2) surface. These simulations provided streaming mobilities, which were converted to ZP via the commonly used Helmholtz-Smoluchowski equation. A range of rutile surface charge densities (0.1 to -0.4 C/m(2)), corresponding to pH values between about 2.8 and 9.4, in RbCl, NaCl, and SrCl2 aqueous solutions, were modeled and compared to experimental ZPs for TiO2 particle suspensions. Simulated ZPs qualitatively agree with experiment and show that anomalous ZP values and inequalities between the point of zero charge derived from electrokinetic versus pH titration measurements both arise from differing co- and counterion sorption affinities. We show that at the molecular level the ZP arises from the delicate interplay of spatially varying dynamics, structure, and electrostatics in a narrow interfacial region within about 15 angstrom of the surface, even in dilute salt solutions. This contrasts fundamentally with continuum descriptions of such interfaces, which predict the ZP response region to be inversely related to ionic strength. In reality the properties of this interfacial region are dominated by relatively immobile and structured water. Consequently, viscosity values are substantially greater than in the bulk, and electrostatic potential profiles are oscillatory in nature.
Czech name
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Czech description
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Classification
Type
J<sub>x</sub> - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP classification
CF - Physical chemistry and theoretical chemistry
OECD FORD branch
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Result continuities
Project
<a href="/en/project/GA13-08651S" target="_blank" >GA13-08651S: Computational study of interactions of organic matter and biomolecules with mineral surfaces</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2016
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Langmuir
ISSN
0743-7463
e-ISSN
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Volume of the periodical
32
Issue of the periodical within the volume
40
Country of publishing house
US - UNITED STATES
Number of pages
10
Pages from-to
10189-10198
UT code for WoS article
000385336000006
EID of the result in the Scopus database
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