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Publications

2022
1. S. Liese, A. Schlaich, and R. R. Netz, “Dielectric Constant of Aqueous Solutions of Proteins and Organic Polymers from Molecular Dynamics Simulations,” The Journal of Chemical Physics, 2022, doi: 10.1063/5.0089397.
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  @article{doi:10.1063/5.0089397, abstract = { The dielectric constant of water/oligomer mixtures, spanning the range from pure water to pure oligomeric melts, is investigated using molecular dynamics (MD) simulations. As prototypical water-soluble organic substances we consider neutral poly-glycine, poly-ethylene glycol and charged monomeric propanic acid. As the water content is reduced, the dielectric constant decreases but does not follow an ideal mixing behavior. The deviations from ideal mixing originate primarily in the non-linear relation between the oligomer mass fraction and collective polarization effects. We find that the dielectric constant is dominated by water polarization, even if the oligomer mass fraction exceeds 50\%. By a double extrapolation of the MD simulation results to the limit of vanishing water fraction and to the limit of infinite oligomeric chain length, we estimate the orientational contribution to the dielectric constant of the pure polymeric melts. By this procedure, we obtain ε = 17 {plus minus} 2 for polyglycine and ε = 1 {plus minus} 0.3 for polyethylene glycol. The large difference is rationalized by polarization correlations of glycine units. Interestingly, we find constant temperature simulations to outperform replica exchange simulations in terms of equilibration speed. }, author = {Liese, Susanne and Schlaich, Alexander and Netz, Roland R.}, doi = {10.1063/5.0089397}, eprint = {https://doi.org/10.1063/5.0089397}, journal = {The Journal of Chemical Physics}, title = {Dielectric Constant of Aqueous Solutions of Proteins and Organic Polymers from Molecular Dynamics Simulations}, url = {https://doi.org/10.1063/5.0089397 }, year = 2022 }
  Link
  https://doi.org/10.1063/5.0089397
2. S. Gravelle, C. Holm, and A. Schlaich, “Transport of thin water films: from thermally activated random walks to hydrodynamics,” The Journal of Chemical Physics, 2022, doi: 10.1063/5.0099646.
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  @article{doi:10.1063/5.0099646, abstract = { Under ambient atmospheric conditions, a thin film of water wets many solid surfaces, including insulators, ice, and salt. The film thickness as well as its transport behavior sensitively depend on the surrounding humidity. Understanding this intricate interplay is of highest relevance for water transport through porous media, particularly in the context of soil salinization induced by evaporation. Here, we use molecular simulations to evaluate the transport properties of thin water films on prototypical salt and soil interfaces, namely NaCl and silica solid surfaces. Our results showtwo distinct regimes for water transport: at low water coverage, the film permeance scales linearly with the adsorbed amount, in agreement with the activated random walk model.For thicker water films, the permeance scales as the adsorbed amount to the power of 3, in line with the Stokes equation. By comparing results obtained for silica and NaCl surfaces, we find that, at low water coverage, water permeance at the silica surface is considerably lower than at the NaCl surface, which we attribute to difference in hydrogen bonding. We also investigate the effect of atomic surface defects on the transport properties. Finally, in the context of water transport through porous material, we determine the humidity-dependent crossover between a vapor dominated and a thin film dominated transport regimes depending on the pore size. }, author = {Gravelle, Simon and Holm, Christian and Schlaich, Alexander}, doi = {10.1063/5.0099646}, eprint = {https://doi.org/10.1063/5.0099646}, journal = {The Journal of Chemical Physics}, title = {Transport of thin water films: from thermally activated random walks to hydrodynamics}, url = {https://doi.org/10.1063/5.0099646}, year = 2022 }
  Link
  https://doi.org/10.1063/5.0099646
2021
1. A. Schlaich, D. Jin, L. Bocquet, and B. Coasne, “Electronic screening using a virtual Thomas--Fermi fluid for predicting wetting and phase transitions of ionic liquids at metal surfaces,” Nature Materials, Nov. 2021, doi: 10.1038/s41563-021-01121-0.
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  @article{Schlaich2021, abstract = {Of relevance to energy storage, electrochemistry and catalysis, ionic and dipolar liquids display unexpected behaviours---especially in confinement. Beyond adsorption, over-screening and crowding effects, experiments have highlighted novel phenomena, such as unconventional screening and the impact of the electronic nature---metallic versus insulating---of the confining surface. Such behaviours, which challenge existing frameworks, highlight the need for tools to fully embrace the properties of confined liquids. Here we introduce a novel approach that involves electronic screening while capturing molecular aspects of interfacial fluids. Although available strategies consider perfect metal or insulator surfaces, we build on the Thomas--Fermi formalism to develop an effective approach that deals with any imperfect metal between these asymptotes. Our approach describes electrostatic interactions within the metal through a `virtual' Thomas--Fermi fluid of charged particles, whose Debye length sets the screening length $\lambda$. We show that this method captures the electrostatic interaction decay and electrochemical behaviour on varying $\lambda$. By applying this strategy to an ionic liquid, we unveil a wetting transition on switching from insulating to metallic conditions.}, author = {Schlaich, Alexander and Jin, Dongliang and Bocquet, Lyderic and Coasne, Benoit}, day = 11, doi = {10.1038/s41563-021-01121-0}, issn = {1476-4660}, journal = {Nature Materials}, month = {11}, title = {Electronic screening using a virtual Thomas--Fermi fluid for predicting wetting and phase transitions of ionic liquids at metal surfaces}, url = {https://doi.org/10.1038/s41563-021-01121-0}, year = 2021 }
  Link
  https://doi.org/10.1038/s41563-021-01121-0
2. G. Gonella et al., “Water at charged interfaces,” Nature Reviews Chemistry, vol. 5, no. 7, Art. no. 7, Jul. 2021, doi: 10.1038/s41570-021-00293-2.
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  @article{Gonella2021, abstract = {The ubiquity of aqueous solutions in contact with charged surfaces and the realization that the molecular-level details of water--surface interactions often determine interfacial functions and properties relevant in many natural processes have led to intensive research. Even so, many open questions remain regarding the molecular picture of the interfacial organization and preferential alignment of water molecules, as well as the structure of water molecules and ion distributions at different charged interfaces. While water, solutes and charge are present in each of these systems, the substrate can range from living tissues to metals. This diversity in substrates has led to different communities considering each of these types of aqueous interface. In this Review, by considering water in contact with metals, oxides and biomembranes, we show the essential similarity of these disparate systems. While in each case the classical mean-field theories can explain many macroscopic and mesoscopic observations, it soon becomes apparent that such theories fail to explain phenomena for which molecular properties are relevant, such as interfacial chemical conversion. We highlight the current knowledge and limitations in our understanding and end with a view towards future opportunities in the field.}, author = {Gonella, Grazia and Backus, Ellen H. G. and Nagata, Yuki and Bonthuis, Douwe J. and Loche, Philip and Schlaich, Alexander and Netz, Roland R. and K{\"u}hnle, Angelika and McCrum, Ian T. and Koper, Marc T. M. and Wolf, Martin and Winter, Bernd and Meijer, Gerard and Campen, R. Kramer and Bonn, Mischa}, day = 01, doi = {10.1038/s41570-021-00293-2}, issn = {2397-3358}, journal = {Nature Reviews Chemistry}, month = {7}, number = 7, pages = {466--485}, title = {Water at charged interfaces}, url = {https://doi.org/10.1038/s41570-021-00293-2}, volume = 5, year = 2021 }
  Link
  https://doi.org/10.1038/s41570-021-00293-2
3. I. Tischler, A. Schlaich, and C. Holm, “The Presence of a Wall Enhances the Probability for Ring-Closing Metathesis: Insights from Classical Polymer Theory and Atomistic Simulations,” Macromolecular Theory and Simulations, vol. 30, no. 2, Art. no. 2, 2021, doi: 10.1002/mats.202000076.
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  @article{tischler21a, abstract = {The probability distribution of chain ends meeting when one end of the polymer is fixed to a certain distance to a reflecting wall is investigated. For an ideal polymer chain the probability distribution can be evaluated analytically via classic polymer theory. These analytical predictions are compared to atomistic MD simulations of one tethered alkane chain close to the wall. The results demonstrate that a confining wall can lead to a significant increase in the return probability for the chain ends, and thus, can increase the occurrence of ring-closing reactions. It is further demonstrated that the excess return probability shows a maximum at a certain distance, thereby yielding an optimal catalyst position in the ring-closing reaction.}, annotation = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/mats.202000076}, author = {Tischler, Ingo and Schlaich, Alexander and Holm, Christian}, doi = {10.1002/mats.202000076}, issn = {1521-3919}, journal = {Macromolecular Theory and Simulations}, journaltitle = {Macromolecular Theory and Simulations}, langid = {english}, number = 2, pages = 2000076, shorttitle = {The {{Presence}} of a {{Wall Enhances}} the {{Probability}} for {{Ring-Closing Metathesis}}}, title = {The {{Presence}} of a {{Wall Enhances}} the {{Probability}} for {{Ring-Closing Metathesis}}: {{Insights}} from {{Classical Polymer Theory}} and {{Atomistic Simulations}}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mats.202000076}, urldate = {2022-05-30}, volume = 30, year = 2021 }
  Link
  https://onlinelibrary.wiley.com/doi/abs/10.1002/mats.202000076
2020
1. P. Loche, C. Ayaz, A. Wolde-Kidan, A. Schlaich, and R. R. Netz, “Universal and Nonuniversal Aspects of Electrostatics in Aqueous Nanoconfinement,” The Journal of Physical Chemistry B, vol. 124, no. 21, Art. no. 21, 2020, doi: 10.1021/acs.jpcb.0c01967.
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  @article{doi:10.1021/acs.jpcb.0c01967, abstract = { Dielectric water properties, which significantly change in confinement, determine electrostatic interactions and thereby influence all molecular forces and chemical reactions. We present comparative simulations of water between graphene sheets, decanol monolayers, and phospholipid and glycolipid bilayers. Generally, dielectric profiles strongly differ in perpendicular and parallel surface directions and for large surface separation decay to the bulk value 1–2 nm away from the surface. Polar surface groups enhance the local interfacial dielectric response and for phospholipid bilayers induce a giant parallel contribution. A mapping on a box model with asymptotically determined effective water layer widths demonstrates that the perpendicular effective dielectric constant for all systems decreases for confinement below a nanometer, while the parallel one stays rather constant. The confinement-dependent perpendicular effective dielectric constant for graphene is in agreement with experimental data only if the effective water layer width is suitably adjusted. The interactions between two charges at small separation depend on the product of parallel and perpendicular effective water dielectric components; for large separation the interactions depend on the confining medium. For metallic confining media the interactions at large separation decay exponentially with a decay length that depends on the ratio of the effective parallel and perpendicular water dielectric components. }, author = {Loche, Philip and Ayaz, Cihan and Wolde-Kidan, Amanuel and Schlaich, Alexander and Netz, Roland R.}, doi = {10.1021/acs.jpcb.0c01967}, eprint = {https://doi.org/10.1021/acs.jpcb.0c01967}, journal = {The Journal of Physical Chemistry B}, note = {PMID: 32364728}, number = 21, pages = {4365-4371}, title = {Universal and Nonuniversal Aspects of Electrostatics in Aqueous Nanoconfinement}, url = {https://doi.org/10.1021/acs.jpcb.0c01967 }, volume = 124, year = 2020 }
  Link
  https://doi.org/10.1021/acs.jpcb.0c01967
2. J. C. F. Schulz, A. Schlaich, M. Heyden, R. R. Netz, and J. Kappler, “Molecular interpretation of the non-Newtonian viscoelastic behavior of liquid water at high frequencies,” Phys. Rev. Fluids, vol. 5, no. 10, Art. no. 10, Oct. 2020, doi: 10.1103/PhysRevFluids.5.103301.
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  @article{PhysRevFluids.5.103301, abstract = {Using classical and $a\phantom{\rule{0}{0ex}}b$ $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o$ molecular dynamics simulations, we calculate the frequency-dependent shear viscosity of pure liquid water and water--glycerol mixtures. In agreement with recent experiments, we find deviations from Newtonian-fluid behavior in the THz regime, and introduce a continuum viscoelastic model (CVM) to describe the observed viscosity spectrum of pure water. We relate features of the CVM to the microscopic dynamics of water molecule clusters. Our model bridges hydrodynamic and molecular approaches to water dynamics, quantifying the viscoelastic response on short timescales where a Newtonian-fluid model breaks down.}, author = {Schulz, Julius C. F. and Schlaich, Alexander and Heyden, Matthias and Netz, Roland R. and Kappler, Julian}, doi = {10.1103/PhysRevFluids.5.103301}, journal = {Phys. Rev. Fluids}, month = {10}, number = 10, numpages = {17}, pages = 103301, publisher = {American Physical Society}, title = {Molecular interpretation of the non-Newtonian viscoelastic behavior of liquid water at high frequencies}, url = {https://link.aps.org/doi/10.1103/PhysRevFluids.5.103301}, volume = 5, year = 2020 }
  Link
  https://link.aps.org/doi/10.1103/PhysRevFluids.5.103301

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