Determination and evaluation of the nonadditivity in wetting of molecularly heterogeneous surfaces.

Autor: Luo Z; Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland., Murello A; Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland., Wilkins DM; Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland., Kovacik F; Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland., Kohlbrecher J; Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen, Switzerland., Radulescu A; Forschungszentrum Jülich Gmbh, Jülich Center for Neutron Science at Heinz Maier-Leibnitz Zentrum, 85747 Garching, Germany., Okur HI; Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland., Ong QK; Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland., Roke S; Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.; Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland., Ceriotti M; Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland., Stellacci F; Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; francesco.stellacci@epfl.ch.; Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
Jazyk: angličtina
Zdroj: Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2019 Dec 17; Vol. 116 (51), pp. 25516-25523. Date of Electronic Publication: 2019 Dec 02.
DOI: 10.1073/pnas.1916180116
Abstrakt: The interface between water and folded proteins is very complex. Proteins have "patchy" solvent-accessible areas composed of domains of varying hydrophobicity. The textbook understanding is that these domains contribute additively to interfacial properties (Cassie's equation, CE). An ever-growing number of modeling papers question the validity of CE at molecular length scales, but there is no conclusive experiment to support this and no proposed new theoretical framework. Here, we study the wetting of model compounds with patchy surfaces differing solely in patchiness but not in composition. Were CE to be correct, these materials would have had the same solid-liquid work of adhesion ( W SL ) and time-averaged structure of interfacial water. We find considerable differences in W SL , and sum-frequency generation measurements of the interfacial water structure show distinctively different spectral features. Molecular-dynamics simulations of water on patchy surfaces capture the observed behaviors and point toward significant nonadditivity in water density and average orientation. They show that a description of the molecular arrangement on the surface is needed to predict its wetting properties. We propose a predictive model that considers, for every molecule, the contributions of its first-nearest neighbors as a descriptor to determine the wetting properties of the surface. The model is validated by measurements of W SL in multiple solvents, where large differences are observed for solvents whose effective diameter is smaller than ∼6 Å. The experiments and theoretical model proposed here provide a starting point to develop a comprehensive understanding of complex biological interfaces as well as for the engineering of synthetic ones.
Competing Interests: The authors declare no competing interest.
(Copyright © 2019 the Author(s). Published by PNAS.)
Databáze: MEDLINE
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