How water wets and self-hydrophilizes nanopatterns of physisorbed hydrocarbons

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:606

Article

Diaz, Diego^1,8  Nickel, Ole²  Moraga, Nicolas¹  Catalan, Rodrigo E.¹  Retamal, Maria Jose¹  Zelada, Hugo¹  Cisternas, Marcelo¹  Meissner, Robert^2,9  Huber, Patrick^3,4,5  Corrales, Tomas P.⁶  Volkmann, Ulrich G.^1,7 

[1] Pontificia Univ Catolica Chile, Inst Fis, Santiago 7820436, Chile

[2] Hamburg Univ Technol, Inst Polymers & Composites, D-21073 Hamburg, Germany

[3] Hamburg Univ Technol, Inst Mat & Xray Phys, D-21073 Hamburg, Germany

[4] DESY, Ctr Xray & Nano Sci CXNS, D-22603 Hamburg, Germany

[5] Univ Hamburg, Ctr Hybrid Nanostruct CHyN, D-22607 Hamburg, Germany

[6] Univ Tecn Federico Santa Maria, Dept Fis, Valparaiso 2390123, Chile

[7] Pontificia Univ Catolica Chile, Ctr Invest Nanotecnol & Mat Avanzados CIEN UC, Santiago 7820436, Chile

[8] Max Planck Inst Polymer Res, Ackermannweg 10, D-55128 Mainz, Germany

[9] Helmholtz Zentrum Hereon, Inst Surface Sci, D-21494 Geesthacht, Germany

关键词: Wetting;    n-Alkane;    Silica;    Silicon;    Atomic force microscopy;    Electron microscopy;    Molecular dynamics simulation;   

DOI  :  10.1016/j.jcis.2021.07.121

来源: Elsevier

【 摘 要 】

Hypothesis: Weakly bound, physisorbed hydrocarbons could in principle provide a similar waterrepellency as obtained by chemisorption of strongly bound hydrophobic molecules at surfaces. Experiments: Here we present experiments and computer simulations on the wetting behaviour of water on molecularly thin, self-assembled alkane carpets of dotriacontane (n-C32H66 or C32) physisorbed on the hydrophilic native oxide layer of silicon surfaces during dip-coating from a binary alkane solution. By changing the dip-coating velocity we control the initial C32 surface coverage and achieve distinct film morphologies, encompassing homogeneous coatings with self-organised nanopatterns that range from dendritic nano-islands to stripes. Findings: These patterns exhibit a good water wettability even though the carpets are initially prepared with a high coverage of hydrophobic alkane molecules. Using in-liquid atomic force microscopy, along with molecular dynamics simulations, we trace this to a rearrangement of the alkane layers upon contact with water. This restructuring is correlated to the morphology of the C32 coatings, i.e. their fractal dimen-sion. Water molecules displace to a large extent the first adsorbed alkane monolayer and thereby reduce the hydrophobic C32 surface coverage. Thus, our experiments evidence that water molecules can very effectively hydrophilize initially hydrophobic surfaces that consist of weakly bound hydrocarbon carpets. (c) 2021 Elsevier Inc. All rights reserved.

【 授权许可】

Free