Morphology and Hydrophobicity of Humic Coatings on Glass as Studied by Atomic Force Microscopy (AFM) and Contact Angle Measurements
In nature, many functional nanoarchitectures are self-assembled due to supramolecular interactions of natural organic matter and surfaces of mineral particles. However, direct evidence for molecular mechanisms responsible for these interactions is still missing. Here, we developed silanol derivatives of humic substances capable of self-assembling onto hydroxylated surfaces. By using humic substances from peat and coal and DNA array glass slides, we show that humic adlayers were homogeneous on macroscale, but separated into domains of nanosize in coal HS and submicro size in peat HS. The peat adlayers were characterized with larger roughness of 11 nm versus 5 nm for coal. Measurement of the contact angle showed that application of humic coatings leads to an increase in hydrophobicity of glass. It was shown that treatment of soil aggregates with silanol derivatives of humic acids increases water stability of the aggregates.
KeywordsHumic Coating Water-solid interface Hydrophobicity Morphology AFM
This work was supported by the grants of the Russian Foundation for Basic Research (11-03-12177 and 10-03-00803) and by the state contract GK 16.740.11.0183 of the Russian Ministry for Education and Science.
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