Superhydrophobicity Mechanism and Nanoscale Profiling of PDMS-Modified Kaolinite Nanolayers via Ab Initio-MD Simulation and Atomic Force Microscopy Study

Abstract

This study aimed to investigate the superhydrophobic mechanism of kaolinite particles modified with poly­(dimethylsiloxane) (PDMS), which has potential as a superior hydrophobic coating. The study employed a combination of density functional theory (DFT) simulation modeling, characterization of the chemical properties and microstructure, contact angle measurements, and chemical force spectroscopy of atomic force microscopy. The results showed successful PDMS grafting onto the kaolinite surface, resulting in micro- and nanoscale roughness and a contact angle of 165°, indicating a successful superhydrophobic effect. The study also identified the mechanism of the hydrophobic interaction through two-dimensional micro- and nanoscale hydrophobicity images, highlighting the potential of this approach for developing new hydrophobic coatings.

Molecular Dynamics Simulation of the Interaction within the Carboxymethyl Cellulose-Modified Montmorillonite Lamellae at Aggressive CuCl2 Concentrations

“…Molecular dynamics (MD) simulation has become a complementary method to experimental studies to investigate the microscopic mechanisms of clay–polymer interactions . In recent years, many MD researches of the clay–polymer composites have been conducted including the mostly used polymer types for the organo-modified engineering clay barriers, such as poly­(acrylic acid) (PAA), polyacrylamide (PAM), − poly­(ethylene oxide) (PEO), ,− polyethylene glycol (PEG), ,− poly­(vinyl alcohol) (PVA), poly­(dimethysiloxane) (PDMS), chitosan, polycarboxylate, polycaprolactone (PCL), cellulose acetate (CA), guar gum, and xanthan gum, as summarized in Table . The main adsorption mechanisms between clay and polymer were substantiated to be (1) cation bridges between the negative clay surface and oxygen containing functional groups of polymers (such as carboxyl); (2) hydrogen bond between the clay surface oxygens and hydroxyls or amidogens of polymers; and (3) electrostatic attraction between the negative clay surface and positive functional groups of polymers.…”

Quantitative Evaluation of the Effects of Salt Concentration and pH on the Self-Assembly of Kaolin Nanoplatelets

“…These contaminants will be transported through the strata, potentially polluting groundwater, surface water, and deep soil layers. , The microstructure of clay particles impacts the reactivity, adsorption capacity, and transport properties of the soil, which in turn affect the migration and diffusion of pollutants in the natural environment . Furthermore, pollutants will cause changes in the chemical properties of the pore water, and for clay soil, which is extremely sensitive to the hydration environment, the impact on the microstructure of clay is undoubtedly tremendous. − …”

Preparation of a Stable Superhydrophobic Mortar Surface Using a One-Step Method

“…In addition, molecular dynamics has been widely used in various disciplines, such as physics, chemistry, biology and materials. , Li et al used a combination of experimental and molecular dynamics to analyze the mechanism of chloride ion attack on cement mortars in coastal areas; the degradation process of cement-based materials in harsh environments at the microscopic level was also studied. Zhang et al observed the surface of coal with different degrees of coalification, and the variation trend of surface wettability was discussed by molecular dynamics.…”