On the Relation between Hamaker Constant and Contact Line Friction

S Biswas and S Chatterjee and S DasGupta and M Chakraborty, LANGMUIR, 41, 30351-30359 (2025).

DOI: 10.1021/acs.langmuir.5c03947

A deep understanding of the correlation between the Hamaker constant and contact line friction is essential for effectively optimizing fluid- substrate interactions across a wide range of critical applications. While previous studies explore these parameters separately, their direct relationship remains largely unexplored, limiting the ability to control interfacial behavior. Bridging this gap provides deeper insights into wetting dynamics, enabling the design of advanced functional surfaces. To address this, molecular dynamics (MD) simulations coupled with molecular kinetic theory (MKT) are employed to study the interfacial properties of a thin water film on a substrate with varying water- substrate interaction strengths. The substrate, designed to emulate a good wetting surface (in the vicinity of gold-water interaction), facilitates an almost monolayered thin film, allowing for a detailed analysis of solid-fluid interactions. The study examines temperature effects, revealing that the Hamaker constant remains almost conserved for a given liquid-solid system, while contact line friction decreases with increasing temperature and weaker water-substrate interactions. Finally, a fundamental correlation between the Hamaker constant and MKT parameters, particularly contact line friction, is established to enhance the fundamental understanding of the wetting framework. These findings can aid in developing efficient coatings, advanced lubricants, and optimized microfluidic systems where precise control of liquid spreading and adhesion is critical.

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