Towards construction of microscopic model for smart coating of a solid surface

TL;DR

This paper uses a density functional approach to explore wetting phase diagrams of water on chemically modified solid surfaces with grafted chain molecules, revealing complex wetting behaviors and phase transitions.

Contribution

It introduces a microscopic model for smart coatings by analyzing how grafted chains influence water wetting and phase behavior on solid surfaces.

Findings

Grafted monomers show similar prewetting diagrams to non-modified surfaces.

Grafted trimers and pentamers exhibit richer wetting behaviors.

Wetting and prewetting critical temperatures depend on grafting density and attraction strength.

Abstract

The density functional approach for classical associating fluids is used to explore the wetting phase diagrams for model systems consisting of water and graphite-like solid surfaces chemically modified by a small amount of grafted chain molecules. The water-like fluid model is adopted from the work of Clark et al. [Mol. Phys., 104, 3561 (2006)]. It very well describes the bulk water vapor-liquid coexistence. Each chain molecule consists of tangentially bonded hard sphere segments. We focus on the investigation of the growth of water film on such complex substrates and exploration of the wetting behavior. For grafted monomers, the prewetting phase diagrams are similar to the diagrams for water on a non-modified solid surface. However, for grafted trimers and pentamers, a physically much richer behavior is observed and analyzed. Trends of the behavior of the wetting temperature and the prewetting critical temperature on the grafting density and water-segments attraction are discussed in detail.