Structure of methanol sub-monolayer on functionalized graphite at temperatures below the triple point

Molecular Insights into the Effect of Temperature and Functional Groups on the Nonwetting, Prewetting, Partial Wetting, and Complete Wetting Transitions of Ethanol on Graphite

“…Among them, methanol and ethanol are widely chosen to study adsorption phenomena since their properties fall between those of nonpolar fluids and water. ,− Early experimental works studied a monolayer film of both methanol and ethanol on graphite at low temperatures (30–215 K) using X-ray diffraction. The results revealed a zigzag chain structure of H bonds between their molecules on the surface. , In the case of methanol and propanol, due to the balance between the intermolecular energy, the energy between the fluids, the graphite surface, and the temperature, more phase transitions were revealed. , This behavior was later microscopically explained by molecular simulations. , Monolayer adsorption of methanol molecules on the confined surface between two graphene layers was observed by molecular dynamics. At low temperatures (160 K), methanol formed as rings, which grew with increased loading and then transformed into a string .…”

“…The cutoff radius was 3nm, and the periodic boundary condition was applied at the boundaries in the x and y directions parallel to the surface. The calculations of the surface excess, isosteric heat, and local density distributions can be found elsewhere. ,, …”

“…Using a Grand Canonical Monte Carlo (GCMC) simulation, the monolayer of methanol adsorption on a graphite surface grafted with functional groups at 160 K (below the triple point of bulk methanol, 175 K) was investigated. The isotherm exhibited four transitions: (i) the transition on functional groups to be saturated by adsorbate, (ii) ring spreading on the basal plane, (iii) ring-to-string transition, and (iv) the densification of the string …”

“…17,18 This behavior was later microscopically explained by molecular simulations. 19,20 Monolayer adsorption of methanol molecules on the confined surface between two graphene layers was observed by molecular dynamics. At low temperatures (160 K), methanol formed as rings, which grew with increased loading and then transformed into a string.…”

“…The isotherm exhibited four transitions: (i) the transition on functional groups to be saturated by adsorbate, (ii) ring spreading on the basal plane, (iii) ring-to-string transition, and (iv) the densification of the string. 20 Furthermore, the wetting and nonwetting behavior of polar and nonpolar fluids on graphite surfaces has attracted much interest from experimental 21−23 and theoretical research. 24−26 In this study, we present the adsorption isotherm behavior and the parametric diagram of an adsorbatein particular, ethanolfor its wetting transitions, such as complete wetting, partial wetting, prewetting, and nonwetting depending on the temperature and substrate (Figure 1).…”