Molecular dynamics was employed to study the inhibition mechanism of vinyl lactam‐based kinetic hydrate inhibitors (KHIs). By comparing the inhibition functions of the same KHIs at different initial locations, we found that the KHI molecules on the surface of hydrate nuclei could obviously prolong the hydrate induction time and exhibited the best inhibition effect. The impacts of KHIs on the methane migration and the arrangement of H2O molecules were analyzed at the molecular level. A gas‐adsorbing mechanism for KHIs (i.e., the KHIs with an excellent gas adsorption ability could reduce the supersaturation of methane in the aqueous solution, reinforce the migration resistance of methane to the nucleus, and further inhibit the hydrate growth) was proposed. In addition, the conformations of KHI polymer molecules in the aqueous solution are closely related to their inhibitory effect, that is, stretched skeletons and well‐organized structures would maximize their inhibitory effect.

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Molecular dynamics simulations were employed here to explore the molecular mechanism for wetting and spreading behaviors of droplets on smooth and textured substrates in either the absence or presence of surfactants. In particular, we focus on the interplay among substrate hydrophobicity, roughness, and the addition of surfactants. Our simulation results indicate that substrate roughness exerts different effects on the contact angle of nanodroplets, depending on the substrate chemistry, while the presence of surfactants always changes the droplet contact angle via reducing both the vapor−liquid and liquid−solid interfacial tensions, which is independent of the substrate chemistry and roughness. In addition, our calculation results show that the addition of surfactants may lead to the wetting transition of nanodroplets on hydrophobic textured surfaces or induce the appearance of precursor film for droplet spreading on hydrophilic textured surfaces. On the spreading dynamics, we also discuss how the introduction of roughness changes the motion mode of the contact line and how the initial distribution of surfactants affects droplet spreading.

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