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A novel polymeric ionic liquid (PDBA-IL-NH 2 ) using imidazolium ionic liquids with short alkyl chains as monomers and two control ionic liquids (PDBA-IL-OH and PIL-NH 2 ) were synthesized. Their inhibition properties and mechanisms were explored via surface analysis, weight loss tests, electrochemical studies, and adsorption isotherm analysis. The corrosion inhibition efficiency (CIE) of PDBA-IL-NH 2 gradually increased with increasing concentration, and the largest efficiency was 94.67% at 100 ppm. At the same concentration (50 ppm), the corrosion inhibition abilities of inhibitors were in the order of PDBA-IL-NH 2 > PDBA-IL-OH > PIL-NH 2 > IL-NH 2 . Based on the experimental investigation, the synergistic effect of electrostatic interaction, protonation, and electron donor-acceptor interaction facilitated the intensive entanglement and coverage of PDBA-IL-NH 2 with the reticulated form on the metal, and the generated densest films protected the metal from the corrosive media. Ultimately, the theoretical results of molecular dynamics simulations and quantum chemical study were in high agreement with the experimental data, which confirmed the proposed inhibition mechanisms on the microscopic scale. This study contributed valuable perspectives to the design of efficient and ecofriendly corrosion inhibitors.

Hydrate-based CO 2 storage in the ocean is considered a potential method for mitigating the greenhouse effect. Numerous studies demonstrated that NaCl exhibited the dual effects of promotion and inhibition in the nucleation and growth processes of CO 2 hydrate, whose mechanisms remain unclear. In this study, the effects of NaCl at various concentrations on the CO 2 hydrate growth and crystal are investigated. The independent gradient model based on Hirshfeld partition, electrostatic potential, and binding energy is conducted to study the interaction between ions and water molecules. The motion trajectories of ions are observed at the molecular level to reflect the impact of ion motion on hydrate growth. The results show that the influence of NaCl on hydrate growth depends on a delicate balance of dual promotion-inhibition effects. NaCl can combine more water molecules and provide a transport channel of CO 2 to promote hydrate growth at low concentrations. Meanwhile, the promoting effects shift toward inhibition with increasing NaCl concentrations. In a word, this paper proposes a novel mechanism for the dual promotion-inhibition effects of NaCl on hydrate growth, which is significant for further research on hydrate-based CO 2 storage in the ocean.

A surfactant interfacial adsorption process is highly associated with its micellization behaviors in the water phase, which is of great fundamental and practical significance in enhanced oil recovery. In this paper, the typical anionic surfactant 1-dodecanesulfonic acid sodium (DAS) and nonionic surfactants octylphenol polyoxyethylene ether- n (OP- n , n = 1, 5, and 10) are introduced to investigate their micellization behavior and interfacial adsorption process via molecular dynamics simulation. Number density profiles reveal that the additional OP5 molecules in the water phase generate the mixed micelle with DAS molecules and greatly promote its interfacial adsorption. Interaction energy calculation is employed to confirm the interaction of anionic/nonionic surfactants in the mixed micelle. Then, the radial distribution function, solvent-accessible surface area, and solvation free energy are calculated to further explore and verify the adsorption mechanism of the mixed micelle. It is found that the nonionic surfactant obviously decreases the hydrophilicity of the mixed micelle in the water phase, which should be responsible for its intensive tendency of the interfacial adsorption.

Colloidal stability of modified graphene oxide (GO) is fundamental for its practical applications. Meanwhile, most of the investigations mainly focused on the nanosheets modified by a certain amount of modifiers and neglected the effects of the modification degree, which could vary the physical and chemical properties of modified GO and significantly affect its stability in solution. To the best of our knowledge, this study initially investigated the impact of modification degrees on the colloidal stability of graphene-based amphiphilic Janus nanosheets (JGO) via both experimental and theoretical approaches. The prepared JGO, asymmetrically grafted by dodecylamine, exhibited a direct relation between the modification degree and nanosheet thickness, refractive index, electrostatic properties, hydrophobicity, and the ultimate colloidal stability. In addition, the ionic strength imposed distinctive influences on the aggregation behavior of JGO. Based on the comparison between experimental results and theoretical calculation, it was revealed that the JGO should be modeled as two-dimensional (2D) nanosheets in pure water and be treated as 3D spherical particles in electrolyte solutions for the prediction with the extended Derjaguin-Landau-Verwey-Overbeek theory.

Shale hydration is the main reason causing wellbore instability in oil and gas drilling operations. In this study, nanoscale laponite as a shale inhibitor was employed to stabilize wellbores. The inhibition property of laponite suspensions was evaluated by an immersion experiment, linear swelling measurement, and a shale recovery test. Then the shale inhibition mechanism was studied by using capillary suction time (CST) measurement, a thixotropy study, plugging performance evaluation, and related theoretical analysis. Evaluation experiment results showed that laponite had a better inhibition property than widely used inhibitors of potassium chloride (KCl) and poly(ester amine) (PA). The mechanism study revealed that integration of several factors strengthened the inhibition property of laponite suspensions. Laponite nanoparticles could plug interlayer spaces of clays by electrostatic interaction to reduce water invasion; the "house of cards" structure of laponite suspensions enables large CST values and low free water contents; the excellent thixotropy of a laponite nanofluid could allow a nanofilm to form in order to reduce water invasion into the formation; the nanoscale laponite particles could substantially reduce the shale permeability and form less porous surfaces. Furthermore, laponite could considerably decrease the filtrate volume of the drilling fluid, while KCl and PA had negative influences on the properties of the drilling fluid. This approach described herein might provide an avenue to inhibit shale hydration.