Synergy of imidazolium ionic liquids and flexible anionic polymer for controlling facilely montmorillonite swelling in water

The hydration and swelling of clay minerals in the reservoir will probably bring about serious damage to stratum. Herein, a series of imidazolium ionic liquids (ILs) with different alkyl chains were synthesized to inhibit the swelling of montmorillonite (MMT). The relationship between the inhibitory property and ILs structure was determined through detailed studies. The combination of adsorption capacity, XPS and zeta potential demonstrated that ILs successfully adsorbed on MMT replacing Na + ion. The adsorption behavior of ILs correlated well with Langmuir adsorption isotherm , implying the homogeneous monolayer adsorption. Besides, the presence of moderate amounts of flexible hydrolyzed polyacrylamide (HPAM) was favorable to improve the inhibition ability of ILs, where HPAM was adsorbed on the surface of MMT through ILs bridging, encapsulating the MMT particles. To understand inhibition mechanism in depth, the interlayer variation of dry and wet MMT and micromorphology of MMT particles were investigated to confirm the intercalation of ILs and stacking variation of MMT particles. Altogether, this study provides new insights into the structure-property relationships of imidazolium ILs and facilitates the design of excellent clay stabilizers.