β-Cyclodextrin/adamantane dual-modified polyacrylamide constructed via host-guest interactions for enhanced oil

β-Cyclodextrin (β-CD) has attracted considerable attention owing to its unique structure featuring an inner hydrophobic cavity and an outer hydrophilic shell. This structure enables hydrophobic molecules with appropriate sizes to enter the hydrophobic cavity and form host-guest inclusion complexes. Herein, a novel copolymer, named AANM, was synthesized from acrylamide (AM), 2-acryloylamino-2-methyl-1-propanesulfonic acid (AMPS), modified β-CD (M-β-CD) and acrylamide-adamantane (A-ADA) via redox free-radical copolymerization. The structure of AANM was characterized by Fourier transform infrared spectroscopy (FT-IR), ¹H nuclear magnetic resonance spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Experimental results revealed that the β-CD and ADA moieties may form host-guest inclusion complexes, alongside hydrogen bonding, hydrophobic association, increased chain rigidity and chain entanglement within the copolymer solution. These cooperative interactions are regarded as contributing to the outstanding thickening capacity, as well as the favorable temperature resistance and salt tolerance, of AANM in rheological behaviors. Furthermore, under the conditions of 90 °C and a salinity of 5267 mg L^-1, oil-displacement performance experiments demonstrated that AANM could achieve an incremental oil recovery of 12.5% after water flooding reached its limit. These outstanding properties demonstrate that this novel copolymer is better suited for enhanced oil recovery in harsh oilfield conditions.