In order to obtain polymer microspheres for profile control and water shutoff with high temperature resistance and good swelling properties, micrometer microspheres with a double crosslinked structure were synthesized using the monomers acrylamide (AM), N-vinylpyrrolidone (NVP) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS), an initiator of potassium persulfate, a crosslinking agent of N,N-methylene bis acrylamide and zirconium acetate. The crosslinked Zr–AM/NVP/AMPS microspheres were fully characterized with several means including FT-IR, ¹³C NMR, TG-DSC and SEM. Metal crosslinking was introduced into the polymer microspheres to improve the temperature resistance by crosslinking the hydrolyzed polymer molecular chains. The results of optical microscopy and scanning electron microscopy demonstrated that a double crosslinked structure (DCS) was formed inside the Zr–AM/NVP/AMPS microspheres. It is regrettable that there is no three-dimensional network structure in the microspheres with single organic crosslinked structure (SCS). In aqueous solution, the DCS polymer microspheres were able to maintain long-term thermal stability for 150 days even at a high temperature of 140 °C. The microspheres with SCS can only be preserved for 5 days in high temperature aqueous solution at 140 °C. The TGA-DSC results indicated that the aerobic temperature capability of the DCS microspheres has been greatly improved compared with HPAM and SCS microspheres. The DCS microspheres with ultra-high temperature resistance will have broad application prospects in high temperature reservoirs.

From catanionic fluoro-/hydro-carbon mixtures of fluoroacetic acid (CF₃COOH) and tetradecyldimethylaminoxide (C₁₄DMAO) in water, viscoelastic wormlike micelles are successfully constructed which are determined by cryo-TEM measurements. It is found that the formation and rheological behavior of the wormlike micelles are greatly affected by the total concentration and mixing ratio of CF₃COOH and C₁₄DMAO as well as temperature. The driving force for the formation of wormlike micelles here is considered to be the electrostatic attractive interaction between the two molecules which is confirmed by ¹H NMR measurements. As far as we know, such wormlike micelles formed from the catanionic mixtures of fluorofatty acids and hydrocarbon surfactants have been rarely reported. Our work provides a simple method through mixing a perfluorofatty acid with a hydrocarbon surfactant to construct and understand the formation mechanism of catanionic fluoro-/hydro-carbon wormlike micelles, which should be a great advance in the fundamental research of wormlike micelles.

Improvedin situFTIR spectroscopy technology was employed to investigate the microscopic dispersion state of CO₂and ester solvent mixtures.