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Considerable luminescence dissymmetry factor (g lum) is vital for application implementation of circularly polarized luminescence (CPL) materials. Moreover, a dual CPL switch has promising prospects in high-security encryption and sensor devices. Herein, we designed and synthesized an emissive chiral nematic liquid crystal (N*-LC) by doping a luminescent chiral additive (NO2-CS-C6-Chol) into a nematic liquid crystal (5CB). The helical assembly structure produced by inducing the formation of N*-LC endows the prepared emissive N*-LC with a larger g lum value. With the increase of the doping concentration from 1 to 10 wt %, the helical pitch (P) of N*-LC gradually decreases from 25.48 to 3.92 μm. The corresponding g lum value increases first, reaches the maximum value (−0.38) at 6 wt %, and then decreases slightly. Further, the prepared emissive N*-LC doped with 6 wt % NO2-CS-C6-Chol is injected into an indium-tin oxide (ITO)-coated LC cell, to which a direct current (DC) electric field is applied. The g lum value can be repeatedly shuttled between the “on” and “off” state by adjusting the applied voltage. Meanwhile, owing to the inherent thermal dependence of the liquid crystal phase structure, the g lum value can also be switched between the on and off state by regulating the temperature. Therefore, an electrically controlled and thermocontrolled dual CPL switching device is successfully constructed.

An emulsion that can be fast and spontaneously formed in reservoirs will be greatly beneficial to the oil recovery improvement in low-permeability reservoirs. Herein, an ultralow interfacial tension spontaneous emulsification (SE) system consisting of a novel anionic alkyl polyglucoside sodium hydroxypropyl sulfonate surfactant (APGSHS) surfactant and a cationic cetyltrimethylammonium bromide (CTAB) surfactant was proposed and studied for low-permeability reservoirs. The spontaneous emulsions were characterized in terms of morphology and size distribution of droplets. Multiple-light scattering method was applied to evaluate the stability and dynamic instability mechanism of O/W emulsions. In addition, the viscoelasticity and shear-recovery performance of emulsions were also investigated. The combined SE systems can form the spontaneous emulsions via once bottom-up cycle, and the average droplets size of optimum emulsion with 6:4 molar ratio is ∼0.2 μm, which is small enough to migrate in the porous media at low-permeability reservoirs. Besides, the coalescence and creaming of oil droplets, as well as clarification thickness, are well-deferred. The viscoelasticity and shear-recovery capacity can also be improved with the presence of combined SE systems. The efficient interfacial activity and emulsion performances can be attributed to the strong electrostatic attraction between anionic and cationic surfactants, which enables the formation of a tighter arrangement film on an oil/water interface. Ultimately, the core flooding experiments show that the optimum SE system can effectively enhance oil recovery by 14.14% of the initial oil in place and significantly decrease the injected pressure. Hence, the newly formulated spontaneous emulsification system with anionic/cationic surfactants exhibit remarkable performances and can be used as an ideal candidate for EOR in low-permeability reservoirs.

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How to improve the performance of circularly polarized luminescence (CPL) materials in film state is a significant subject to realize its further application. Herein, we synthesized the side-chain chiral fluorescent...