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Novel hydrophilic polymers consisting of fluorene modified by alkoxyl chain were designed and synthesized via radical polymerization from acrylic acid (PAAF) or acrylamide (PAMF) in the presence of azobisisobutyronitrile. All of these polymers were good water-soluble. The photophysical behaviors of the polymers and the selectivity and sensitivity to detection metal ions were studied by UV-visible and fluorescence spectroscopy technique, and some color changes were visible to the naked eye appeared. The PAMF fluorescent probe showed good selectivity and sensitivity to detection Fe3+ (2.4 × 10−7 mol/L) and PAAF exhibited good selectivity and sensitivity to detection Fe2+ (1.5 × 10−6 mol/L) and Cu2+ (5 × 10−7 mol/L) in water. [ABSTRACT FROM AUTHOR]

Nanomaterials can be used to emulsify and reduce the fluid viscosity, reduce pore pressure, and increase injection volume. Therefore, nanomaterials have a great potential in the enhanced oil recovery. However, the current research on nanooil flooding materials mostly focuses on the evaluation of the oil-displacing effect, and the lack of research on the size of the oil-displacing materials for tight oil is obvious. In this work, 1T phase molybdenum disulfide nanosheets were prepared by one-step hydrothermal method, which were further modified with CTAB powders to obtain MoS2-CTAB nanosheet powders. Combined with SEM, TEM, and AFM methods, the nanosheets were optimized based on the appearance and morphology. The stability, wetting reversal, and oil displacement capacity of selected nanosheets were tested. The results show that the best experimental condition to synthesize small-sized molybdenum disulfide is 200°C in the weak acid environment through 12 h. Due to the steric hindrance effect of the CATB molecule, the size and interlayer gap of MoS2 nanosheets increased slightly after modification. The layer gap reaches to 0.7 nm, and the number of stacked layers is 3~4 layers. Strong Raman bands are observed at 137 cm-1, 291 cm-1, and 391 cm-1, which indicates that the synthesized product is 1T MoS2. The modified MoS2 nanosheets in aqueous solution have better dispersion than the unmodified one. After the Zeta test, it was found that the absolute value after modification became lower, indicating that the modification of nano-MoS2 was effective. Moreover, the MoS2-CTAB can complete the wetting reversal within 4 h and make the interfacial tension reach 0.89 mN/m at 0.005 wt%, which greatly reduces the capillary pressure. The enhanced oil recovery effect of MoS2-CTAB nanosheets increased by 85.7% compared with that before modification and 62.5% higher compared with pure surfactant. [ABSTRACT FROM AUTHOR]

Nanomaterials can be used to emulsify and reduce the fluid viscosity, reduce pore pressure, and increase injection volume. Therefore, nanomaterials have a great potential in the enhanced oil recovery. However, the current research on nanooil flooding materials mostly focuses on the evaluation of the oil-displacing effect, and the lack of research on the size of the oil-displacing materials for tight oil is obvious. In this work, 1T phase molybdenum disulfide nanosheets were prepared by one-step hydrothermal method, which were further modified with CTAB powders to obtain MoS2-CTAB nanosheet powders. Combined with SEM, TEM, and AFM methods, the nanosheets were optimized based on the appearance and morphology. The stability, wetting reversal, and oil displacement capacity of selected nanosheets were tested. The results show that the best experimental condition to synthesize small-sized molybdenum disulfide is 200°C in the weak acid environment through 12 h. Due to the steric hindrance effect of the CATB molecule, the size and interlayer gap of MoS2 nanosheets increased slightly after modification. The layer gap reaches to 0.7 nm, and the number of stacked layers is 3~4 layers. Strong Raman bands are observed at 137 cm-1, 291 cm-1, and 391 cm-1, which indicates that the synthesized product is 1T MoS2. The modified MoS2 nanosheets in aqueous solution have better dispersion than the unmodified one. After the Zeta test, it was found that the absolute value after modification became lower, indicating that the modification of nano-MoS2 was effective. Moreover, the MoS2-CTAB can complete the wetting reversal within 4 h and make the interfacial tension reach 0.89 mN/m at 0.005 wt%, which greatly reduces the capillary pressure. The enhanced oil recovery effect of MoS2-CTAB nanosheets increased by 85.7% compared with that before modification and 62.5% higher compared with pure surfactant. [ABSTRACT FROM AUTHOR]

The synthesis of a series of side-chain π-conjugated fluorene and terpyridine-functionalized hydrophilic poly(acrylamide) hydrogels via radical random copolymerization was reported. Based on the coordination of terpyridines and europium (III) ions, the dual-network hydrogels containing chemical covalent cross-linking bonds and metallo-supramolecular cross-linking bonds were prepared. Their structures and properties were studied systematically via NMR, IR, SEM, UV–vis absorption spectra, photoluminescence spectra and rheological. The photophysical properties showed that there was Förster energy transfer from conjugated chromophores (emission wavelength at 359–435 nm) to the europium emitter. The water content and the ratio of the energy donor and acceptor in the hydrogels make important influences on the energy transfer and then the emission color of the resulting dual-network hydrogel can be regulated from blue to red via controlling the degree of the energy transfer. Meanwhile, the dual-network hydrogels exhibited small and uniform pore structure and good mechanical properties with large storage and loss moduli. [Display omitted] • A series of side-chain π-conjugated fluorene and terpyridine-functionalized hydrophilic poly(acrylamide) was prepared. • The dual-network hydrogels were constructed based on chemical cross-linking and metallo-supramolecular cross-linking. • The water content and the ratio of the donor and acceptor make heavy influences on the energy transfer and emission color. • The dual-network hydrogels exhibited small and uniform pore structure and good mechanical properties. [ABSTRACT FROM AUTHOR]