Polyaniline(PANI)/Ag composite nanotubes have been successfully prepared using a suitable fiber as template in the presence of H4SiW12O40 (SiW12) and silver nitrate (AgNO3) as a dopant and an oxidant, respectively. The Ag nanoparticles dispersed in the PANI nanotubes are very uniform. The structure and morphology of the product are characterized by Fourier transform infrared (FT-IR) spectrum, X-ray diffraction (XRD) pattern, scanning electron microscope (SEM), and transmission electron microscopy (TEM) images. UV rays play an important role in the polymerization. A potential formation mechanism of the PANI/Ag composite nanotubes is suggested. The average inner diameter of PANI/Ag composite nanotubes is 170 nm, which is consistent with the diameter of the template. The high surface areas, small diameter, and porous nature of the PANI/Ag composite nanotubes give significantly better performance in both gas sensitivity and time response. Moreover, the introduction of metal into organic films is effective in promoting the chemiresistor sensitivity to NH3. The gas-response to NH3 gas is examined at room temperature. Meanwhile, the reversible circulation response change of PANI/Ag composite nanotubes has a reasonable reproducibility and has more potential applications in the area of sensor development.

No abstract

To study the displacement law of polymer flooding in fluvial reservoirs, physical simulation cores are designed according to the characteristics of strong planar heterogeneity in such reservoir systems. Three different polymer solutions, namely, partially hydrolyzed polyacrylamide (HPAM), hydrophobically associating water-soluble polymer (AP-P4), and long-term shear retardant polymer (LSRP), are analyzed through oil displacement experiments. The results show that, in the simulated fluvial reservoir core model, the sweep efficiency of water flooding is about 80%, but the recovery is only about 20%, with poor oil displacement efficiency. The effects of HPAM and AP-P4 on improving sweep efficiency are poor, as they cannot effectively sweep the low- and medium-permeability areas on either side of the central core. The polymer LSRP, which has higher viscosity and better viscoelasticity, can effectively expand the sweep volume, with the sweep efficiency reaching 97.8%, but there is still the potential to greatly improve the oil displacement efficiency. The results indicate that, in fluvial reservoirs under the experimental conditions, expanding the sweep volume requires high-performance polymer solutions. The enhanced oil recovery method is required to obtain a greater oil displacement effect. The results provide a reference for the selection of displacement agents for the development of fluvial reservoirs.

No abstract

No abstract