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Environmental-friendly epoxy (EP) composite coatings are regarded as distinguished candidates for preventing metal corrosion. In this paper, we synthesized a novel GO-PDA-MoS 2 /EP nanocomposite coating system by modifying dopamine (PDA) functionalized graphene oxide (GO) with MoS 2. Here, the effect of different MoS 2 additions on the corrosion resistant properties of coatings was investigated by altering the ratio of MoS 2 to GO-PDA via electrochemical measurements, long-duration immersion experiments, and water contact angle tests. The results indicated that 0.3 wt.% MoS 2 can substantially enhance the interfacial compatibility between EP and GO-PDA and the GO-PDA-MoS 2 -0.3 wt.%/EP coating presented optimum corrosion resistant properties. Specifically, the impedance modulus (|Z|) of the GO-PDA-MoS 2 -0.3 wt.%/EP coating still reached 2.36 × 107 Ω·cm2 after 30 days immersed, which was two orders of magnitude higher than pure EP coatings. This work demonstrates a novel economical and environmental scheme that MoS 2 can be employed to enhance the corrosion resistant properties and improve the interfacial interactions of EP coatings. [Display omitted] [ABSTRACT FROM AUTHOR]

For chemical flooding, choosing suitable surfactant and polymer mixture to optimize the viscosity and interfacial tension is an important procedure for preparing the combination flooding system. In this work, a systematic study was conducted on the properties of the surfactant/polymer mixed solution, involving viscoelasticity, oil/water interfacial tension and oil displacement efficiency. Zwitterionic-anionic surfactant mixture (HDPS-SDS) was chosen to show the effect of concentration and micelles type. Partially hydrolyzed polyacrylamide (HPAM) and hydrophobically associating polymer (HPOC) were selected to show the effect of polymer concentration and type. It has been found that for polymer solutions, adding HDPS-SDS reduces the oil/water interfacial tensions to the magnitude of 10−2 mN·m−1, but negative synergistic effect for spherical micelles and positive synergistic effect for wormlike micelles on viscosity are observed. For wormlike micelles solutions, adding HPAM or HPOC increases the viscosity. Moreover, the positive synergistic effect on viscosity by HPOC is far stronger than that of HPAM, and the viscosity of wormlike micelle solution can be reinforced by adding a small amount of HPOC. The synergistic effect on viscosity will also affect the oil displacement efficiency of the surfactant/polymer mixed system. For example, the enhanced oil displacement efficiency E of surfactant/polymer flooding unexpectedly reduces with adding spherical micelles formed by low concentration HDPS-SDS to 1500 mg L−1 HPOC solutions. Whereas the enhanced oil displacement efficiency E of wormlike micelles/polymer flooding reaches 28.8% with adding 800 mg L−1 HPOC to 5500 mg L−1 HDPS-SDS wormlike micelles solutions. [Display omitted] • The effect of surfactant concentration and micelles type, polymer concentration and type on viscoelasticity, oil/water interfacial tension and oil displacement efficiency of the surfactant/polymer mixed solution were studied systematically. • For polymer solutions, adding HDPS-SDS reduces the oil/water interfacial tensions to the magnitude of 10−2 mN·m−1, but negative synergistic effect for spherical micelles and positive synergistic effect for wormlike micelles on viscosity are observed. • For viscoelastic surfactant solutions, adding HPAM or HPOC all increase the viscosity. Moreover, the viscosity of viscoelastic surfactant solution can be reinforced by adding a small amount of HPOC. • The synergistic effect on viscosity will also affect the oil displacement efficiency of the surfactant/polymer mixed system. [ABSTRACT FROM AUTHOR]

The oil flow behaviors in inorganic and organic nanopores are still unclear due to the effects of complex surface properties on boundary slip velocity and effective oil viscosity, such as surface roughness and various wettability. In this work, the oil flow enhancement factor and apparent permeability model are derived by coupling slip length and effective viscosity based on the no-slip Hagen–Poiseuille equation. The effects of the oil–wall molecular interactions, pore radius, fractal surface roughness and heterogeneous wettability are considered, and the heterogeneous wettability is caused by the trapped gas between rough elements. The results show that (1) the enhancement factor ranges from 10 − 1 to 108 with contact angle ranging from 0 ∘ to 180 ∘ , and gradually tends to 1 with an increasing pore radius. Additionally, the flow enhancement factor and apparent permeability increase with an increasing contact angle; (2) The surface roughness can increase or decrease apparent contact angles of oil droplet on water-wetting or oil-wetting surface, respectively, and the increasing or decreasing value of contact angle increases with an increasing fractal dimension. Therefore, as rough fractal dimension increases, the enhancement factor and apparent permeability decrease in oil-wetting pores and increase in water-wetting pores; (3) With an increasing trapped gas content, because the surface becomes more oil-nonwetting that leads to the larger slip length and smaller effective viscosity, the enhancement factor and apparent permeability increase. This model has certain significance for the study of liquid flow behaviors in nanopores with rough surface and heterogeneous wettability, and can be used to fit the results measured by experiments by changing the fractal dimension and trapped liquid content. [ABSTRACT FROM AUTHOR]

Interfacial tension and emulsification are important to enhance oil recovery. There is almost none quantitative research on their correlation for Daqing crude oil. Experiments are performed to find out the correlation between different interfacial tension, emulsification and chemical flooding oil displacement efficiency. The authors changed the structure of surfactant to make characteristics of interfacial tension different significantly and build the relationship between interfacial tension parameters and chemical flooding oil displacement efficiency by physical simulate experiments. The ultralow interfacial tension index (expressed by S) is established by orthogonal test and actual significance of interfacial tension curves. The fitting formula between S and chemical flooding oil displacement efficiency (E) is: E = 0.856 ln(S) + 13.849. The emulsifying ability includes two aspects O/W and W/O. Authors changed the structure of surfactant to make characteristics of ASP systems have similar interfacial property but different emulsification property. Compared the oil displacement efficiency of these systems, built the correlation between emulsifying ability and chemical flooding oil displacement efficiency for Daqing crude oil. This paper established the index of ultralow interfacial tension and emulsification, and summed up the formulae based on that with oil displacement efficiency. The quantitative evaluation of ASP system can optimize the existing evaluation methods and deepen understandings on flooding mechanism for Daqing crude oil. [ABSTRACT FROM AUTHOR]

Mesoderm is derived from the primitive streak. The rostral region of the primitive streak forms the somitic mesoderm. We have previously shown the developmental origin of each level of the somitic mesoderm using DiI fluorescence labeling of the primitive streak. We found that the more caudal segments were derived from the primitive streak during the later developmental stages. DiI labeled several pairs of somites and showed the distinct rostral boundary; however, the fluorescence gradually disappeared in the caudal region. This finding can be explained in two ways: the primitive streak at a specific developmental stage is primordial of only a certain number of pairs of somites, or the DiI fluorescent dye was gradually diluted within the primitive streak by cell division. Here, we traced the development of the primitive streak cells using enhanced green fluorescent protein (EGFP) transfection. We confirmed that, the later the EGFP transfection stage, the more caudal the somites labeled. Different from DiI labeling, EGFP transfection performed at any developmental stage labeled the entire somitic mesoderm from the anterior boundary to the tail bud in 4.5-day-old embryos. Furthermore, the secondary neural tube was also labeled, suggesting that not only the somite precursor cells but also the axial stem cells were labeled. [ABSTRACT FROM AUTHOR]

Abstract: Injected chemical flooding systems with high salinity tolerance and fast‐dissolving performance are specially required for enhancing oil recovery in offshore oilfields. In this work, a new type of viscoelastic‐surfactant (VES) solution, which meets these criteria, was prepared by simply mixing the zwitterionic surfactant N‐hexadecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propane sulfonate (HDPS) or N‐octyldecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propane sulfonate (ODPS) with anionic surfactants such as sodium dodecyl sulfate (SDS). Various properties of the surfactant system, including viscoelasticity, dissolution properties, reduction of oil/water interfacial tension (IFT), and oil‐displacement efficiency of the mixed surfactant system, have been studied systematically. A rheology study proves that at high salinity, 0.73 wt.% HDPS/SDS‐ and 0.39 wt.% ODPS/SDS‐mixed surfactant systems formed worm‐like micelles with viscosity reaching 42.3 and 23.8 mPa s at a shear rate of 6 s−1, respectively. Additionally, the HDPS/SDS and ODPS/SDS surfactant mixtures also exhibit a fast‐dissolving property (dissolution time <25 min) in brine. More importantly, those surfactant mixtures can significantly reduce the IFT of oil–water interfaces. As an example, the minimum of dynamic‐IFT (IFTmin) could reach 1.17 × 10−2 mN m−1 between the Bohai Oilfield crude oil and 0.39 wt.% ODPS/SDS solution. Another interesting finding is that polyelectrolytes such as sodium of polyepoxysuccinic acid can be used as a regulator for adjusting IFTmin to an ultralow level (<10−2 mN m−1). Taking advantage of the mobility control and reducing the oil/water IFT of those surfactant mixtures, the VES flooding demonstrates excellent oil‐displacement efficiency, which is close to that of polymer/surfactant flooding or polymer/surfactant/alkali flooding. Our work provides a new type of VES flooding system with excellent performances for chemical flooding in offshore oilfields. [ABSTRACT FROM AUTHOR]

• Three N-substituted methyl ethylenediamine derivatives TDA, PTA, and HTA, have been proved to be good corrosion inhibitors for 20# steel in 1 M HCl solution. • The inhibition efficiency following the order: TDA

Abstract: We report in this work the microstructure, rheological behavior and thermal stability about the gel emulsions formed in water, oil and Gemini surfactant sodium didecamino cystine (SDDC) systems. Optical microscopy results indicate that the oil droplets are polydisperse and closely packed in the gel emulsions. Dynamic rheological measurements reveal that these gel emulsions exhibit typical viscoelastic character of gel-like structure and the viscoelasticity increase along with raising the SDDC concentration. Further analysis by using the cooperation theory of flow demonstrates that the gel emulsion with stronger cohesive interactions and lower number of interaction units are obtained by increasing the SDDC concentration, which enhance the emulsion stability in slowing down emulsion creaming and coalescence. It has been found that the gel emulsion produced by Gemini surfactant SDDC is shown a superior thermal stability upon heating at 50°C compared with the gel emulsion produced by the monomeric surfactant sodium laurate (SL). [Copyright &y& Elsevier]

Abstract: We report in this work on the scaling behavior of wormlike micelles formed in a series of mixed systems of oppositely charged surfactants, including sodium decanote (SD)/hexadecyltrimethylammonium bromide (CTAB), sodium laurate (SL)/hexadecyltrimethylammonium bromide, sodium didecaminocystine (SDDC)/hexadecyltrimethylammonium bromide, and sodium dilauraminocystine (SDLC)/hexadecyltrimethylammonium bromide. Steady and dynamic rheological measurements were performed to characterize these wormlike micelles. The scaling behavior for these systems at various mixing ratios was systematically investigated and was compared with that given by the Cates model. It was found that the Cates law can be applied in these systems simply by manipulating the mixing ratio or the surfactant structure. Energetic analysis demonstrates that the scaling behavior of wormlike micelles in nonequimolar mixed cationic and anionic surfactant systems can be close to that predicted by the Cates model, if the electrostatic contribution is below a threshold value. [Copyright &y& Elsevier]

Abstract: Two types of Gemini surfactants containing a disulfide bond in the spacer, sodium dilauroyl cystine (SDLC) and sodium didecamino cystine (SDDC), were synthesized, and their surface properties and aggregation behavior in aqueous solution were studied by means of surface tension measurements, dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescence. During the transition of the Gemini surfactants to their corresponding monomers through the reduction of disulfide bonds, the surface tensions of their aqueous solutions, as well as their aggregation behavior, changed greatly. The reduction of SDLC and SDDC led to disruption of the vesicle, and the oxidation of corresponding monomers to Gemini surfactants led to vesicle re-formation. These results demonstrated the control of surface properties and aggregation behavior by the reversible transition between the Gemini surfactant and its monomer via reduction/oxidation reactions. [Copyright &y& Elsevier]

Hepatitis B virus (HBV) infection is a crucial public health issue and a major cause of liver disease, such as cirrhosis and hepatocellular carcinoma. At present, orally administered small molecule drugs, such as nucleoside / nucleotide analogues, are recommended as the first‐line treatment for HBV. However, the therapeutic efficacy of these drugs is hindered by off‐target toxicity caused by the whole‐body permeation distribution of these oral drugs. As an emerging drug delivery technology, systemically administered nanocarriers can enhance the aqueous solubility and stability of encapsulated drugs, prolong circulation times, and deliver them efficiently to the liver, showing great promise for increasing the safety and efficacy of small molecule drugs. Furthermore, nanocarriers also accelerate the clinical translation of new therapies, such as nucleic acids and vaccines. This review article highlights the progress of nanoparticle delivery systems in anti‐HBV therapeutics and discusses the opportunities and challenges for the future development of anti‐HBV nanotherapeutics. [ABSTRACT FROM AUTHOR]

The selective oxidation of alcohols has drawn significant attention in heterogeneous catalysis with the increasing use of Pickering interfacial catalysis (PIC) for green transformations of alcohols. However, it is still highly desirable to design and develop a solid catalyst with easy separation and recycling, made from abundant resources through a simple synthesis route, for the selective oxidation of alcohols. In this study, ferrite nanoparticles, synthesized via a hydrothermal process, were employed to act as a stabilizer and catalyst in PIC for the oxidation of benzyl alcohol using H2O2. The ferrite nanoparticles exhibited higher catalytic performance in PIC than in acetonitrile. The turnover number (TON) of the nanocatalyst in PIC was found to be 1.5–4 times higher than that in acetonitrile, and the reaction constant in PIC (kPIC = 0.712 h−1) was almost twice that in acetonitrile (kCH3CN = 0.310 h−1) for MnFe2O4 nanoparticles. Moreover, other alcohols could also be oxidized with moderately high conversion and selectivity in PIC. Significantly, the ferrite nanocatalyst could be easily separated from PIC using a magnet for reuse, achieving 88% BzOH conversion after five cycles. The use of hazardous organic solvents was avoided in PIC, making it a more advanced, green and sustainable reaction system. [ABSTRACT FROM AUTHOR]

In this paper, the aluminum gel with polymeric aluminum chloride (PAC) as the gelling agent and carbamide as a catalyst were investigated. The gelling regularities were studied, and its gelling performance was evaluated under high temperature and high salinity. The results showed that the basicity, mass fraction of PAC and carbamide, temperature, and salinity significantly influenced the formation of the gel. The gel exhibited exceptional thermal stability and gel strength under high temperature and salinity conditions. The results indicated that when the aluminum gel was prepared with 8 wt% PAC and 1 wt% carbamide and dissolved in brine with a salinity of 110,000 mg/L, the dehydration rate was less than 1 wt% after being aged for 180 days at 130 °C. Furthermore, the gel strength, elasticity, and yield stress increased with the rise in salinity. The experimental results showed that the aluminum gel is highly significant in plugging reservoirs with high temperature, high salinity, and low permeability. [ABSTRACT FROM AUTHOR]

Water and gas channelling are important limiting factors for the development of fractured reservoirs. A three-phase foam system stabilized by fly ash is optimized as a sealing system to plug fractured reservoirs. The analysis covers the interfacial properties, particle adsorption effect and rheological properties to reveal the stabilization mechanism of fly ash on the three-phase foam. A sealing experiment was performed to evaluate the sealing capacity of the optimized foam system on fractured reservoirs using a natural core with artificial fracture. Results showed the optimized foam system, which consists of 0.5 wt% AOS + 4 wt% suspending agent + 8 wt% fly ash, has excellent stability with a foam half-life of more than 7 days. The adsorption of fly ash particles on the surface of the liquid film can reduce surface tension and improve viscoelasticity of the bubble films, prevent drainage of the liquid layer effectively and delay the aggregation and rupture speed of foam. The optimized fly ash three-phase foam can plug the channelling path of fractures in reservoirs efficiently with a sealing effect 20 times more than that of the conventional foam without particles. Hence, the optimized fly ash three-phase foam is an effective sealing system for plugging fractured reservoirs. [ABSTRACT FROM AUTHOR]

Detrital composition of sandstone is the most important data for siliciclastic studies including sandstone classification, provenance analysis, oil and gas exploration. A large amount of detrital composition data has accumulated over the past decades, however, they are scattered in publications without unified standards. Here we constructed a global dataset of detrital components of sandstones from 646 peer‐reviewed publications using Gazzi‐Dickinson method. A total of 19,861 samples from Precambrian to Quaternary are involved in this dataset. For each sample, we present details on reference information, geographic information, geological background, depositional age and the original data. It is a high‐quality dataset for the information on each sandstone sample from different studies which was standardized. The dataset can be used widely, such as for stratigraphic comparison, provenance analysis, exploring the general laws of the source‐to‐sink process and geological engineering. [ABSTRACT FROM AUTHOR]

• The mass transfer processes and localized corrosion mechanisms of different pipeline defects (pitting depression and welded joint with weld reinforcement) were investigated under flow accelerated corrosion. • The swirling vortex and vertical jet impact induced by reflux interference can promote the process of localized corrosion. • The galvanic corrosion intensity of welded joints with weld reinforcement and pitting depression was evaluated. • The FGHAZ in the HAZ at the trailing edge of the weld endures the impact of the impinging jet and becomes the preferred region for corrosion failure. The pipeline defects of flow accelerated corrosion (FAC) on the corrosion behaviors and localized corrosion mechanisms on different locations of the depressions and the welded joint with weld reinforcements were investigated using wire beam electrode (WBE) techniques and fluid dynamics simulations. The results revealed that the swirling vortex inside the depression and the local jet impact by the fluid separation in the weld reinforcement can accelerate the localized corrosion. Also, the depressed upper and trailing edge regions and the weld toes on both sides of the weld reinforcement experience considerable pressure fluctuations, enhancing interfacial mass transfer processes and inducing cavitation for severe localized corrosion failure. Furthermore, the galvanic corrosion strength factor (g) indicated an enhanced susceptibility of localized corrosion in depression and welded joints with weld reinforcement. [ABSTRACT FROM AUTHOR]

Previous studies have found that ionic surfactant micelles can induce depletion forces between oil droplets, whereas the depletion forces induced by nonionic surfactant micelles cannot be measured. Nonionic surfactants are usually mixed with ionic surfactants to induce depletion forces. Here, we report that mixing of nonionic polymer micelles and inorganic salt is also an effective method for inducing depletion between oil droplets. Optical tweezers are used to measure the interaction forces between oil droplets in the aqueous solution of polyoxyethylene–polyoxypropylene–polyoxyethylene nonionic polymer. Without salts, there is no depletion force between oil droplets regardless of whether the concentration of polymer is above or below the critical micelle concentration (CMC). This result is consistent with literature that the oil drops adsorbed by the nonionic polymers were stable against coalescence. However, the depletion force between oil droplets generates when NaCl is added, and the concentration of Pluronic F127 is above or equal to the CMC. This suggests that salts can enhance the depletion force induced by nonionic polymer micelles. These findings have significant implications for the stability of emulsions in the food, oilfield, and medicine industries. [ABSTRACT FROM AUTHOR]

Sepsis is defined as a life-threatening organ dysfunction caused by excessive formation of reactive oxygen species (ROS) and dysregulated inflammatory response. Previous studies have reported that shikonin (Shik) possess prominent anti-inflammatory and antioxidant effects and holds promise as a potential therapeutic drug for sepsis. However, the poor water solubility and the relatively high toxicity of shikonin hamper its clinical application. To address this challenge, we constructed Zn2+-shikonin nanoparticles, hereafter Zn-Shik-PEG NPs, based on an organic-inorganic hybridization strategy of metal-polyphenol coordination to improve the aqueous solubility and biosafety of shikonin. Mechanistic studies suggest that Zn-Shik-PEG NPs could effectively clear intracellular ROS via regulating the Nrf2/HO-1 pathway, meanwhile Zn-Shik-PEG NPs could inhibit NLRP3 inflammasome-mediated activation of inflammation and apoptosis by regulating the AMPK/SIRT1 pathway. As a result, the Zn-Shik-PEG NPs demonstrated excellent therapeutic efficacies in lipopolysaccharide (LPS) as well as cecal ligation puncture (CLP) induced sepsis model. These findings suggest that Zn-Shik-PEG NPs may have therapeutic potential for the treatment of other ROS-associated and inflammatory diseases. [ABSTRACT FROM AUTHOR]

• A compound system composed of Interfacially Active Polymer and Emulsifying Viscosity Reducer was proposed. • IAP-EVR compound system can form stable emulsion with low IAP and EVR concentrations. • The emulsifying viscosity reduction and emulsion stabilization of IAP-EVR compound system was evaluated. • Supramolecular network was formed by IAP-EVR compound system. • the oil displacement mechanism of IAP-EVR compound system were clarified. Chemical Cold Heavy Oil Production (CCHOP) represents an effective approach to exploit heavy oil by injecting Oil Viscosity Reducer (OVR). However, the challenge lies in the crossflow of traditional OVR through high permeability channels in heterogeneous heavy oil reservoirs. a supramolecular compound system comprising Interfacially Active Polymer (IAP) and Emulsifying Viscosity Reducer (EVR) were proposed as a novel CHHOP agent to address this problem. A series of experiments were conducted to investigate the heavy oil displacement performance and mechanism of the IAP-EVR compound system, including assessments of heavy oil emulsification, emulsion stability, rheological properties, single-core oil displacement, and heterogeneous microscopic oil displacement. The results demonstrate that a stable O/W emulsion can be formed with the 0.1 wt% IAP-0.3 wt% EVR compound system under a low mixing rate of 200 rpm. The emulsion exhibits only an 8.0% dewatering rate and a low TSI value of 0.8. Moreover, the compound system effectively reduces the heavy oil viscosity from 1000 mPa·s to 325.7 mPa·s, facilitating the emulsification of the remaining oil after water flooding and enhancing its flowability, thus improving oil displacement efficiency. Additionally, the 0.1 wt% IAP-0.3 wt% EVR compound system increases the solution viscosity to 600 mPa·s, leading to a low W/O mobility ratio, which enhances the swept volume. Supramolecular association is identified as a crucial mechanism for stabilizing the emulsion and increasing the solution viscosity, as evidenced by a high elastic modulus of 144.7 mPa and a transition area observed in the viscosity-shear rate curve. In comparison to HPAM and IAP, the 0.1 wt% IAP-0.3 wt% EVR compound system yields higher oil recoveries of 21.84 %OOIP in the single core experiment. Moreover, noticeable emulsification is observed in the produced fluid, and oil recoveries of 89.85 %OOIP and 92.98 %OOIP are achieved in high and low permeable areas, respectively, in the heterogeneous microscopic model. These results indicate a mechanism that enhances both the swept volume and oil displacement efficiency. Overall, the findings of this study provide a laboratory foundation for the promising application of the IAP-EVR compound system in heterogeneous heavy oil reservoirs. [ABSTRACT FROM AUTHOR]

Recently, oil-water separation materials with special wettability surfaces have attracted intense attention. In this work, amphiphilic magnetic nanoparticles of Fe3O4@TiO2 are prepared by the homogeneous precipitation method. The prepared nanoparticles are characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Dynamic light scattering, Zeta potential and contact angle. The prepared magnetic nanoparticles can effectively separate the simulated oily wastewater prepared with 0# diesel. The oil removal performance with magnetic nanoparticles Fe3O4@TiO2 is evaluated by a handheld oil meter after rotating at 250 rpm for a certain time. Results show that the prepared material has the best oil-water separation performance and maintains high magnetism when the weight ratio of TiO2 is 80%. When the dosage is 0.125% (w/v), the oil removal rate is up to 97% after 30 minutes of addition. These prepared materials are suitable for oil-water separation under neutral and acidic conditions and have good recycling performance. This indicates that the prepared amphiphilic magnetic nanoparticles have practical applications in the treatment of oily wastewater. [ABSTRACT FROM AUTHOR]

The nanoscale thermal effect of ferrimagnetic vortex-domain iron oxide nanorings (FVIOs) was measured when exposed to an alternating magnetic field. A molecular temperature probe (fluorescein isomer I, FI) was attached to a thermo-sensitive molecule (4,4′-Azobis (4-cyanovaleric acid, AZO), then the molecule was bound to the nanoparticle surface through poly (ethylene glycol) (PEG, Mw = 1000, 2000, 5000 Da) spacers of different molecular weights. The magnetothermal effect induced the thermal decomposition of AZO driving the release of FI which was monitored by the photoluminescence method. It was found that the effective local temperature (Teff) decreased with the increase of Mw (PEG) and increased with the rise in field amplitudes B, and the temperature was found in a linear relationship with the applied magnetic field at all distances. The significant local heating temperature (T) rose to 60.3 °C when d = 0 of FVIOs, where d is the distance of the AZO-FI end group to the surface, while it fell exponentially with the increasing distance. The nanoscale thermal effect of the 20 nm superparamagnetic iron oxide nanoparticles (SPIOs) was also studied. The results revealed that FVIOs have much higher nanometer local heat than SPIOs for all the applied magnetic field amplitudes. These findings were then applied in the enzyme activity regulation experiment of FVIOs and SPIOs. The results indicated that glucose oxidase (GOD) had higher enzyme activity after nano-magnetothermal stimulation of FVIOs. [ABSTRACT FROM AUTHOR]

The influence of salt and temperature on the viscosity of a hydrophobically modified polyacrylamide-based (PAM-based) novel functional polymer (RH-4) was investigated. To study the viscosifying mechanism in brine solution, scanning electron microscope (SEM) was applied to observe the network microstructures of polymer solution. The solution apparent viscosity behaviors of the RH-4 polymer are studied as functions of concentrations, pH value, salt types and amount, microscopic morphology. The viscoelasticity of aqueous solutions of RH-4 polymer changed with shear rate under high salinity condition. Additionally, the influence of temperature on the apparent viscosity of RH-4 polymer was investigated. The results showed that the viscosity decreased at lower salt concentrations and increased at higher salt concentrations. The SEM results show that the network structures of RH-4 polymer become much more condense at high salinity, which lead to the increasing its apparent viscosity. When the salinity reaches 80,000 mg/L, thickening ability of the system is the strongest. With the rise in temperature, the viscosity of polymer solutions with various concentrations decreases slightly except for the two concentrations of 1000 mg/L and 1100 mg/L, their viscosity increases with the increasing of temperature. The thickening tendency is enhanced by high salinity and high temperature, which makes it more promising for EOR. [ABSTRACT FROM AUTHOR]

Cancer immunotherapy has shown promising therapeutic results in the clinic, albeit only in a limited number of cancer types, and its efficacy remains less than satisfactory. Nanoparticle-based approaches have been shown to increase the response to immunotherapies to address this limitation. In particular, magnetic nanoparticles (MNPs) as a powerful manipulator are an appealing option for comprehensively regulating the immune system in vivo due to their unique magnetically responsive properties and high biocompatibility. This review focuses on assessing the potential applications of MNPs in enhancing tumor accumulation of immunotherapeutic agents and immunogenicity, improving immune cell infiltration, and creating an immunotherapy-sensitive environment. We summarize recent progress in the application of MNP-based manipulators to augment the efficacy of immunotherapy, by MNPs and their multiple magnetically responsive effects under different types of external magnetic field. Furthermore, we highlight the mechanisms underlying the promotion of antitumor immunity, including magnetically actuated delivery and controlled release of immunotherapeutic agents, tracking and visualization of immune response in real time, and magnetic regulation of innate/adaptive immune cells. Finally, we consider perspectives and challenges in MNP-based immunotherapy. [ABSTRACT FROM AUTHOR]

The poor physical property and strong heterogeneity of Triassic Yanchang formation in Huanjiang oilfield of Ordos Basin are the main reasons for uneven water absorption, partial injection wells underinjection at high pressure, and decline of production. Previously, large numbers of conventional acidifications were used for plugging removal in the reservoir, but the effect was not so good and effective period was short. Aiming at the geological characteristics of Huanjiang oilfield, an online shunt acidification and augmented injection technology which does not stop water injection, pull original production strings out, and continuously inject acid and diverting agent has been proposed. A chelating acid COA-1S with low corrosion rate (0.3675 g/(m2·h)), good retardation capacity (hydrolysis constant = 1.2 × 10−6), and effective chelating ability (precipitation inhibition rate >95%) has been developed, as well as a diverting agent COA-1P with good dispersion in acid solution, diversion effect, and particle size (10–100 μm), which behaves well in COA-1S acid. It has been proved that the online acid system has a good diversion acidizing ability and plugging removal performance in a deep area in the laboratory core physical simulation test. The field test results show that the online shunt acidizing and augmented injection technology could reduce the injection pressure significantly (4.2 MPa) and increase water injection by 10 m3/d for the measured well (H5) and improve the water injection profile prominently. The online shunting acidification and augmented injection technology have the following advantages: simple procedures, fewer equipment needed, high efficiency of depressurization, and increasing water injection, which could effectively improve the profile of water wells, and there is a bright future of the technology. [ABSTRACT FROM AUTHOR]

Hydrogels resulting from the self-assembly of small peptides are smart nanobiomaterials as their nanostructuring can be readily tuned by environmental stimuli such as pH, ionic strength and temperature, thereby favoring their practical applications. This work reports experimental observations of formation of peptide hydrogels in response to the redox environment. Ac-IK-NH is a short peptide amphiphile that readily self-assembles into long nanofibers and its gel formation occurs at concentrations of about 10 mmol/L. Introduction of a Cys residue into the hydrophilic region leads to a new molecule, Ac-ICGK-NH, that enables the formation of disulfide bonds between self-assembled nanofibers, thus favoring cross-linking and promoting hydrogel formation. Under oxidative environment, Ac-ICGK-NH formed hydrogels at much lower concentrations (even at 0.5 mmol/L). Furthermore, the strength of the hydrogels could be easily tuned by switching between oxidative and reductive conditions and time. However, AFM, TEM, and CD measurements revealed little morphological and structural changes at molecular and nano dimensions, showing no apparent influence arising from the disulfide bond formation. [ABSTRACT FROM AUTHOR]

Abstract: The oil–water separation and dispersed phase droplet or flocculate droplet or flocculate size variation in the heavy oil emulsion were analyzed by using the Turbiscan Lab stability analyzer. The demulsification process of the heavy oil emulsion was described as well. The results indicated that three-phase separation took place slowly in the heavy oil emulsion and the emulsion middle layer finally formed between the oil phase and water phase, and the demulsification was mainly caused by the dispersed phase droplets sedimentation. After the chemical demulsifier was added into the emulsion, two-phase separation took place quickly, the emulsion stability data accurately conformed to the emulsion stability model based on the two-phase separation. Comparing the characteristic of the demulsification process of the heavy oil emulsion before and after the addition of demulsifier, it indicated that the coalescence of the dispersed phase droplets is the controlling factor and crucial step of the demulsification. [Copyright &y& Elsevier]

Effective delivery of anticancer drugs into the nucleus for pharmacological action is impeded by a series of intratumoral transport barriers. Despite the significant potential of magnetic nanovehicles in electromagnetic field (EF)‐activated drug delivery, modularizing a tandem magnetoresponsive activity in a one‐nanoparticle system to meet different requirements at both tissue and cellular levels remain highly challenging. Herein, a strategy is described by employing sequential EF frequencies in inducing a succession of magnetoresponses in the magnetic nanovehicles that aims to realize cascaded tissue penetration and nuclear accumulation. This nanovehicle features ferrimagnetic vortex‐domain iron oxide nanorings coated with a thermo‐responsive polyethylenimine copolymer (PI/FVIOs). It is shown that the programmed cascading of low frequency (Lf)‐EF‐induced magnetophoresis and medium frequency (Mf)‐EF‐stimulated magneto‐thermia can steer the Doxorubicin (DOX)‐PI/FVIOs to the deep tissue and subsequently trigger intracellular burst release of DOX for successful nuclear entry. By programming the order of different EF frequencies, it is demonstrated that first‐stage Lf‐EF and subsequent Mf‐EF operation enables DOX‐PI/FVIOs to effectively deliver 86.2% drug into the nucleus in vivo. This nanodelivery system empowers potent antitumoral activity in various models of intractable tumors, including DOX‐resistant MCF‐7 breast cancer cells, triple‐negative MDA‐MB‐231 breast cancer cells, and BxPC‐3 pancreatic cancer cells with poor permeability. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS), a group of oxygen derived radicals and derivatives, can induce cancer cell death via elevated oxidative stress. A spatiotemporal approach with safe and deep‐tissue penetration capabilities to elevate the intracellular ROS level is highly desirable for precise cancer treatment. Here, a mechanical‐thermal induction therapy (MTIT) strategy is developed for a programmable increase of ROS levels in cancer cells via assembly of magnetic nanocubes integrated with alternating magnetic fields. The magneto‐based mechanical and thermal stimuli can disrupt the lysosomes, which sequentially induce the dysfunction of mitochondria. Importantly, intracellular ROS concentrations are responsive to the magneto‐triggers and play a key role for synergistic cancer treatment. In vivo experiments reveal the effectiveness of MTIT for efficient eradication of glioma and breast cancer. By remote control of the force and heat using magnetic nanocubes, MTIT is a promising physical approach to trigger the biochemical responses for precise cancer treatment. [ABSTRACT FROM AUTHOR]

The rheological properties of a pH-sensitive clean fracturing fluid system formed by the anionic surfactant N -hexadecyl iminodiacetic acid (HIA), which has two carboxyl groups, and salt-free cationic hexadecyl trimethyl ammonium bromide (CTAB) have been carefully studied. Viscoelastic wormlike micelles (WLMs) were prepared in a HIA/CTAB hybrid system. The increased electrostatic interactions between the heads of HIA and CTAB lead to a structural transition from spheres to WLMs as a function of pH. Large-scale coarse-grained molecular dynamics (CGMD) revealed that the formation of WLMs can be described in three stages: "oligomer-to-sphere" fusion; "sphere-to-rod" fusion; and "'rod-to-rod" fusion. The simulation results show that electrostatic repulsion occurs among the carboxyl groups of HIA and that HIA is screened by the positively charged heads of CTAB, which leads to an increase in solution viscosity. The excellent rheological properties and pH sensitivity of the clean fracturing fluid significantly improve the seaming capacity and reservoir protection of the fracturing fluid, thus helping to increase the productivity of the well after fracturing and control the construction cost. [ABSTRACT FROM AUTHOR]

Abstract A novel CO 2 responsive anionic smart wormlike micelles (SWLMs) was constructed by simply mixing sodium oleate (NaOA) and the small organic counterion 2, 6, 10-trimethyl-2, 6, 10-triazaundecane (TMTAD) in a 3:1 M ratio without complex organic synthesis. After bubbling CO 2 , TMTAD and NaOA molecules in aqueous solution, a pseudo Gemini surfactant is formed in situ due to electrostatic interactions. This system shows two obvious performance transitions when CO 2 is continuously introduced, from a water-like solution to a viscoelastic fluid and then a milky solution. Such transitions reflect the continuous transformation of the self-assembled structure from spherical micelles to wormlike micelles and then vesicle or spherical micelles. Additionally, this system can exhibit two similar sequential transformations when the pH changes in the reverse process. Highlights • A novel CO 2 -controllable smart nanostructured fluids in a pseudo Gemini surfactant system is constructed. • Characteristics of SWLMs are systematically analyzed. • Reversible transition mechanisms of SWLMs induced by CO 2 are proposed. [ABSTRACT FROM AUTHOR]

Evaluating enzyme activity intracellularly on natural substrates is a significant experimental challenge in biomedical research. We report a label‐free method for real‐time monitoring of the catalytic behavior of class A, B, and D carbapenemases in live bacteria based on measurement of heat changes. By this means, novel biphasic kinetics for class D OXA‐48 with imipenem as substrate is revealed, providing a new approach to detect OXA‐48‐like producers. This in‐cell calorimetry approach offers major advantages in the rapid screening (10 min) of carbapenemase‐producing Enterobacteriaceae from 142 clinical bacterial isolates, with superior sensitivity (97 %) and excellent specificity (100 %) compared to conventional methods. As a general, label‐free method for the study of living cells, this protocol has potential for application to a wider range and variety of cellular components and physiological processes. Heat of the moment: A label‐free method for real‐time monitoring of carbapenemase activity in live bacteria is based on measurement of heat changes induced by hydrolysis of the substrate imipenem. This in‐cell calorimetry approach offers major advantages in rapid screening of carbapenemase‐producing Enterobacteriaceae in clinical bacterial isolates, with superior sensitivity and excellent specificity compared to conventional methods. [ABSTRACT FROM AUTHOR]

Evaluating enzyme activity intracellularly on natural substrates is a significant experimental challenge in biomedical research. We report a label‐free method for real‐time monitoring of the catalytic behavior of class A, B, and D carbapenemases in live bacteria based on measurement of heat changes. By this means, novel biphasic kinetics for class D OXA‐48 with imipenem as substrate is revealed, providing a new approach to detect OXA‐48‐like producers. This in‐cell calorimetry approach offers major advantages in the rapid screening (10 min) of carbapenemase‐producing Enterobacteriaceae from 142 clinical bacterial isolates, with superior sensitivity (97 %) and excellent specificity (100 %) compared to conventional methods. As a general, label‐free method for the study of living cells, this protocol has potential for application to a wider range and variety of cellular components and physiological processes. [ABSTRACT FROM AUTHOR]

Functional nanoparticles possess great potential for precise diagnosis and optimum therapy of serious diseases. However, their application is limited by structural heterogeneity and physical properties, low drug-loading efficiency, the absence of effective drug release, and some undetermined physiological and biochemical properties. Effective surface modification is able to overcome these limitations and largely improve the application performance of functional nanoparticles in biomedicine. Nevertheless, chemical or physical surface modifications using conventional surfactants are difficult to ensure homogeneous construction and normal metabolism of nanoparticles in vivo . Recent progress in this field has demonstrated that nucleic acid-modified nanoparticles can attain efficient transport, steady state and rational metabolism, as well as clear targeting and controllable drug release. All of these advantages are attributed to the special steric structure, homology, and biological functions of nucleic acids. Moreover, abundant active sites on the nucleic acid skeleton not only facilitate the direct or indirect connection of nanoparticles, but also support retention of the functions of both nanoparticles themselves and nucleic acids. In this review, we summarize the outstanding respective characteristics and prospects of nucleic acid-modified nanoparticles. In addition, primary surface modification techniques for preparing nucleic acid-modified nanoparticles, including non-scaffold-mediated modification and scaffold-mediated modification, were highlighted. Furthermore, interactions between nanoparticles and nucleic acids, as well as the effects of modification techniques on the properties of nucleic acid modified nanoparticles, are discussed in detail. [ABSTRACT FROM AUTHOR]

Vinyl Benzoate/Heptadecafluorodecyl acrylate (VBe/HFDA) co-polymers were synthesized and characterized as thickening agents for supercritical carbon dioxide (SC-CO2). The solubility and thickening capability of the co-polymer samples in SC-CO2 were evaluated by measuring cloud point pressure and relative viscosity. The molecular dynamics (MD) simulation for all atoms was employed to simulate the microscopic molecular behavior and the intermolecular interaction of co-polymer-CO2 systems. We found that the introduction of VBe group decreased the polymer-CO2 interaction and increased the polymer-polymer interaction, leading to a reduction in solubility of the co-polymers in SC-CO2. However, the co-polymer could generate more effective inter-chain interaction and generate more viscosity enhancement compared to the Poly(Heptadecafluorodecyl) (PHFDA) homopolymer due to the driving force provided by π-π stacking of the VBe groups. The optimum molar ratio value for VBe in co-polymers for the viscosity enhancement of SC-CO2 was found to be 0.33 in this work. The P(HFDA0.67-co-VBe0.33) was able to enhance the viscosity of SC-CO2 by 438 times at 5 wt. %. Less VBe content would result in a lack of intermolecular interaction, although excessive VBe content would generate more intramolecular π-π stacking and less intermolecular π-π stacking. Both conditions reduce the thickening capability of the P(HFDA-co-VBe) co-polymer. This work presented the relationship between structure and performance of the co-polymers in SC-CO2 by combining experiment and molecular simulations. [ABSTRACT FROM AUTHOR]

Enhancement of Fe3O4/Au nanoparticles ( Fe3O4/Au NPs) catalyst was observed in the oxidative degradation of methyl orange by employing H2O2 as oxidant. To evaluate the catalytic activity of Fe3O4/Au nanoparticles, different degradation conditions were investigated such as the amounts of catalyst, H2O2 concentration and pH value. Based on our data, methyl orange was degraded completely in a short time. The enhanced catalytic activity and increased oxidation rate constant may be ascribed to synergistic catalyst-activated decomposition of H2O2 to • OH radical, which was one of the strong oxidizing species. Besides, Fe3O4/Au nanoparticles have exhibited satisfying recycle performance for potential industrial application. [ABSTRACT FROM AUTHOR]

The thickening behavior and synergistic mechanism of the mixed system of the hydrophobically associating polymer (HAP-S) (acrylamide/acrylate-EOm-POn/sodium acrylate terpolymer) with small molecular weight and the acrylamide/N-isooctyl acrylamide/sodium acrylate terpolymer (HAP-L) with large molecular weight were investigated via the rheology, inclusion action of β-cyclodextrin (β-CD), cohesive energy, dynamic light scattering (DLS), and scanning electron microscope (SEM). The apparent viscosity of the mixed-system solution was higher than that of the HAP solution alone in a wide range of mass ratios and concentrations of the two polymers, ascribing to the enhancement of associated viscosity and strength of the network structure by forming mixed aggregates and bridging among them. Furthermore, the hydrodynamic radius of the mixed-system aggregates increased due to the improved network structure and the electrostatic repulsion effect among the different kinds of HAP molecules. Under the synthetical influence of the above-mentioned factors, the mixed system displayed better temperature resistance and salt tolerance as compared to the HAP solution alone. [ABSTRACT FROM AUTHOR]

High quality porous ZnO nanoplates with a pure crystal phase of hexagonal wurtzite structure were fabricated by thermal decomposition route for the first time. Electron microscopy investigations show that each porous ZnO nanoplates has a single-crystalline nature, which is self-assembled by tiny nanocrystals. The size and pore density of the ZnO nanoplates can be tuned by only changing the amount of zinc source. Magnetic investigations show that the magnetic phase can be converted from paramagnetism to ferromagnetism at room temperature, by increasing the pore density of ZnO nanoplates. The ZnO nanoplates with highest pore density show a d° room-temperature ferromagnetic characteristic, and the saturation magnetization reaches 26 memu/g. Several experimental evidences, including XPS, PL and ESR spectra, demonstrate that the defects of singly charged oxygen vacancies related to the pore density contribute to the long-range ferromagnetic ordering in the dopant-free porous ZnO nanoplates. This finding suggests that the pore-dependent ferromagnetism can be manipulated by tuning the surface-volume ratio, which is significant for the understanding and exploration of diluted magnetic semiconductors. [ABSTRACT FROM AUTHOR]

Although extensive work has been reported that micelles can induce depletion attraction between two solid spheres or a sphere and a plate, the effect of different micelles on the depletion between two soft surfaces has been rarely reported. Optical tweezers were used to measure the forces between two oil-in-water emulsions in solutions of sodium dodecylbenzenesulfonate (SDBS), cetyltrimethylammonium bromide (CTAB), and octylphenol polyoxyethylene ether with ten oxyethylene glycol ether (OP-10) at varying concentrations. When the concentration of surfactant below their critical micelle concentration (cmc), force profiles between two emulsion droplets were purely repulsive. As the concentration of SDBS or CTAB above its cmc, the attraction between like-charged O/W emulsion droplets was dominant. The coalescence of the like-charged O/W emulsion droplets is observed. For nonionic surfactants OP-10, even if the cmc had been reached, the attractive force between O/W emulsion droplets couldn't be measured. Results shows that attractive forces between two like-charged emulsion droplets of several microns in solution can also be induced by ionic micelles and the depletion was enhanced by counterion osmotic pressure. Our work suggests that the effect of micelle-induced depletion on the force between two solid surfaces can be used to predict forces between several micrometers of emulsion droplets. [Display omitted] [ABSTRACT FROM AUTHOR]

Polyacrylamide microspheres have recently drawn great attention in conformance control due to their advantages over traditional gel treatments. One important question that has been raised is whether the tiny particles can be produced from production wells. However, current products are difficult to use for detecting fluids generated by production wells. In this paper, the fluorescent polyacrylamide microspheres were successfully synthesized; they can emit blue fluorescence under ultraviolet irradiation. Their swelling property, fluorescence characteristics, rheology property, creep-recovery property, and plugging performance were evaluated in the laboratory. The results indicated that the microspheres could emit blue fluorescence under ultraviolet irradiation after passing through a fracture model. Their creep-recovery ability after deformation was very high, and their elastic recovery rate extended to 94.1%, which suggests that the microspheres almost recover to their original shape and size after deformation. The transparent fracture model plugging test shows that the microspheres can migrate and plug a fracture with a width of 0.3 mm, which is much smaller than the diameter of the microspheres. [ABSTRACT FROM PUBLISHER]

A ternary composite, Co 3 O 4 nanoparticles/N-doped graphene (NG)/carbon nanotubes (CNTs), has been synthesized by a simple hydrothermal method. N-doped graphene nanosheets were used as the substrate with excellent conductivity and a well conductive network is established through introducing CNTs. Due to the synergetic effects of Co 3 O 4 nanoparticles, N-doped graphene and embedded carbon nanotubes, the Co 3 O 4 /NG/CNTs electrode exhibits enhanced electrochemical performance than those of Co 3 O 4 /NG, Co 3 O 4 /graphene, which have a high specific capacitance of 456 F/g at a current density of 1 A/g. Additionally, a capacitance increase of 23.2% of the initial capacitance is observed after 1000 cycles at a current density of 1 A/g. The results provide a general strategy to design and prepare innovative ternary composites with 0-dimensional, 1-dimensional and 2-dimensional complex structures for diverse structure-sensitive applications. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) technology has been investigated for long time because of its tremendous potential in chemical and biomolecular detection. One of the challenging works in this field is to fabricate fantastic substrates with high sensitivity, stability, and reproducibility. This work reports a novel SERS substrate based on MnO 2 /Au hybrid nanowall film prepared by simple and cheap hydrothermal method combined with subsequent vacuum thermal evaporation process. Enhanced SERS enhancement factor (EF) with increased thickness of gold layer was observed and a significant increase of EF up to 8 orders of magnitude has been achieved. Finite-difference time-domain (FDTD) simulations have been carried out to elucidate the origin of the enhancement and the distribution of the “hot spots”. Experimental evidences indicate that the as-prepared substrate possesses excellent SERS sensitivity, good stability and high reproducibility. Our results provide a novel MnO 2 /Au hybrid nanowall film as a convenient and robust SERS-active substrate for detecting biomolecules. [ABSTRACT FROM AUTHOR]

An amphiphilic polymer in water could form an aggregate due to its hydrophobic groups. The rheological properties of the three amphiphilic polymers' solutions are different because of their different hydrophobic groups. By using a rheometer and a rotatory viscometer, the rheological properties and apparent viscosities of three kinds of amphiphilic polymers have been studied. The results show that all of the polymers are Newtonian fluids at a low shearing rate and pseudoplastic fluids at a high shearing rate. In addition, the amphiphilic polymer-P(AM/BHAM/NaA) has the best thickening behavior and the lowest value of critical aggregation concentration (CAC), which was also verified by fluorescence spectroscopy. By combining creep-recovery with cohesive energy calculation, the structural performance and interaction energy of the aggregate is the reason for the above mentioned phenomenon. By increasing the strength of hydrophobic groups, i.e., with an oil-water partition coefficient, then the structural viscoelasticity of the groups could be improved, and the associate is easily formed in the solution. [ABSTRACT FROM AUTHOR]

Improving the interaction of graphene with terahertz (THz) waves in experiment - through experimental measurement is a challenge for THz detectors, modulators, and other THz photonic components based on graphene. Hybridization of graphene with metamaterials leads to a strong THz response enhancement. Here, we observed maximum enhancement of 33.0% in non-resonant region and 23.8% in resonant region with the hybridization of graphene and metamaterials in experiment. A coupling model as well as numerical calculation has been carried out to fully investigate the influence of this coupling. The results suggest that there exists an exponential relationship between coupling strength and THz response in both resonant and non-resonant region, while the resonant frequency shift shows a linear growth with coupling strength. The bandwidth of the resonance shows exponential increasing with the damping constant. Correspondingly, the numerical calculation shows the similar dependency with the electrical conductivity of the graphene overlayer. This suggests a higher conductivity for stronger coupling. Substrates could also bring the remote phonon scattering, charge transfer, and dielectric effect, which show the influence such as low dielectric constant for high coupling. [ABSTRACT FROM AUTHOR]

The different polymer networks were constructed by two kinds of associations, one is host-guest inclusion between P(AM/A-β-CD/NaA) and P(AM/BHAM/NaA), and the other is hydrophobic association of P(AM/BHAM/NaA). Under the high-speed shearing, the viscosity survival and recovery rate of different systems were investigated. The results show the inclusion complex (CD:BHAM = 2:1) has excellent shearing resistance performance, and it was also verified by dynamic light scattering (DLS). This is mainly because the strength of inclusive association is stronger than that of hydrophobic one. The conclusion was proved by time-temperature superposition as well. It shows that the activation energy E of the inclusion complex (CD:BHAM = 2:1), which represents the strength of association, has a maximum value, while the activation energy E of P(AM/BHAM/NaA) has also a maximum one because of the multiple associative sites of hydrophobic associations. The activation energy values of the inclusion complex (CD:BHAM = 1:1) are intermediate since there are two kinds of associations in this solution. This is exactly the reason that the complex (CD:BHAM = 1:1) has the best emulsifying property. Moreover, the conclusions related to emulsifying property have been verified by using a laser particle size analyzer and Turbiscan lab stability. [ABSTRACT FROM AUTHOR]

The host cyclodextrin polymer-P(AM/A-β-CD/NaA) is prepared by redox free-radical copolymerization. Additionally, the multi-sticker amphiphilic polymer-P(AM/BHAM/NaA) as a guest polymer is synthesized using micellar polymerization. The copolymer structures are characterized by H NMR. Subsequently, all the polymers and inclusion complexes are evaluated in terms of apparent viscosity, optical absorption spectra and rheological property. The results indicate that the inclusion association between the cyclodextrin group (CD) and multi-sticker hydrophobic monomer (BHAM) is in accordance with ternary interaction (CD/BHAM = 2:1). Because of the inclusion association between the host and guest polymers, the solution of inclusion complex has much higher viscoelasticity even under the low amphiphilic polymer concentration. When the molar ratio of CD to BHAM is 1:1, the critical aggregation concentration (CAC) of the inclusion complex solution still remains. Furthermore, above the CAC, two types of associations, inclusion association and inter-molecular hydrophobic association, can occur in the complex solution and these interactions were also verified by fluorescence spectroscopy and atomic force microscopy (AFM). In this paper, the inclusion rule of cyclodextrin polymer with the multi-sticker amphiphilic polymer is discussed, and the rule of the enhanced solution viscosity is further explored. [ABSTRACT FROM AUTHOR]

Highlights: [•] Single-crystal α-Fe2O3 hollow structures are synthesized by hydrothermal method. [•] As-prepared α-Fe2O3 NRs and NTs are reduced at various temperatures by 5% H2/95% Ar. [•] We investigate the influence of reduction condition to the structure of products. [•] We investigate the influence of reduction condition to magnetic property of products. [•] The M s increases with increasing reduction temperature. [Copyright &y& Elsevier]

• The thermal-thickening polymer is synthesis by "graft onto" method. • The thickening properties can be designed on demand. • The mechanism of thickening properties is illustrated. The "graft onto" method is used to obtain the "stimuli-responsive water-soluble polymer" with low concentration, where 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and n-hydroxysulfosuccinimide sodium salt as catalyst and sodium polyacrylate as backbone chain. The molecular structure of the polymer is characterized by Nuclear Magnetic Resonance (1H NMR). The influence of temperature on polymer rheological properties and aggregation is studied by rheometer and fluorescence probe respectively. The results show that when the polymer concentration is higher than 1500 mg/L, the thickening properties can be controlled by diacetoneacrylamide, thermal-responsive monomer, NaCl and polymer concentration, where the apparent viscosity max / viscosity min (η max /η min) changes from 18.3 to 39.4, from 2.6 to 45.5, from 9.3 to 36, from 7.8 to 36.9 respectively and the lower critical solution temperature (LCST) changes from 60 °C to 40 °C. The reason for the polymer with controllable thickening properties is that the thermal-responsive monomers change from hydrophilicity to hydrophobicity, thus forming aggregations. At this time, the polymer chains form network structures. Because of controllable thickening properties at low concentration, it has potential application prospects. [ABSTRACT FROM AUTHOR]

Polymer microspheres have high swelling ratio, which can be used to improve the heterogeneity of low permeability reservoirs. When combined with a spontaneous emulsifying flooding system, the sweep efficiency of the system can be increased. However, due to its strong hydrophilicity, the conventional polymer microspheres cannot be adsorbed on the oil-water interface and reduce the interfacial tension, so as to improve the stability of emulsion and further improve the oil washing efficiency of spontaneous emulsion flooding. In this paper, surface-active microspheres S-PM are developed by using stearyl methacrylate (SMA) as the surface-active monomer. Compared with conventional polymer microspheres, the microspheres are amphiphilic particles with a swelling particle size of 600 nm, which can improve the stability of emulsions while improving the heterogeneity of low permeability reservoirs. The study of interfacial behavior shows that S-PM can decrease the interfacial tension to 0.005 mN/m by dragging surfactant molecules to the oil-water interface through polar action and increasing the surfactant concentration on the interface, and can increase the interfacial dilatational elastic modulus to 26.5 mN/m by forming a rigid adsorption layer. The emulsion stability analysis and micrographs show that S-PM can be distributed on the surface of the droplet. Due to the decrease of oil-water interfacial tension and the increase of interfacial strength, it is not easy to collide and coalesce, thus improving the emulsion stability. The dewatering rate decreases from 81.6% to 65.4%, and the TSI decreases from 9.7 to 5.3. The profile control results show that after adding S-PM, the spontaneous emulsifying flooding system is suitable for heterogeneous low-permeability reservoirs with permeability ratio below 5. This study expands the function of polymer microspheres, and it is expected to further improve the recovery of low permeability reservoirs by combining surface-active microspheres with a spontaneous emulsion flooding system. • Surface-active microspheres with interfacial adsorption property are proposed. • The mechanism of surface-active microspheres to stabilize emulsion is analyzed. • The profile control by surface-active microspheres to low permeability reservoir is evaluated. • Surface-active microspheres can both improve sweep coefficient and oil washing efficiency. [ABSTRACT FROM AUTHOR]

• A series of sulfate Gemini surfactants were synthesized and verified. • The molecular structure has influence on the surface and thermodynamic properties. • B-1–6 has the most excellent foaming ability and foam stability. In this article, a series of sulfate Gemini surfactants with different lengths of hydrophobic tail chains and spacer groups were synthesized. Both 1H NMR spectra and mass spectrometry analysis verified that the synthesized products were sulfate Gemini surfactants. Krafft temperatures indicated that they showed better water solubility at low temperatures. The conductivity of the sulfate Gemini surfactant versus concentration under different temperature conditions was tested. The influence of the hydrophobic tail chain, spacer group, and temperature on the critical micelle concentration and micelle thermodynamic parameters were revealed. The structure–activity relationship between the molecular structure and the foaming performance was discussed. Finally, we studied the influence of temperature on the foaming performance, foam stabilization, and rheological properties of the foam system. The insights gained from this study may enrich theoretical research on sulfate Gemini surfactants and promote the applications of sulfate Gemini surfactants in various fields. [ABSTRACT FROM AUTHOR]

The adsorption of anionic surfactant sodium dodecylbenzenesulfonate (SDBS) onto preformed particle gels (PPGs) and the effect of SDBS on the swelling ratio and rheology of PPGs were investigated. SDBS molecules can adsorb onto PPGs because of the hydrophobic association with the chain of PPGs at low concentration and the association of the SDBS micelles with the chains of PPGs at high concentration. PPGs contract and the shear stress of PPGs decreases after adsorption of SDBS. In addition, the storage modulus decreases first and then increases with increasing SDBS concentration. [ABSTRACT FROM PUBLISHER]