Electrical Conductivity Measurements Research Articles

Effect of La, Zr Doping on the Structural and Electrical Conduction Behaviour of BiFeO<sub>3</sub>-BaTiO<sub>3</sub> Ceramics

<p>This study presents a comprehensive investigation of the crystal structure and DC conduction mechanism of [(Ba<sub>0.7-x</sub> La<sub>x</sub>) Bi<sub>0.3</sub>][(Ti<sub>0.5</sub> Zr<sub>0.2</sub>) Fe<sub>0.3</sub>]O<sub>3</sub> with x = 0.00, 0.01, 0.03, 0.05 employing X-ray diffraction (XRD) and electrical conductivity measurements. Various compositions were synthesized through the solid-state ceramic route. XRD was used to investigate phase formation. Analysis of XRD data suggested a structural transition from cubic to tetragonal for x ≥ 0.01. The average crystallite size first increases for x = 0.01 and then decreases for x ≥ 0.03. The temperature-dependent electrical conductivity measurements were investigated over a wide temperature range which revealed distinct conductivity mechanisms governing the material's transport properties. The activation energy (E<sub>a</sub>) has been estimated from temperature-dependent DC conductivity. Overall, this study provides valuable insights into the correlation between crystal structure and electrical properties in [(Ba<sub>0.7-x</sub> La<sub>x</sub>) Bi<sub>0.3</sub>][(Ti<sub>0.5</sub> Zr<sub>0.2</sub>) Fe<sub>0.3</sub>]O<sub>3</sub>, offering significant implications for its potential applications in electronic and optoelectronic devices requiring tailored conductivity characteristics.</p>

Ion Conducting Polyethylene Oxide‐Based Polymer Electrolyte Dopped with Ionic Liquid‐Trifluoromethanesulfonic Chloride

AbstractIn last few decades, polymer electrolyte is the most promising candidate for the fabrication of electrochemical devices. In current work, the influence of adding the room‐temperature ionic liquid (trifluoromethanesulfonic chloride – CClF3O2S) in polyethylene oxide (PEO): ammonium iodide (NH4I) polymer electrolyte has been studied. The IL‐doped polymer electrolyte films are synthesized by solution casting method with varying stoichiometric ratios. Several experimental techniques including optical polarizing microscope, impedance spectroscopy, X‐ray diffraction, Linear sweep voltammetry, Ionic transference number thermal analysis, and electrical conductivity measurements at room temperature have been studied in detail. The complex material's maximum conductivity has been determined to be 3.3 × 10−5 S cm−1 at room temperature. The POM images show the increase in amorphous region which further confirm the improvement in ionic conductivity. Ionic transference number 0.96 shows the system is purely ionic in nature. The ESW of the IL doped polymer electrolyte is also sawed to be 3.32 V which is suitable for the fabrication of electrochemical devices.

Mapping charge excitations in generalized Wigner crystals.

Transition metal dichalcogenide-based moiré superlattices exhibit strong electron-electron correlations, thus giving rise to strongly correlated quantum phenomena such as generalized Wigner crystal states. Evidence of Wigner crystals in transition metal dichalcogenide moire superlattices has been widely reported from various optical spectroscopy and electrical conductivity measurements, while their microscopic nature has been limited to the basic lattice structure. Theoretical studies predict that unusual quasiparticle excitations across the correlated gap between upper and lower Hubbard bands can arise due to long-range Coulomb interactions in generalized Wigner crystal states. However, the microscopic proof of such quasiparticle excitations is challenging because of the low excitation energy of the Wigner crystal. Here we describe a scanning single-electron charging spectroscopy technique with nanometre spatial resolution and single-electron charge resolution that enables us to directly image electron and hole wavefunctions and to determine the thermodynamic gap of generalized Wigner crystal states in twisted WS2 moiré heterostructures. High-resolution scanning single-electron charging spectroscopy combines scanning tunnelling microscopy with a monolayer graphene sensing layer, thus enabling the generation of individual electron and hole quasiparticles in generalized Wigner crystals. We show that electron and hole quasiparticles have complementary wavefunction distributions and that thermodynamic gaps of ∼50 meV exist for the 1/3 and 2/3 generalized Wigner crystal states in twisted WS2.

Poly (vinyl alcohol) based carbon nanofibers as freestanding anodes for lithium‐ion batteries

AbstractIn this study, we investigated the iodination process for the preparation of water‐soluble polyvinyl alcohol (PVA)‐based carbon nanofibers (CNFs) and their electrochemical properties. Iodinated nanofibers were carbonized at different temperatures (600°C, 800°C) under an argon (Ar) atmosphere. Morphology and physical properties of fiber mats were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and thermogravimetric analysis (TGA), while electrical conductivity measurements were done using four probes. As a freestanding anode in half‐cell lithium batteries, the CNFs were prepared by electrospinning of PVA and PVA–CNT blend, which was exposed to iodine vapor at various temperatures (60, 80, and 100°C). Iodine vapor treatment at 80°C and subsequent carbonization at 800°C provided a 29% carbon yield. The resulting CNT‐containing optimized CNFs exhibited superior flexibility, electrical conductivity (2.16 S/cm), and handleability, making them a promising, binder‐free environmentally friendly carbon source for lithium‐ion batteries with high capacity (672 mAh/g at 50 mA/g). The study clearly showed that PVA might be an alternative precursor for the production of carbon micro‐ and nanofibers.Highlights Anodic performance of PVA‐based carbon nanofibers was analyzed. PVA precursor offers economic and environmental option for binder‐free electrodes. PVA–CNT composite nanofibers with optimized iodination and carbonization time identified as a promising high carbon yield carbon source for lithium‐ion batteries. CNT‐containing optimized carbon nanofibers exhibited superior flexibility and electrical conductivity (2.16 S/cm). Freestanding fiber anodes exhibited a higher capacity of 672 mAh/g, at 50 mA/g compared to conventional graphite anode (372 mAh/g).

PEGDA hydrogel microspheres with encapsulated salt for versatile control of protein crystallization

Due to their biocompatibility and adjustable chemical structure and morphology, hydrogels have great potential in many applications, and can be used to enhance protein crystal quality and crystallization efficiency, contributing to biomedicine manufacturing. Monodispersed PEGDA hydrogel microspheres (HMSs) were synthesized using a Lego-inspired microfluidic device. The generated droplets were then UV polymerized, partially hydrolyzed with 0.1 M NaOH solution to improve their absorption capacity, and soaked in a buffer solution containing 0, 0.5, 1, 2, and 4 M NaCl. Salt-loaded HMSs were used as the medium for the enhanced crystallization of hen egg white lysozyme from aqueous solutions. Different supersaturations were achieved in the protein solutions by releasing NaCl of different concentrations from HMSs, as confirmed by electrical conductivity measurements. HMSs with or without NaCl can both provide heterogeneous nucleation sites due to their nano-porous structure and wrinkled surface. The addition of NaCl-loaded HMSs to the protein solution can also increase or decrease the supersaturation in the whole solution or locally near the HMS, leading to controllable nucleation time and crystal size distribution dependent on the NaCl concentration loaded into HMSs.

Conductivity measurements in the 10–40 GHz band using Fabry–Pérot open resonator

In this paper we introduce a novel approach to measurement of electric conductivity of bulk, metallic samples. The method is based on a Fabry–Pérot Open Resonator operating in the plano-concave configuration. Because the resonator supports multiple TEM0,0,q modes, the proposed method provides properties of the sample-under-test at multiple frequencies in the band of 10 to 40 GHz with separation of ca. 1.5 GHz between consecutive frequency points. Contrary to other methods, it does not require that a sample is cut to any particular shape, as long as it is significantly larger than the TEM-mode beam waist and thicker that the penetration depth. It also provides high measurement accuracy that is comparable to alternative methods based on single-mode resonant setups and superior to the broadband transmission methods known in the literature. We demonstrate that the open resonator due to its relatively high Q-factor reaching 135000 can be successfully used in measurements of different samples of conductivity ranging from ca. 103 S/m (e.g. laminates based on carbon-fiber) up to the order of 107 S/m (e.g. aluminum alloys, copper). Using the measurement set-up we also demonstrate an interesting effect of strong frequency dependence of the effective conductivity of stainless steel. It is expected in all magnetic materials and results from large complex permeability of such samples. It is important to emphasize that no similar characterization campaigns are to be found in the literature.

COMPATIBILITY ANALYSIS OF THE SOIL CALCIUM CONTENT BY MULTIFREQUENCY EC SENSORS

Nowadays in precision agriculture, the on-the-go measurement of soil nutrients is an important research topic in the sustainable nutrient management practices. Determining the nutrient content of soils and the judicious and site-specific replacement of missing mineral compounds of soil has a major impact on production costs in terms of current fertilizer prices. Soil sensors currently on the market can only determine total soil salinity. Therefore, selective soil salinity testing is only possible using laboratory methods. However, these methods are rather expensive, slow, and cumbersome. Growers often need faster and cheaper soil sampling process and immediate results. We believe that by developing measurement models of soil sensors, the data delivery process could be significantly shortened, so that measurement results could be processed and used even in real time. In this paper, we prove that electrical conductivity measurements can be a suitable tool for the determination of the selective salinity of soil. In our experiments, the calcium cation content of soil was measured by conductometry in laboratory conditions. In our model, we investigated the effect of a reasonable and well-considered variation of the measuring current frequency on the measurement output variable, i.e. the electrical conductivity (often abbreviated as EC) value. Our experiments have shown that with multi-frequency, solutions containing predetermined concentrations of Ca2+ ions, the EC obtained as an output parameter follows different functions.

Hydroxyapatite nanoparticles reinforced polyvinyl alcohol/chitosan blend for optical and energy storage applications

AbstractBiopolymer blend nanocomposite films composed of polyvinyl alcohol (PVA) and chitosan (CS) with varying quantities of hydroxyapatite (HA) nanoparticles were developed using a green solution casting method. The formation of blend nanocomposite was confirmed by Fourier‐transform infrared spectroscopy (FTIR), ultraviolet–visible (UV) spectrometer, field‐emission scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Mechanical parameters such as tensile strength, percentage elongation at break, hardness, dielectric constant, and temperature‐dependent alternating current (AC) conductivity were analyzed. The bonding between the nanoparticles and PVA/CS blend was verified by the shift in distinctive peaks of blend in the nanocomposites to a higher wavenumber in the FTIR spectra. The UV spectra demonstrated the difference in absorbance and transmittance of the PVA/CS blend with the reinforcement of HA nanofillers. The bandgaps of the nanocomposites marginally decreased with an increase in nanoparticle loading. The SEM and XRD patterns revealed the ordered arrangement of the blend matrix due to the presence of nanoparticles. The assessment of thermal characteristics obtained from DSC and TGA demonstrated a clear increase in phase transition temperature and thermal stability of nanocomposites. The electrical conductivity measurement indicated a rise in dielectric constant and AC conductivity of blend nanocomposites with the addition of nanoparticles. The temperature‐dependent AC conductivity showed a reduction in activation energy as temperature and nanoparticle loading increased. The tensile strength and surface hardness of the PVA/CS blend nanocomposite increased with the dosage of HA content in the blend matrix.Highlights A series of polyvinyl alcohol (PVA)/chitosan (CS)/hydroxyapatite (HA) nanocomposites were prepared by the green method Enhanced optical property, thermal stability, and glass transition temperature Possess excellent dielectric constant and alternating current conductivity The inclusion of HA increased the mechanical strength of the PVA/CS blend A potential blend nanocomposite for flexible optoelectronic and charge storage devices.

Spatial and temporal variability of environmental proxies from the top 120 m of two ice cores in Dronning Maud Land (East Antarctica)

Abstract. The Antarctic ice sheet's future contribution to sea level rise is difficult to predict, mostly because of the uncertainty and variability of the surface mass balance (SMB). Ice cores are used to locally (kilometer scale) reconstruct SMB with a very good temporal resolution (up to sub-annual), especially in coastal areas where accumulation rates are high. The number of ice core records has been increasing in recent years, revealing an important spatial variability and different trends of SMB, highlighting the crucial need for greater spatial and temporal representativeness. We present records of density, water stable isotopes (δ18O, δD, and deuterium excess), major ions concentrations (Na+, K+, Mg2+, Ca2+, MSA, Cl−, SO42-, and NO3-), and continuous electrical conductivity measurement (ECM), as well as age models and resulting surface mass balance from the top 120 m of two ice cores (FK17 and TIR18) drilled on two adjacent ice rises located in coastal Dronning Maud Land and dating back to the end of the 18th century. Both environmental proxies and SMB show contrasting behaviors, suggesting strong spatial and temporal variability at the regional scale. In terms of precipitation proxies, both ice cores show a long-term decrease in deuterium excess (d-excess) and a long-term increase in δ18O, although less pronounced. In terms of chemical proxies, the non-sea-salt sulfate (nssSO42-) concentrations of FK17 are twice those of TIR18 and display an increasing trend on the long-term, whereas there is only a small increase after 1950 in TIR18. The SO42-/Na+ ratios show a similar contrast between FK17 and TIR18 and are consistently higher than the seawater ratio, indicating a dominant impact of the nssSO42- on the SO42- signature. The mean long-term SMB is similar for FK17 and TIR18 (0.57 ± 0.05 and 0.56 ± 0.05 mi.e.yr-1, respectively), but the annual records are very different: since the 1950s, TIR18 shows a continuous decrease while FK17 has shown an increasing trend until 1995 followed by a recent decrease. The datasets presented here offer numerous development possibilities for the interpretation of the different paleo-profiles and for addressing the mechanisms behind the spatial and temporal variability observed at the regional scale (tens of kilometers) in East Antarctica. The “Mass2Ant IceCores” datasets are available on Zenodo (https://doi.org/10.5281/zenodo.7848435; Wauthy et al., 2023).

Coupling Effect of Mn Addition and Deformation on Mechanical and Electrical Properties of Al-Zr Alloys

In order to increase the strength of Al-Zr alloys, which are promisingly used for heat-resistant conductors, the coupling effect of Mn addition (0.16 wt.% and 0.88 wt.%) and deformation on the precipitation, mechanical, and electrical properties of an Al-0.18wt.% Zr alloy was studied using transmission electron microscopy (TEM), atom probe tomography (APT), hardness testing, and electrical conductivity measurement, respectively. Results showed that the Mn addition fully suppresses the Al3Zr precipitation in both hot-deformed and undeformed cases, which is mainly due to a strong Mn-vacancy bonding, in which Mn atoms seize vacancies and hence reduce the available vacancies for Al3Zr nucleation. Minor 0.16 wt.% Mn addition causes a simultaneous decrease in hardness and electrical conductivity, regardless of whether there is deformation. The higher 0.88 wt.% Mn addition, however, significantly increases the hardness by over 40%, especially in combination with deformation. Possible influencing factors such as grain size, dislocations, intergranular/intragranular precipitation, and solute clusters are comparatively discussed in terms of microstructural features and mechanical/electrical properties that are tuned by Mn addition and/or deformation. It is found that the Mn addition can make remarkable contributions to the hardness and thermal stability of the Al-Zr alloys when coupled with deformation.

Complex electrical measurements of waste rock during acid mine drainage generation and release: Kinetic column tests

Acid mine drainage (AMD) emanating from waste rock piles (WRPs) at mining sites is a global concern. Successful rehabilitation of these sites requires effective characterization and monitoring of the waste rock during AMD generation/release. Traditional approaches involve ex-situ analysis of waste rock and porewater samples collected via corings and monitoring wells; however, this is highly disruptive, costly, and provides sparsely distributed point information across enormous volumes typical of WRPs. Geoelectrical techniques are a promising approach for non-invasive continuous imaging; however, their application has been limited to ‘one-off’ imaging with few studies on monitoring waste rock evolution. The objective of this study is to assess the geoelectrical signatures of changing waste rock during AMD generation/release. Field waste rock samples were extracted from three mine WRPs and first characterized for mineralogy and acid generation potential. Kinetic tests were then performed on each sample using leaching columns and humidity cells, with simultaneous measurements of effluent quality and complex electrical conductivity (real and imaginary components measure conduction and polarization, respectively). Results show that real conductivity was highly sensitive to changes associated with AMD leachate quality (e.g., 28,800 to 68 mg/L acidity) and surface of the waste material. Imaginary conductivity measurements identified changes in the waste mineralogy over time, though these signatures were not very distinct, which is likely due to low sulfide contents and limited oxidation (e.g., 0.59 wt% sulfide and 33% air saturation). This study improves our understanding of geoelectrical signatures associated with real waste rock, demonstrating the potential application of the electrical resistivity tomography and induced polarization techniques for mine waste investigations.

Molecular Signal Transfer of Highly Diluted Antibodies to Interferon-Gamma Regarding Kind, Time, and Distance of Exposition.

Physicochemical examinations of very high dilution (UHD) solutions subjected to certain physical factors (such as shaking) are becoming more frequent and are increasingly producing conclusive results. A much less studied phenomenon is the transfer of molecular information (i.e., UHD signals of dilute substances) from one liquid to another without an intermediate liquid phase. The aim of this study was to investigate the possibility of such a transfer of the UHD signal from the UHD solutions to the receiver solution, in particular, if the molecular source used in the donor solutions was the biologically active antibodies to interferon-gamma molecule. We were especially interested in how the transfer of the UHD signal is affected by the time of exposure of the receiver to the donor, the distance between the two, and how the transfer is affected by activation (striking) versus exposure alone. Signal transfer was evaluated by differential measurements of electrical conductivity, ORP, pH, and UV/VIS spectroscopy of the exposed liquid. The results showed that activation strongly influences signal transfer and that this can be compensated to some extent by prolonged direct exposure. In principle, exposure time has a positive effect on signal transfer. Interestingly, the results of different distances between the donor and receiver showed similar changes in the parameters in the range of 0-4 cm, as estimated in this study. While the study mainly confirms the two hypotheses, it also raises a number of new questions and provides clues for further research.

Unravelling the doping mechanism and origin of carrier limitation in Ti-doped In2O3 films

Ti-doped In2O3 thin films with varying Ti contents are prepared by partial reactive co-sputtering using ceramic In2O3 and metallic Ti targets and characterized by in situ x-ray photoelectron spectroscopy, electrical conductivity, and Hall-effect measurements. For a substrate temperature of 400°C, the carrier concentration increases faster than the Ti content and saturates at ≈7.4×1020cm−3. Based on these results, it is suggested that Ti does not directly act as donor in In2O3 but is rather forming TiO2 precipitates and that the related scavenging of oxygen generates oxygen vacancies in In2O3 as origin of doping. Neutralization of oxygen vacancies is, therefore, suggested to be origin of the limitation of the carrier concentration in Ti-doped In2O3 films.

Automated Drift Compensation System for Electrical Conductivity and pH Probes in Hydroponic Systems

Highlights Used one- and two-point normalization to compensate for drifts in EC and pH probes in hydroponic systems. Developed automated sensor drift compensation systems for hydroponic systems. Evaluated the compensation systems for open- and closed-hydroponics. Application of the normalization methods increased the accuracy of the EC and pH measurements. Abstract. In hydroponic systems, the nutrient solutions are dispensed based on pH and electrical conductivity (EC) to ensure that the nutrient components in the solution are optimal for crop growth. However, the pH and EC probes may exhibit signal drifts when immersed in the solution for a considerable period, which deteriorate the measurement accuracy and the nutrient and water use efficiency. Notably, the existing hydroponic systems require manual calibration of the pH and EC probes and do not provide any information regarding their accuracy. Consequently, faults in the probes are challenging to detect. In this study, two types of automated drift compensation systems for EC and pH probes, based on one- and two-point normalization, were developed to accurately monitor changes in the pH and EC values in hydroponic solutions and enhance sensor management. The proposed framework can provide information regarding the drifts of the pH and EC probes through automated normalization solution measurements. The effectiveness of the developed system in scenarios involving plant growth with open and closed hydroponics was evaluated through comparison with a standard method involving sampling and laboratory analysis. The results indicated that the one-point normalization strategy had a simple structure and was effective in compensating drifted offsets of sensors. A two-point normalization strategy could effectively predict the sensor drifts as well as variations in the sensitivities, which could be used in the compensation processes. Application of the one-point normalization-based system increased the accuracy of the EC and pH measurements, with root mean square errors decreasing from 50 to 28.5 µS·cm-1 and 0.43 to 0.17 pH in the open hydroponic systems and from 68.7 to 38.3 µS·cm-1 and 0.15 to 0.11 pH in the closed systems, respectively. The two-point normalization-based system decreased the RMSEs from 44.6 to 33.4 µS·cm-1 and 0.55 to 0.20 pH for the EC and pH measurements, respectively. In addition, the decreased slope and coefficient of determination in the linear regression according to the system application proved the system can compensate for the drifts of the EC and pH probes. The proposed system provided accurate EC and pH measurements and sensor status information, promoting more efficient nutrient use and sensor maintenance. Keywords: Automation, Compensation, Drift, EC, Hydroponics, pH.

Effect of indomethacin on the electrical conductance and electrochemical voltammetry of copper chloride in methanol, ethanol, and their binary mixture with water

This study investigated the physicochemical properties of the interaction of indomethacin and copper chloride using the electrical conductance measurement in methanol, ethanol, and their binary mixture with water at room temperature (298.15 K), to determine the solvation behavior, redox behavior, and kinetics. The association parameters were computed using the Fuoss-Hsia-Fernández-Prini and Fuoss-Shedlovsky models. The standard Gibbs energy for association (ΔGoA), Walden product (Λoηo), and hydrodynamic radii (RH) were calculated to study the interaction of indomethacin and copper chloride. On the other hand, cyclic voltammetry examines the electrochemical redox behavior of copper chloride using a gold electrode and its interactions with indomethacin. Results showed changes in peak potentials and currents density in the presence of indomethacin, indicating alterations in redox behavior and reaction rates. Overall, this research can be valuable in understanding the electrochemical properties and potential applications of indomethacin and copper chloride, as well as in developing new drugs or therapeutic agents, which could have has implications in various fields, including drug development, electrochemistry, and materials science.

Use of milk’s electrical conductivity in the detection of mastitis

Mastitis is a costly udder disease affecting dairy cattle. Decreased milk yield, treatment and labor costs, decreased milk quality and cow death etc. are some of the factors that make up costs. These losses are caused by subclinical mastitis without visible symptoms. Mastitis can be detected by performing one of the simple screening tests such as electrical conductivity (EC) measurement of milk. Our study evaluated the use of this method for the detection of subclinical and clinical mastitis.

Thermal annealing effects on the structural and electrical properties of Ag2La thin films deposited by thermal evaporation technique

Herein Ag2La thin films are fabricated by a vacuum coating method and subjected to a thermal annealing process. The thermally heated of films at 200 o C increased the crystallite sizes and improved the crystalline structure of the films. For these films the electrical conductivity measurements which were handled in the temperature range of 300- 440 K. The conductivity analyses indicated that the transport of charged particles is dominated by the thermionic emission and by the variable range hopping conduction mechanisms. The annealing of films shifted the impurity levels and decreased; the degree of disorder, the average hopping distance and the average hopping energy.

Synthesis, Characterization and Antimicrobial Study of Some Transition Metal Complexes with Aldimine

Abstract: Aldimine ligand 2-Hydroxy-4,5- diiodo-benzylidene-4-hydroxy-aniline (L) and its complexes with Cu (II), Ni (II), Co (II) and Zn (II) were prepared and characterized by analytical, spectroscopic (IR, UV-Vis) techniques, thermal study, electrical conductivity and magnetic measurements. The results indicate that the ligand coordinate through azomithine nitrogen and oxygen of enolic group. The complexes were further screened for antimicrobial activity.

Sustainable Utilization of Surfactant-Free Microemulsion Regulated by CO2 for Treating Oily Wastes: A Interpretation of the Response Mechanism.

Surfactant-free microemulsions (SFMEs) have been explored extensively to avoid the residual surfactant problem caused by traditional surfactant microemulsions. Many researchers focused on the SFMEs with tertiary amine, which exhibited the typical CO2 response behavior. In this study, the phase diagram of the SFMEs consisting of tripropylamine (TPA), ethanol, and water was readily prepared via the measurements of electrical conductivity. The CO2 response behavior of SFME was confirmed by determination of conductivity and measurement of the average diameter of SFME, which was mainly dependent on the protonation of TPA induced by the additional CO2. The transition of protonated TPA to a more hydrophilic nature from lipophilicity to hydrophilicity should be responsible for the variation of SFME average diameter. In addition, the SFMEs exhibited remarkable solubilizing capacity of crude oil, and three types of SFMEs achieved more than 80% oil removal rate in the washing process of oil sands. It was noted that both oil-in-water and bicontinuous SFMEs could be circularly utilized at least three times with a relatively high oil removal rate (%). Our work provided the insight perspective on the mechanism of SFMEs with a CO2 response behavior.

Activation of Ostwald ripening and electrical conductivity in polyHIPEs through the addition of ascorbic acid to graphene-stabilized emulsions

Ascorbic acid was employed to increase the sphere-to-sphere contact of polyHIPEs. Adding a radical inhibitor to the aqueous phase of a graphene-stabilized water-in-oil emulsion was hypothesized to delay the formation of a polymer skin around the dispersed droplet, leading to intimate contact between the surfactant-stabilized drops. Optical microscopy analysis of samples made with varying ascorbic acid concentrations showed decreased sphere size and increased size dispersity at increasing inhibitor concentrations. Electrical conductivity measurements showed an increase at low concentrations of ascorbic acid but a decrease in conductivity at higher concentrations. Our results suggest that the presence of an inhibitor does delay the formation of the polymer skin and allows more intimate contact between spheres, but at higher concentrations, it leads to Ostwald ripening. Scanning electron microscopy of polystyrene/graphene composites revealed that the inhibitor also stopped the polymerization of aqueous-dispersed monomer, leading to polymer patches on the interior of the spheres.