Viscosity Enhancement Research Articles

Molecular Dynamics Simulation of the Viscosity Enhancement Mechanism of P-n Series Vinyl Acetate Polymer–CO2

Carbon dioxide (CO2) drive is one of the effective methods to develop old oil fields with high water content for tertiary oil recovery and to improve the recovery rate. However, due to the low viscosity of pure CO2, it is not conducive to expanding the wave volume of the mixed phase, which leads to difficulty utilizing the residual oil in vertical distribution and a low degree of recovery in the reservoir. By introducing viscosity enhancers, it is possible to reduce the two-phase fluidity ratio, expanding the degree of longitudinal rippling and oil recovery efficiency. It has been proven that the acetate scCO2 tackifier PVE can effectively tackify CO2 systems. However, little research has been reported on the microscopic viscosity enhancement mechanism of scCO2 viscosity enhancers. To investigate the influence of a vinyl acetate (VAc) functional unit on the viscosity enhancement effect of the CO2 system, PVE (Polymer–Viscosity–Enhance, P-3) was used as the parent, the proportion of VAc was changed, and the molecules P-1 and P-2 were designed to establish a molecular dynamics simulation model for the P-n-CO2 system. The molecules in the system under the conditions of 70 °C-10 MPa, 80 °C-10 MPa, and 70 °C-20 MPa were simulated; the viscosity of the system was calculated; and the error between the theoretical and simulated values of the viscosity in the CO2 system was relatively small. The difference between P-n molecular structure and system viscosity was analyzed at multiple scales through polymer molecular dynamics simulations and used the molecular radial distribution function, system density, accessible surface area, radius of gyration, minimum intermolecular distance, and minimum number of intermolecular contacts as indicators. This study aimed to elucidate the viscosity enhancement mechanism, and the results showed that the higher the proportion of VAc introduced into the molecules of P-n-scCO2 viscosities, the larger the molecular amplitude, the larger the effective contact area, and the greater the viscosity of the system. Improvement in the contact efficiency between the ester group on the P-n molecule and CO2 promotes the onset of solvation behavior. This study on the microscopic mechanism of scCO2 tackifiers provides a theoretical approach for the design of new CO2 tackifiers.

Harnessing nano-synergy: A comprehensive study of thermophysical characteristics of silver, beryllium oxide, and silicon carbide in hybrid nanofluid formulations

Nanofluids, promising to improve heat transfer efficiency, encounter stability and durability challenges, hindering their industrial applications. The emerging concept of hybrid nanofluids, alongside surfactant-driven stability research, presents a promising solution to tackle challenges in heat transfer, potentially revolutionizing thermal management systems and advancing nanomaterial science. This comprehensive study investigates the thermophysical properties of simple and hybrid nanofluid formulations composed of silver (Ag), beryllium oxide (BeO), and silicon carbide (SiC) nanoparticles dispersed in water. Hybrid nanofluids were prepared with varying volumetric ratios of 20:80, 40:60, 60:40, and 80:20 and examined across temperatures ranging from 15 to 45 °C. The influence of surfactants on stability was explored to augment thermal characteristics. Results revealed that the surfactants have a significant effect on stability and the specific mixing ratios can lead to more favourable thermal characteristics. Thermal conductivity enhancements, evaluated via the transient hot-wire method, demonstrated improvements of 7.43 %, 7.17 %, and 5.31 % for Ag/SiC (60:40), Ag/BeO (60:40), and SiC/BeO (80:20) hybrid nanofluids, respectively, compared to water. Viscosity measurements revealed Newtonian behaviour for the Ag, SiC, and BeO nanofluids, with a minimum viscosity enhancement of 3.01 % observed for the BeO nanofluid. Hybrid Ag/SiC nanofluid demonstrated a maximum viscosity enhancement of 4.90 % for 20:80 formulation. Density analysis showed maximum augmentation of 0.25 %, 0.097 %, and 0.0775 % for the Ag, SiC, and BeO nanofluids respectively at 0.025 vol% while hybrid Ag/SiC nanofluid exhibited a maximum of 0.23 % density increase for the 80:20 composition. The statistical models were also developed to predict properties against temperature. Furthermore, the cost analysis identified Ag nanofluid as the most expensive option, while the SiC/BeO hybrid was the most economical. However, the Ag-SiC (60:40) hybrid nanofluid offered a balanced trade-off between properties and cost.

An Investigation of the Factors Influencing the High Temperature Rheology of Polymers

Introduction: Nowadays, polymers, as an important application material in drilling engineering, have obvious advantages in solving the rock-carrying problem at the bottom of deep wells, and improving the drilling speed due to their excellent viscosity enhancement effect. Method: In this study, the effects of polymer type, concentration, shear time, electrolyte, and clay on the rheological properties of polymer solutions at high temperature and high pressure were investigated using a Fann 50SL rheometer. The experimental results showed that, except for the polymer additive amount and clay, the increase in shear time and the amount of salt both led to a decrease in the viscosity of the polymer solution, with 190°C as the critical temperature above which the viscosity decreased significantly. Results: The polymer solution containing formate showed higher viscosity retention during heating and then cooling compared to chlorides. The presence of clay enhances the reticulation of polymer molecules in the blend, which facilitates the carrying of rock cuttings at high temperatures. In addition, regression analyses showed that the increase in temperature resulted in an enhanced tendency for the polymer solution to evolve from a pseudoplastic to a Newtonian type. Conclusion: This research provides theoretical basis and data support for developing high-temperature polymers and formulating high-temperature drilling fluid systems.

Synchronized Falling-Film Devolatilization and Viscosity Enhancement for Continuous Production of High-Strength PA 6 Industrial Yarn

Synchronized Falling-Film Devolatilization and Viscosity Enhancement for Continuous Production of High-Strength PA 6 Industrial Yarn

High-fidelity imaging of drug-induced acute gastritis by using a fluorescent and photoacoustic dual-modal probe with good stability in stomach acid

In consideration of deep tissue imaging and signal fidelity, fluorescent-photoacoustic (PA) dual-modal probes are much more desirable. However, dual-modal imaging of gastritis using molecular probes remains a challenge due to the harsh gastric acid environment in the stomach. Based on the positive correlation between gastritis and cell viscosity, stomach acid-stable and viscosity-activated probes could potentially diagnose gastritis. As a proof of concept, herein, a fluorescent and photoacoustic dual-modal probe (named WSP-1) is revealed for the imaging of drug-induced acute gastritis in vivo. WSP-1 exhibits viscosity-dependent fluorescence emission and photoacoustic signals. A rotatable C–C single bond is incorporated into the D-π-A structure of WSP-1, which could facilitate the formation of the twisted intramolecular charge transfer (TICT) state in a low-viscosity environment (weak fluorescence/PA signal) and the intramolecular charge transfer (ICT) state in a high-viscosity environment (strong fluorescence/PA signal). WSP-1 has demonstrated the capability to target mitochondria and can be utilized to monitor the viscosity enhancement of cells during inflammation. Most importantly, WSP-1 exhibits good optical and structural stability in gastric acid. By leveraging these desirable features of WSP-1, we have achieved fluorescent and 3D photoacoustic in situ imaging of drug-induced acute gastritis following oral administration of WSP-1.

A salt-responsive amphoteric viscosifier for high-density solid-free completion fluids with high temperature resistance, strong solubility, and high viscosity enhancement

There is a lack of viscosity enhancers for high-temperature and high-density solid-free completion solutions in high-temperature and high-pressure oil and gas reservoirs. To address the problem of insufficient temperature resistance of biopolymers and poor performance of conventional viscosifiers in high-temperature and high-density solid-free completion fluids, an anti-temperature viscosifiers for high-density solid free completion fluids was synthesized using N,N-dimethylacrylamide(DMAA), diallyldimethylammonium chloride(DMDAAC) and the amphoteric ion [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium Hydroxide(SBMA) as the main monomers. FPOD has salt-responsive properties. With the increase of brine concentration, the degree of stretching of FPOD molecular chain increased and formed a network structure through intermolecular forces, which provided a viscosity increasing effect on the solution. FPOD has good temperature resistance. The apparent viscosity of 1 wt% FPOD in 1.75 g/cm3 CaBr2 brine was 37 mPa·s, and after aging at 150 °C, the viscosity was still 32.5 mPa·s. The performance of FPOD before and after aging is better than other viscosifiers. FPOD is simple to prepare and has good viscosity enhancement effect in high density solid-free brines. Moreover, FPOD is well-compatible with other treatment agents for completion fluids, and the HTHP filtration loss of the completion fluid system with 2 wt% FPOD added at 150 °C is only 5 mL. FPOD could solve the problem of insufficient high temperature resistance and viscosity increasing performance of viscosifiers in high density brine completion fluids, and provide a new technical approach to drilling high-temperature and high-pressure oil and gas reservoirs.

Effect of multi-donor and extended π-conjugation in ferrocene appended indanedione chromophores for aggregation induced emission enhancement (AIEE) and nonlinear optics†

A new (D-D’π-A) type ferrocene and methoxyphenyl (D-D′) conjugated indanedione (A) based linear and π-extended multi-donor-π-acceptor chromophores 1–4 were synthesized and characterized. The chromophores 2–4 were further investigated by single-crystal analysis through X-ray diffraction, revealing centrosymmetric space groups with non-covalent interactions (inter, intramolecular hydrogen bonding, and C–H…π interactions) and these molecular packing interactions favor SHG efficiencies. Electrochemical studies show the one-electron charge transfer (Fe2+⇌Fe3+) and observed greater redox potential of chromophore 4 than the parent ferrocene due to the substitution effect. The solvatochromic studies in emission spectra resulted in redshift (56–109 nm) for the chromophores 1–4 by increasing the solvent polarities, which indicates higher excited state stabilization relative to the ground state, results effective intramolecular charge transfer process within the chromophores. The occurrence of ferrocene moieties lowers the fluorescence intensities of the chromophores 1–4, which was overcome through aggregation induced emission enhancement (AIEE) studies at 60 % (THF/H2O). The AIEE state also shows 23 times higher quantum yield than the THF solution for chromophore 4. In addition, a thin film using polymethyl methacrylate as a binder shows a significant blue shift with higher emission intensity than those obtained in the solution due to the intermolecular interactions and enhancement of viscosity. The SHG efficiency studied using the Kurtz and Perry powder technique results in a higher value for chromophore 4 (2 times higher than the reference KDP) attribute to the multi donors, acceptor, and extended π conjugation reducing the anti-parallel alignment in the solid state. The computational calculations were done to validate the experimental results using B3LYP/6-31+G** level of theory.

A novel water‐in‐water emulsion drag reducer with instant solubility and viscosity enhancement for slickwater fracturing fluid

AbstractDrag reducers are indispensable components of slickwater fracturing fluids and play a pivotal role in the reconstitution of unconventional oil and gas reservoirs. Water‐in‐water emulsion (W/W) drag reducers have garnered significant attention owing to their rapid dissolution and environmentally benign properties. The solubility and viscosity enhancing ability of W/W drag reducers were further enhanced by synthesizing a novel W/W drag reducer through dispersion polymerization, thereby meeting the requirements of real‐time mixed fracturing construction technology. The solubility, viscosity enhancement, and synthesis state of the synthetic drag reducer were employed as evaluation criteria, whereby the synthetic systems underwent screening and optimization of the synthesis conditions. The final synthetic conditions were determined as follows: the monomer (AM and DMC) had a total mass concentration of 25 wt%, with an AM to DMC molar ratio of 95:5. The dispersion medium (sodium sulfate and sodium chloride) had a total mass concentration of 12 wt%, with a sodium sulfate to sodium chloride mass ratio of 1:2. The dispersion stabilizer PVP K60 had a mass concentration of 7 wt%. The initiator had a total mass concentration of 0.05 wt%, with an ammonium persulfate to sodium bisulfite mass ratio of 1:1. The reaction was conducted at 35°C and a stirring speed of 500 r min−1 for a duration of 8 h. The successful synthesis of the polymer was demonstrated using Fourier transform infrared spectroscopy. Environmental scanning electron microscopy and atomic force microscopy have characterized that the drag reducer has good viscosity enhancement potential. The performance evaluation results show that the solid content of drag reducer was 32.68%, and the residue content was 11.70 mg L−1. The viscosity enhancement rate of 1.3 wt% drag reducer was 93.7%. The dissolution time of 0.1 wt% drag reducer was only 25 s. The drag‐reduction rate of drag reducer reached 73.52%. Experimental results have proved that the drag reducer has the advantages of instant solubility, appreciable viscosity enhancement and drag‐reduction efficiency, fully meeting the real‐time mixing fracturing construction conditions, improving construction efficiency, and reducing construction costs. We expect that this study can broaden the application of W/W drag reducers in unconventional reservoir and provide a theoretical basis for field applications.

-Effects and mechanisms of acrylamide-based polymer containing N-vinylpyrrolidone on drilling fluids at high temperature

The exploration of ultra-deep oil and gas presents higher temperature resistance requirements for water-based drilling fluids. However, the lack of temperature resistance mechanism of drilling fluid polymers limits the development of key materials and drilling fluids. In this paper, by comparing the preparation of acrylamide polymers for drilling fluids, the influence of cyclic monomer N-vinylpyrrolidone (NVP) on the properties of polymers for drilling fluids was investigated, and the mechanism of NVP was deeply discussed. The results show that the NVP-containing copolymer PAAN has superior viscosity enhancement and filtration control in high-temperature drilling fluids. This is mainly due to the fact that PAAN has a more stable and complex polymer chain structure than PAA, the polymer that does not contain NVP, and its thermal stability is improved by 18.6 % up to 268°C. At the same time, NVP provides more adsorption spots, and the high-temperature clay adsorption capacity of PAAN in drilling fluids is increased by more than 66.9 % compared with that of PAA, which improves clay hydration and promotes clay dispersion, and ultimately reduces filtration of drilling fluids and stabilizes drilling fluids at high temperatures by more than 23.7 %. The introduction of NVP and the in-depth analysis of its action mechanism supplemented the anti-temperature mechanism of drilling fluid polymers, aiming to support the research and development of ultra-deep drilling fluid technology.

Rational design of a NIR fluorescent probe and its application in food detection of viscosity and biosystem imaging

Viscosity is one of the most important parameters of liquid foods and shows significant change during food spoilage. It is also an important component of the cell microenvironment and is closely associated with the development of liver injury. In this work, a viscosity-sensitive fluorescent probe named WZ-V based on the twisted intramolecular charge transfer (TICT) mechanism was successfully designed. WZ-V had a large Stokes shift, long wavelength emission, and the fluorescence intensity shows 290-fold enhancement in high viscosity. Probe WZ-V successfully detected viscosity changes caused by food thickeners, as well as in milk, orange juice, and lemonade spoilage processes. This provides a new tool for regulating the viscosity of liquid foods and monitoring viscosity changes during food spoilage. In addition, WZ-V has been successfully applied to image viscosity changes in liver injury, which provides an important reference for the study of liver diseases.

Visualization Experimental Study on In-Situ Triggered Displacement Mechanism by Microencapsulated Polymer in Porous Media

Summary Polymer flooding in deep reservoir profile control presents challenges in balancing injectivity and effective mobility control. To address this, we propose a solution by utilizing a microencapsulated polymer that can be easily injected and thickens over time. However, limited research has been conducted on the flow characteristics and the impact on oil mobilization by such profile control agents. In this study, we approximately simulated the time-varying flow process of microencapsulated polymer through in-situ triggered experiments at high temperature and pressure. The flow characteristics and oil displacement mechanism of the microencapsulated polymer under different trigger times were analyzed, and the displacement efficiency during the triggered viscosity enhancement process in porous media was quantitatively evaluated. The experimental results reveal that microencapsulated polymer exhibits a dual mechanism of near-wellbore reservoir particle temporary plugging and deep formation consistency control mechanisms. The transient aggregation of capsule particles alters the flow path, intensifying after expansion. The interaction between the microcapsule particles and the partially released polymer further enhances the resistance-enhancing property of the solution. The viscosity-enhanced microencapsulated polymer fluid improves the displacement efficiency. Microscopic oil displacement and coreflooding experiments resulted in a decrease in oil saturation of 39.5 and 18.33%, respectively. This study provides valuable microscopic insights into the flow behavior and oil displacement performance of microencapsulated polymer, offering essential guidance for optimizing oil reservoir extraction strategies.

Molecular Dynamics Simulation on Thickening and Solubility Properties of Novel Thickener in Supercritical Carbon Dioxide.

Supercritical CO2 has wide application in enhancing oil recovery, but the low viscosity of liquid CO2 can lead to issues such as poor proppant-carrying ability and high filtration loss. Therefore, the addition of thickening agents to CO2 is vital. Hydrocarbon polymers, as a class of green and sustainable materials, hold tremendous potential for acting as thickeners in supercritical CO2 systems, and PVAc is one of the best-performing hydrocarbon thickeners. To further improve the viscosity enhancement and solubility of PVAc, here we designed a novel polymer structure, PVAO, by introducing CO2-affine functional groups to PVAc. Molecular dynamics simulations were adopted to analyze viscosity and relevant solubility parameters systematically. We found that PVAO exhibits superior performance, with a viscosity enhancement of 1.5 times that of PVAc in supercritical CO2. While in the meantime, PVAO maintains better solubility characteristics than PVAc. Our findings offer insights for the future design of other high-performance polymers.

A chloride diffusion model for cementitious material with pore-solution viscosity enhancement

A promising approach to retard chloride attack has been proposed by increasing the pore solution viscosity in contrast to the traditional methods, but the dependence of chloride diffusion coefficient on viscosity has not been included in the current transport models. This paper presents a model for the diffusion of chloride in cementitious materials based on the viscosity-enhancing behavior of pore solution using viscosity modifying admixtures (VMAs). The parameters affecting the diffusion of chloride in the viscosity-enhancing solution are proposed to be the VMA molecular shape factor and VMA volume fraction based on the Maxwell approximation of spherical inclusions in the effective medium approximation theory. VMA shape factor is modeled with VMA molecular mass as a key variable. VMA volume fraction is calculated as a function of water-cement ratio, hydration age, initial VMA volume fraction, and VMA leaching residual fraction. This chloride diffusion model is developed and validated, which is based on the modification of Fick's second law and takes into account the pore solution viscosity-enhancing behavior and VMA-induced pore coarsening. This model differs from traditional models based on ion transport paths and provides a new reference for concrete durability design in terms of the intrinsic properties of the pore solution.

Cost-effective enhancement of high viscosity modified bitumen anti-aging properties using organic layered double hydroxide/fume silica nanoparticles composite nanomaterials

High-viscosity modified bitumen (HVMB) is prone to thermal-oxidative and photooxidative aging, resulting in pavement diseases. The use of conventional Nano-modifiers to enhance the aging resistance of bitumen is often hindered by high costs, limiting their adoption in widespread applications. This study aims to evaluate the impact of a cost-effective Multi-Dimensional Nano-Composite (MDNC) modifier on the durability of HVMB, which includes organically modified Layered Double Hydroxides (OLDHs) and Fumed Silica Nanoparticles (FSNPs). Additionally, Zero-Dimensional Nanomaterials (ZDNs) such as FSNPs, Nano-SiO2, or Nano-TiO2, in combination with various MDNC modifiers consisting of OLDHs and ZDNs, were also utilized as comparative anti-aging modifiers for HVMB binders. FTIR, XRD, and contact angle tests indicate that LDHs modified with KH560 (OLDHs) exhibit improved hydrophobicity and increased interlayer distance. The temperature sweep test of the unaged binders and the FESEM test of the Nano-modifier indicate that the branched network structure of the FSNPs significantly enhances the high-temperature elasticity of the HVMB binders. Rheological test results have shown that both ZDNs and MDNC modifiers can delay the changes in rheological parameters after aging. Combining FTIR and SARA (Saturates, Aromatics, Resins, Asphaltenes) results, it was found that the combination of OLDHs/FSNPs synergistically inhibited the increase in the content of heavy components in bitumen during thermal oxygen and ultraviolet aging. The enhancement of the HVMB's thermal oxidation aging resistance by OLDHs/FSNPs composite modifiers is primarily due to the multidimensional structure of the composite nanomaterial, which effectively prevents the penetration of oxygen molecules. Meanwhile, the improvement in resistance to ultraviolet aging is mainly due to the absorption and scattering characteristics of FSNPs. Therefore, OLDHs/FSNPs are demonstrated to be a cost-effective multidimensional nano-modifier.

Enhanced Nanoparticle Sensing in a Highly Viscous Nanopore.

Slowing down translocation dynamics is a crucial challenge in nanopore sensing of small molecules and particles. Here, it is reported on nanoparticle motion-mediated local viscosity enhancement of water-organic mixtures in a nanofluidic channel that enables slow translocation speed, enhanced capture efficiency, and improved signal-to-noise ratio by transmembrane voltage control. It is found that higher detection rates of nanoparticles under larger electrophoretic voltage in the highly viscous solvents. Meanwhile, the strongly pulled particles distort the liquid in the pore at high shear rates over 103 s-1 which leads to a counterintuitive phenomenon of slower translocation speed under higher voltage via the induced dilatant viscosity behavior. This mechanism is demonstrated as feasible with a variety of organic molecules, including glycerol, xanthan gum, and polyethylene glycol. The present findings can be useful in resistive pulse analyses of nanoscale objects such as viruses and proteins by allowing a simple and effective way for translocation slowdown, improved detection throughput, and enhanced signal-to-noise ratio.

NIR‐Responsive injectable hydrogel cross-linked by homobifunctional PEG for photo-hyperthermia of melanoma, antibacterial wound healing, and preventing post-operative adhesion

Current therapeutic approaches for skin cancer face significant challenges, including wound infection, delayed skin regeneration, and tumor recurrence. To overcome these challenges, an injectable adhesive near-infrared (NIR)-responsive hydrogel with time-dependent enhancement in viscosity is developed for combined melanoma therapy and antibacterial wound healing acceleration. The multifunctional hydrogel is prepared through the chemical crosslinking between poly(methyl vinyl ether-alt-maleic acid) and gelatin, followed by the incorporation of CuO nanosheets and allantoin. The synergistic inherent antibacterial potential of CuO nanosheets, the regenerative and smoothing effect of allantoin, the extracellular matrix-mimicking effect of gelatin, and the desirable swelling behavior of the hydrogel results in fast wound recovery after photothermal ablation of the tumor. Additionally, the hydrogel can serve as an alternative to sutures owing to its tissue adhesiveness ability, which can further render it the merits for accelerated repair of abdominal lesions while acting as a biocompatible barrier to prevent peritoneal adhesion.

CHIA SEEDS (SALVIA HISPANICA L.): A COMPREHENSIVE LOOK AT THEIR ATTRIBUTES, PHYTOCHEMICAL PROFILE, AND IMPACT ON HEALTH

This article presents a comprehensive review of the characteristics, phytochemical profile and health effects of chia seeds. Chia seeds belong to the Lamiaceae family, and are small, oval and colored seeds that grow in tropical and temperate climates. Chia seeds are rich in protein, fiber, minerals, phenolic compounds and polyunsaturated fatty acids. These nutrients give chia seeds functional properties such as antioxidant, anti-inflammatory, hypolipidemic, hypoglycemic and prebiotic. Chia seeds may play a potential role in the prevention and treatment of chronic diseases such as cardiovascular diseases, diabetes, obesity, digestive system diseases and cancer. Chia seeds can be consumed whole, ground into flour or extracted into oil and added to various foods. Moreover, chia seeds have technological functions such as water retention, emulsification and viscosity enhancement in the food industry. Chia seeds have become a popular functional food in recent years and are being researched. However, more clinical studies and meta-analysis studies are needed on the health effects of chia seeds.

Protein isolates made in the laboratory versus the factory: A case study with mung bean and chickpea

AbstractProtein isolates deliver functionalities such as gelling, emulsifying, and foaming, and many recent publications are reporting the functionality of new protein isolates produced in the laboratory. Laboratory protein isolation processes are quite different to industrial processes, and therefore isolate functionalities are likely to be different. We examined some of the differences between laboratory isolates and commercial isolates of mung bean and chickpea protein (MPBI and CPPI). We tested solubility as a function of pH, dispersibility by static light scattering, and viscosity enhancement in a rapid visco analyzer (RVA). Thermal transitions were evaluated with differential scanning calorimetry (DSC), and powder morphology was examined by scanning electron microscopy (SEM). Laboratory isolates were more soluble (e.g. 54%–57% vs. 5%–45% at pH 8) and dispersible than commercial isolates, with the largest DSC endotherms, indicating the least denaturation. Among commercial isolates, we found large differences in solubility, thermal properties, and viscosity enhancement, and minor differences in dispersibility and powder morphology. The hydration protocol had a strong effect on solubility and DSC results, and a moderate effect on RVA results. Comparisons between isolates produced in different laboratories are currently hampered by the use of nonstandard empirical methods for certain functionalities, and we highlight standardized methods for measuring dispersibility and viscosity enhancement. Protein isolation processes affect isolate functionality via effects on protein denaturation and aggregation, and via the morphology and surface chemistry of isolate powders. This means that findings with laboratory isolates cannot necessarily be extrapolated to commercial counterparts but also indicates the power of process design to modulate isolate functionality.

Revolutionizing protective materials: Ultrahigh peak viscosity through MOF-enhanced shear thickening fluid for advanced soft body armor

The incorporation of shear thickening fluid (STF) into aramid fabric has emerged as a compelling strategy to augment the protective attributes of aramid-based soft body armor. The peak viscosity of STF assumes a pivotal role in shaping the efficacy of this enhancement. In this study, we present an innovation in the design and synthesis of an ultrahigh peak viscosity STF using metal-organic framework (MOF)/SiO2 nanoparticles as the core constituents. The remarkable enhancement in peak viscosity of MOFs/SiO2-based STF, taking ZIF-8 as an exemplary MOFs material, is attributed to the pronounced interparticle contact friction facilitated by the rugged surface morphology of the ZIF-8/SiO2 nanoparticles. Therefore, ZIF-8/SiO2-based STF (62.5 wt.%) demonstrates a peak viscosity approximately 3938 times greater than that of conventional SiO2-based STF (62.5 wt.%). This extraordinary STF formulation has been successfully employed in aramid fabric-based soft body armor, resulting in a significantly advancement in protective performance. Compared to Kevlar fabric impregnated with SiO2-based STF (62.5 wt.%), the utilization of ZIF-8/SiO2-based STF (62.5 wt.%) results in substantial and scientifically significant improvements in key mechanical parameters. These include a notable 15.4 % increase in maximum stabbing force, a remarkable 29.5 % augmentation in maximum yarn pull-out force, a 24.3 % boost in maximum yarn tensile strength, and a 204.5 % enhancement in maximum fabric tensile strength. This research underscores the profound impact of synergizing ZIF-8 and SiO2 within the STF matrix, and significantly improves the protective abilities of SiO2-based STF-impregnated Kevlar fabrics, which provides a new route to design STF-impregnated ballistic fabric with high protective performance.

Thickening supercritical CO2 at high temperatures with rod-like reverse micelles

Earlier studies demonstrated the ability of some fluorinated surfactants to form rod-like reverse micelles with the ability to thicken water/supercritical CO2 (scCO2) mixtures at temperatures below 45 ºC [Langmuir 26 (2010) 83–88. Soft Matter 8 (2012) 7044–7055. Colloids and Surfaces B, 168 (2018), 201–210.]. Such viscosity enhancement of scCO2 is known to increase sweep efficiency for oil recovery with CO2 flooding. However, temperatures of up to ∼100 ºC in conventional reservoirs are much higher than those employed in laboratory studies, and tend to weaken inter- and intra-molecular interactions between surfactant molecules, discouraging rod-like reverse micelle formation. With the aim of designing surfactants which form rod-like reverse micelles and thicken CO2 at high temperatures, this study examined phase behavior, nanostructures of reverse micelles and thickening ability of double ω-hydroperfluorocarbon-tail anionic surfactants in W/scCO2 mixtures at temperatures of 35 - 75 ºC and pressure of 80 - 400 bar with different water-to-surfactant molar ratios (W0). The measured CO2 viscosity increased by 1.9–2.2 × for double-chain surfactants M(di-HCF6)x (counterion Mx+ = Ni2+ and Co2+) at 40 mM, over the experimental temperature range. On the other hand, the shorter chain H(CF2)4CH2 twin-tail surfactants M(di-HCF4)x and Na(di-HCF6) gave only 1.1–1.5 × viscosity enhancements. The maximum thickening ability of M(di-HCF6)2 was at W0 = 10 in the W0 range of 5–20 75 ºC and 350 bar. High pressure and high temperature small-angle neutron scattering (SANS) was used determine the micellar structure in these systems, and rod micelles of aspect ratios of 4.5–6.5 were found. The results clearly suggest that ω-hydroperfluorohexyl-tails and divalent counterions induce the formation of rod-like reverse micelles in W/CO2 mixtures, even at high temperatures commensurate with in-reservoir conditions.