Particle Surface Characteristics Research Articles

Key Control Characteristics of Carbon Black Materials for Fuel Cells and Batteries for a Standardized Characterization of Surface Properties

AbstractCarbon Blacks (CBs) are primarily used in electrocatalysis as support materials for nanoparticulate electrocatalysts. In fuel cells, CBs, catalysts, and proton conductive polymers (ionomers) undergo a dispersion/homogenization process for electrode coating. The interactions between components in dispersion and the surface of CB particles are complex. The surface characteristics of CB particles impact slurry formulation, electrode coating, and the resulting electrode layer, affecting fuel cell and battery performance and durability. This study investigates commercially available CBs such as Vulcan XC72R, Ketjen Black EC‐300J, Ketjen Black EC‐600JD, and Super C65, focusing on application‐relevant key control characteristics (KCCs). The KCCs include physicochemical features like electrical conductivity (electron transport through the catalyst layer, CL), oxygen‐containing surface groups (hydrophilicity/phobicity of the CL, catalyst functionalization), surface basicity/acidity, ionomer adsorption, and particle dispersibility (catalyst ink stability). KCCs are determined by particle bulk electrical conductivity, Boehm titration (BT), isoelectric point (IEP), and Hansen solubility parameters (HSP). HSP, understood as similarity parameters for particles, indicate how nanoparticle surfaces interact with liquids during dispersion. The proposed KCCs serve as a starting point for characterizing CBs and guiding product design to obtain meaningful structure‐property relationships, essential for a successful energy transition.

Fabrication of ZnO-quantum dot hybrid nanocomposites with enhanced light scattering and emission characteristics for micro LED display applications

Herein, a facile method is reported to fabricate a color conversion layer comprised of zinc oxide nanoparticles (ZnO NPs) and quantum dots (QDs) for micro-light emitting diode (μ-LED) displays. Further, 11-mercaptoundecanoic acid (MUA)-treated ZnO NPs (ZnO@MUA NPs) are synthesized via a high-energy ball milling method, which bypasses the need for complex synthesis processes and enables functional groups to attach to the surface, thereby facilitating the formation of ZnO@MUA NPs-QD hybrid composites (ZQCs). The particle size, surface characteristics, elemental composition, and binding energy are analyzed to elucidate the reaction mechanism and to confirm that the fabricated ZQC exhibits a chemically bonded structure. To ascertain the optimal molar concentration for incorporating the QDs, parameters such as QD bonding efficiency, quantity of bonded QDs, interparticle distance, and absolute photoluminescence quantum yield (PLQY) are evaluated as functions of molar concentration. As a result, the optimal molar concentration is found to be 1930 nM, giving a bonding efficiency of 96.8 %, along with the bonded QDs of 1.51 × 1011 per a unit area of 1 mm2 of ZnO NPs and a PLQY of 64.8 %. Furthermore, comprehensive optical analyses are performed to assess the potential of the ZQC as a color conversion material for μ-LED displays, in comparison to the use of pristine QDs and silica NP-QD composites.

An experimental and numerical study of the influence of the additive manufacturing process in packing properties of particles: the printed shape matters

Investigations into the various properties of granular matter composed of particles with defined shapes have gained increasing attention. Additive manufacturing, with its freedom of shape and rapid prototyping capabilities, has significantly contributed to these studies. However, this technique may introduce defects in the manufactured particles, which can significantly affect the properties of granular materials. The extent of these defects on particles of different shapes is investigated here. Particles of various shapes (cube, octahedron, quatropod, stellated octahedron, tetrahedron, and tetrapod) were manufactured and subsequently imaged using micro-Computed Tomography. The surface roughness, solidity, and convexity of the particles were quantified. Discrete element simulations of granular bed porosity, utilizing both idealized and real particle shapes, were conducted with different surface mesh resolutions and frictional parameters. A clear influence of the manufacturing process on the packing properties of 3D printed particles was identified. This influence is not uniform across all shapes and is directly correlated with the particle convexity. For numerical simulations, a shape-dependent correction of particle density and surface characteristics are imperative for each shape under consideration, despite the fact that the particles were manufactured using the same technique and material.Graphic abstract

A Comparative Study on the Interaction Between Protein and PET Micro/Nanoplastics: Structural and Surface Characteristics of Particles and Impacts on Lung Carcinoma Cells (A549) and Staphylococcus aureus.

The interaction between particles and proteins is a key factor determining the toxicity responses of particles. Therefore, this study aimed to examine the interaction between the emerging pollutant polyethylene terephthalate micro/nanoplastics from water bottles with bovine serum albumin. The physicochemical characteristics of micro/nanoplastics were investigated using nuclear magnetic resonance, x-ray diffraction, Fourier transform infrared, dynamic light scattering, and x-ray energy dispersive spectroscopy after exposure to various concentrations and durations of protein. Furthermore, the impact of protein-treated micro/nanoplastics on biological activities was examined using the mitochondrial activity and membrane integrity of A549 cells and the activity and biofilm production of Staphylococcus aureus. The structural characteristics of micro/nanoplastics revealed an interaction with protein. For instance, the assignment of protein-related new proton signals (e.g., CH2, methylene protons of CH2O), changes in available protons s (e.g., CH and CH3), crystallinity, functional groups, elemental ratios, zeta potentials (-11.3 ± 1.3 to -12.4 ± 1.7 to 25.5 ± 2.3 mV), and particle size (395 ± 76 to 496 ± 60 to 866 ± 82 nm) of micro/nanoplastics were significantly observed after protein treatment. In addition, the loading (0.012-0.027 mM) and releasing (0.008-0.013 mM) of protein also showed similar responses with structural characteristics. Moreover, the cell-based responses were changed regarding the structural and surface characteristics of micro/nanoplastics and the loading efficiencies of protein. For example, insignificant mitochondrial activity (2%-10%) and significant membrane integrity (12%-28%) of A549 cells increased compared with control, and reductions in bacterial activity (5%-40%) in many cases and biofilm production specifically at low dose of all treatment stages (13%-46% reduction) were observed.

Transport of polystyrene microplastics in bare and iron oxide-coated quartz sand: Effects of ionic strength, humic acid, and co-existing graphene oxide

This research explored the effects of widely utilized nanomaterial graphene oxide (GO) and organic matter humic acid (HA) on the transport of microplastics under different ionic solution strengths in bare sand and iron oxide-coated sand. The results found transport of polystyrene microplastics (PS) did not respond to the presence of HA in sand that contains large amounts of iron oxide. Compared to bare quartz sand, ionic strength had little effect: <20 % of PS passed through Fe sand columns. There was a significant promotion of PS transport in the presence of GO, however, which can be attributed to the increased surface electronegativity of PS and steric hindrance. Moreover, GO combined with HA significantly promoted the transport of PS in the Fe sand, and transport further increased when the concentration of HA increased from 5 to 10 mg/L. Interestingly, the degree of this increase exactly corresponded to the change in the surface charge of the microplastics, demonstrating that electrostatic interaction dominated the PS transport. Further results indicated that co-existing pollutants had significant impacts on the transport of microplastics under various conditions by altering the surface characteristics of the plastic particles and the spatial steric hindrance within porous media. This research will offer insights into predicting the transport and fate of microplastics in complex environments.

Research Strategies for Precise Manipulation of Micro/Nanoparticle Drug Delivery Systems Using Microfluidic Technology: A Review

AbstractMicrofluidic technology facilitates precise control over fluid mixing and interactions between the components, including self-assembly and precipitation. It offers new options for accurately manufacturing particles and holds significant potential in advancing micro/nanoparticle drug delivery systems (DDSs). Various microchannel/microfluidic chips have been explored to construct micro/nanoparticle DDSs. The precise manipulation of particle size, morphology, structure, stiffness, surface characteristics, and elasticity through microfluidic technology relies on specific microchannel geometrical designs and the application of exogenous energy, adhering to the principles of fluid motion. Consequently, this enables reproducible control over critical quality attributes (CQAs), such as particle size and distribution, encapsulation efficiency, drug loading, in vitro and in vivo drug delivery profiles, Zeta potential, and targeting capabilities, for micro/nanoparticle DDSs. In this review, we categorize microfluidic techniques and explore recent research developments in novel microchannel structures spanning the past 5 years (2018–2023) and their applications in micro/nanoparticle DDSs. Additionally, we elucidate the latest manipulation strategies of microfluidic techniques that impact foundational structures related to the CQAs of micro/nanoparticle DDSs. Furthermore, we offer insights into the industrial applications and challenges microfluidic techniques face in the context of novel micro/nanoparticle DDSs.

Morphological, and Optical Properties of BaTiO3 Nano Particles

Barium titanate (BaTiO3) nano particles have garnered significant attention due to their unique structural, morphological and optical properties, which hold promise for various technological applications. This study presents a comprehensive investigation in to the synthesis potential of BaTiO3 nano particle. The synthesis of BaTiO3 nano particles was achived through various methods, including sol-gel, hydrothermal, and solvothermal routes, with meticulous control over parameters such as temperature, pH, and precursor concentration to tailor the nano particle size and morphology. The structural characterization using techniques such as x-ray diffraction (XRD) revealed the formation of pure –phase BaTiO3nanoparticles with crystallite sizes in the nanometer range, exhibiting a perovskite strucure. Morphological analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) elucidated the morphology, size distribution, and surface chacteristics of the nano particles. The results showcased well –defined, uniform nano particles with controllable sizes and shapes, ranging from spherical to cubic, depending onthe synthesis conditions. futher more, the optical properties ofBaTiO3 nanoparticles were investigated using UV-visible spectroscopy and photoluminescence spectroscopy. The UV- visible spectra exhibited characteristic absorption peaks corresponding to the electronic transitions within the band structure of BaTio3,while photoluminescence spectra revealed emission peaks indicative of defect states with in the nanoparticle. These optical properties were found to be tunable by varying the nano particle size, morphology, and surface characteristics, offering opportunities for optoelectronic and photonic device applications. The key findings of this study underscore the importance of understanding the interplay between synthesis parameters and resulting structural, morphological, and optical properties of BaTiO3 nanoparticles.

Experimental and Computational Studies on Surface Characteristics of Silica Particles Synthesized by Hexamethyldisiloxane Combustion

Experimental and Computational Studies on Surface Characteristics of Silica Particles Synthesized by Hexamethyldisiloxane Combustion

Experimental investigation on parameter optimization of liquid spectral beam splitter for continuous photocatalytic hydrogen production accompanied with photovoltaic power generation under solar full spectrum

Effective utilization of solar energy is of great significance for a sustainable future. Herein, we report a cascade system for hydrogen-electricity co-production (PH-PV) utilizing solar full spectrum. The output performance of the system can be precisely adjusted by controlling certain parameters of liquid spectral beam splitter (LSBS) which contains TiO2 nanoparticle suspension simultaneously generating hydrogen via a photocatalytic reaction process. Typically, the thickness of LSBS, the loading amount of TiO2, the flowrate of suspension and the light intensity have been investigated in detail. It is found that LSBS is necessary in our system as it could ensure the safe operation of PV while the light intensities larger than 8 suns. With the decrease of the thickness or loading amount of photocatalyst, more electricity could be produced by PV module but less hydrogen from PH module. Further increase of above two parameters simultaneously could lead to aggregation and settlement of particle suspension in LSBS, which is detrimental to the optical absorbance of the system. Besides, changing the flowrate will diversify the surface features of particles by shear-induced effect. At optimal flowrate, the particles in LSBS could exhibit oscillation characteristics under synergistic effect of shear force and gravity, which would lead to excellent light absorption and transmittance. Furthermore, an obvious gain for both hydrogen and electricity output and system efficiency could be obtained through increasing light intensity appropriately. Finally, the improved merit function (MF) was employed to evaluate the performance of hybrid system and more obvious effect of flowrate on MF value than other parameters was found. The optimal MF value of 3.07 was reached when flowrate was 60 mL/min. Our work is expected to provide important guidance for the optimization of PH-PV cascade system driven by outdoor direct solar energy.

Influence of different protein contents from several clonal varieties of Hevea brasiliensis latex on the properties of cured natural rubber film using glutaraldehyde (GA) as a curing agent

Natural rubber films were prepared from four different Hevea brasiliensis clones, namely RRIM600, RRIT251, PB235, and BPM24, using the creamed concentrated latex method. The creamed latexes were characterized by their protein content and particle sizes. The rubber particle surface characteristics were monitored using transmission electron microscopy (TEM). It was observed that the particle sizes of all clones varied in the range of 1.0–2.5 µm. Moreover, the RRIT251 clone exhibited higher protein content than the other clones. The influence of protein content on the properties of cured natural rubber (NR) was investigated using glutaraldehyde as a cross-linking agent. Mechanical properties, crosslink density, relaxation behavior, and heat resistance indicated by T90 (temperature scanning stress relaxation, TSSR) were considered. The crosslink density of cured NR increased with higher protein content. This phenomenon can be attributed to the strong formation of rubber chains with GA cross-links through the amino groups of proteins present in rubber molecules. Consequently, Hevea brasiliensis clones with higher protein content facilitate improved crosslink formation within the GA system, resulting in enhanced mechanical and thermo-oxidative degradation properties (T90 from TSSR test).

Anticancer Potential of Hemidesmus indicus-enriched Pt/Au Bimetallic Nanoparticles against Human Breast and Skin Cancer Cell Lines

Background: Worldwide, cancer has become the most disastrous disease, causing an enormous number of deaths in the population. According to GLOBOCON, in the year 2020, there were 1.93 crore cases of cancer reported and 10 million deaths caused by cancer. Methods: Metallic nanoparticles, such as gold, silver, and platinum, which possess properties of bioenvironmental stability, safety, and lower toxicity, have become preferred materials for drug delivery. Bimetallic nanoparticles, in particular, have shown enhanced optical, magnetic, electrical, catalytic, and medicinal properties compared to monometallic nanoparticles. We have developed goldplatinum PtAuBNPs containing H. indicus methanolic extract using a green synthesis approach. The PtAuBNPs were characterized by UV-visible spectroscopy, particle size analysis, zeta potential measurement, and surface characteristics using TEM, XRD, Raman spectroscopy, and DSC. The anticancer activity of PtAuBNPs was investigated using two distinctive cell lines, MCF-7 and B16F10. Results: The change in the colour of the prepared systems after incubation indicated the development of nanoparticles, as analysed by UV spectroscopy. The PtAuBNPs showed a particle size of 243.3 nm and a zeta potential of -14.4 mV. TEM analysis showed the hexagonal and cubic nature of the nanoparticles. XRD analysis indicated the crystalline nature of the nanoparticles. The bimetallic nanoparticles showed greater anticancer activity against the breast cancer cell line (MCF-7) and the skin cancer cell line (B16F10), with IC50 values of 35.52µg mL-1and 30.22 µg mL-1, respectively, which have been found to be lower than the standard 5-FU. Conclusion: The development of PtAuBNPs may pave the way for a new era of enhancing the anticancer activity of herbal extracts through the synergistic effects of gold and platinum metals. The developed PtAuBNPs have been shown to exhibit excellent anticancer activity against skin and breast cancer.

Vibration inducing and airflow guiding coupled tomato pollination method research based on gas–solid two-phase flow model

Supplementary pollination helps to improve yield and quality for tomato planting in greenhouse. Current tomato supplementary pollination methods with vibrator or blower can only realize the vibration induced pollen release without particles guiding. The vibration pollen release inducing and airflow pollen movement guiding coupled tomato pollination method and numeric simulation model were imposed in this paper. Firstly, the numeric simulation model based on gas–solid two-phase flow model of tomato pollination under vibration inducing and airflow guiding was established which considering the shape and surface characteristics of tomato pollen particles. Then, the response surface test of three factors and three levels was conducted using the numerical model by taking airflow angle, airflow start time and airflow velocity as factors, the effective pollination amount as pollination effect evaluation indicators. The test result showed that the maximum effective pollinated pollen particles could be acquired with airflow angle of 12.67°, airflow start time of 519.45 ms and airflow velocity of 0.72 m·s−1. Finally, the movement characteristics of tomato pollen particles in the simulation model were compared with the actual high-speed photography observation. The pollen particles movement trajectories in the simulation model were similar to them in actual observation. And the average movement velocities of the pollen particles moving downward and upward were only 7.59 % and 8.33 % differences between the results in simulation model and in actual observation. The average coverage rate of pollen particles on the stigma was 9.59 % with the vibration inducing and airflow guiding coupled pollination method, which was 85.85 % and 100.63 % relatively higher than vibration pollination and airflow pollination. The results show that vibration inducing and airflow guiding coupled pollination method with the optimized airflow parameters can improve the pollination effect, and the numerical simulation model established in this paper were reliable. The research results in this paper lays a foundation for the design and optimization of tomato pollination method and provides a theoretical basis for the application of gas–solid two-phase flow model in the design of supplementary pollination equipment.

Evaluating uncertainty in particle roughness of coated sand and its implication to coating abrasion

Coated soils have recently been spotlighted for their prospective applications in geotechnical engineering. Prior studies have shown that Polydimethylsiloxane (PDMS) coatings can substantially mitigate surface roughness and have suggested that such coatings may experience abrasion under stress conditions. However, comprehensive studies exploring the impacts of these coatings on particle surface attributes have been scarce. In this work, we scrutinize the surface properties of coated sands with varying mass ratios (MRs), applying probabilistic analysis to account for inherent uncertainty. According to the uncertainty quantification investigation via experimental data, the Gamma distribution is optimal to examine increasing MRs, highlighting a steady decline in surface roughness and corresponding dispersion. Furthermore, a probabilistic assessment of a specific coated sand sample (3% MR) exposed to different stress levels are conducted. The findings suggest that polymer coatings may endure abrasion as stress levels rise, with the average roughness values incrementally converging towards those of natural sands. The detailed examination of particle surface characteristics also unveils the existence of more pronounced peaks and valleys at elevated stress levels, implying significant height variations and evident heterogeneity in surface profiles. Overall, the use of probabilistic analysis techniques provides a more precise understanding of how particle surface properties depend on increasing MRs and their notable dispersion under escalating stress levels. This methodology could be instrumental in probing the mechanical behavior of coated sands, known for their considerable uncertainty.

Study on the Particle Surface Fractal Characteristics of Sulfide Ores

The fractal dimension is widely used in many fields as a parameter to characterize the geometric complexity and geometric distribution relationship of research objects. To study the surface characteristics of sulfide ore particles, the fractal theory was applied to quantitatively characterize the surface fractal dimension Ds of sulfide ore microparticles in three particle size ranges, 60–100 mesh, 100–140 mesh and &gt;200 mesh, based on the area–perimeter method. Using an optical microscope, grain projection images of the particles were obtained. The grain shape and characteristics of sulfide ore particles were studied by means of an image processing system. The results demonstrate that the grain shape of sulfide ore particles can be expressed by fractal dimension, and the particle surface fractal dimension ranges from 2.4392 to 2.5492. It was found that the fractal properties begin to decrease due to the increasing of the particle size. The larger the fractal dimension, the finer the particles are. The fractal dimension of sulfide ore particles can be used as an important indicator of their particle shape distribution characteristics, which can provide important information for further study of the relevant physical and chemical properties of sulfide ore particles and provide a new theoretical method and basis for the adhesion and removal of sulfide ore dust. With the quantitative description of the fractal distribution of sulfide ore particles, a new way to study the adhesive force between particles is offered for further research.

Interaction force mechanism for the improvement of reclaimed soil aggregate stability in abandoned homestead by different organic-inorganic soil conditioners

Reasonable application of organic-inorganic soil conditioners can effectively improve the structure and fertility of reclaimed soil in abandoned homestead. Aggregate stability is an important indicator to evaluate soil structure and fertility, and is largely influenced by soil internal forces (van der Waals attractive force, electrostatic repulsive force, hydration repulsive force) and particle surface properties. However, there are few studies on the influence of different soil conditioners on the reclaimed soil internal forces and its relationship with the aggregate stability. Therefore, we selected six different treatments of organic fertilizer (TO), fly ash (TF), maturing agent (TM), maturing agent + organic fertilizer (TMO), fly ash + organic fertilizer (TFO) and control (CK) to conduct a 5-year field experiment to study the effects of reclaimed soil particle interaction forces and surface characteristics on aggregate stability under the treatment of different soil conditioners. The results showed that with the application of soil conditioners, the soil organic matter (SOM), specific surface area (SSA), surface charge (σ0), cation exchange capacity (CEC), aggregate mean weight diameter (MWD) and Hamaker constant increased gradually, while the pH value decreased slightly. In particular, the MWD under the treatments of TFO and TMO increased by 150.3% and 65.6% respectively compared with that under the CK treatment. With the increasing application of soil conditioners, the electrostatic repulsive force and van der Waals attractive force between reclaimed soil particles increased constantly, but the net resultant force between particles decreased and the net attractive force increased continuously, thus improving the aggregate stability. Therefore, there is a significant negative correlation between the net resultant force among reclaimed soil particles and MWD and CEC. In addition, 10−2 mol L-1 is the critical concentration that affects the reclaimed soil internal force, and the organic-inorganic treatments of TFO and TMO can improve the net resultant force better. In a word, the particle interaction forces are important factors affecting the reclaimed soil structural stability, and this study provides a scientific reference for the rational selection of soil conditioners and its interaction force mechanism in the reclaimed soil improvement.

Assessment and evaluation of Chitosan-Metamizole nanoparticles for the fracture healing and analgesic effect: Preclinical study in rat model.

To assess and evaluate Chitosan-Metamizole nanoparticles for fracture healing and analgesic potential, nanoparticles were formulated using the ionotropic gelation method. The nanoparticles were evaluated for particle size, zeta potential, polydispersity index, loading efficiency, surface characteristics and drug release properties. The analgesic activity was determined in carrageenan-induced arthritic male Wister rats. Further fracture healing potency, mechanical testing, radiographic examination and bone histology of the femur were studied. The drug loading efficiency of 11.38%-17.45%, particle size of 140-220nm, and zeta potential of 19.12-23.14mV were observed with a spherical, smooth appearance. Nanoparticles showed sustained release behaviour over a longer period. Nearly 4-fold inhibition of oedema was observed in animals treated with nanoparticles with excellent fracture healing potential. The femurs treated with nanoparticles required greater force to fracture. Nanoparticles significantly improved the strength and healing process. Histopathological studies showed the potential of nanoparticles in the healing process. The study confirmed the potential of nanoparticles in fracture healing and enhancement of analgesic activity.

Исследование процесса синтеза и свойств наночастиц пентаоксида ванадия

The paper presents results of studying the possibility of synthesizing aqueous dispersions of the vanadium (V) oxide nanoparticles that retain aggregative stability for a long period. The experiments performed resulted in obtaining tubular nanoparticles of the vanadium pentoxide (V2O5) 50 µm long and 5--10 nm in diameter. Wall thickness of the obtained tubes was 1.1 nm. It was experimentally established that type of the acid used was not affecting the resulting nanoparticles size, but was significantly effecting the shelf life. To increase the nanoparticles optimal shelf life, it is proposed to use the hydrochloric acid solutions as the peptizing agent. This method made it possible not only to increase the system stability, but also to raise the nanoparticles concentration up to 1 % of the mass. In the framework of experiments on studying the obtained particles surface characteristics, it was found that nanoparticles in the range of pH = 3.0--4.2 were negatively charged, and aggregation stability was mainly determined by the electrostatic factor. The proposed chemical technology could be used in industrial production of the vanadium pentoxide nanoparticles in various industries

Performance of microenvironment-induced lipase immobilization on diversify surface of magnetic particle

The orientation of the enzyme molecular on the interface of the carrier affects its activity. Therefore, it is very important to controllably induce the orientation of the enzyme on the surface to improve the performance of the immobilized enzyme. Magnetic nanoparticles were used to construct microenvironments with the different surface hydrophobicity and charge characteristics by controlled modification, and those particles with various microenvironments were further used to study their interaction with the lipase. The amount and activity of immobilized enzyme on different magnetic nanoparticles surfaces were studied by physical adsorption and covalent binding. Through the enzyme surface and particle surface characteristics analysis, the possible preferred orientation of enzyme and enzyme conformation on different surfaces were inferred, which well explained the effect of surface induction on enzyme loading and activity. The methods of surface microenvironment regulation and the strategy of controllable induction of enzyme orientation adopted in this study are enlightening for the rational design of immobilized enzyme methods.

Strategic design of gold nanocatalysts for effective photocatalytic organic transformation.

We demonstrate the design strategy of free-standing Au nanocatalysts by correlating their physicochemical characteristics with photocatalytic performance. By tailoring the particle size and surface characteristics, we found that small Au nanocatalysts called Au nanoclusters with discrete energy levels are more effective than large metallic Au nanoparticles, while the microenvironments (e.g., charge status and hydrophilicity/hydrophobicity) around the surface of Au-nanoclusters are crucial in determining the performance. With the optimized Au nanocatalyst, under visible light, decarboxylative radical addition reactions for C-C bond formation (i.e., Giese reaction) were first achieved with high yields and further utilized for the preparation of one of the bioactive γ-aminobutyric acid derivatives, pregabalin (Lyrica®), demonstrating its potential in pharmaceutical applications.

Salt-Responsive Phenol Formaldehyde Resin: Changes of Interface Energy on the Aggregation Process.

Phenol formaldehyde resins (PFRs) as a colloidal oil displacement agent were commonly used to plug pores in crude oil reservoirs for enhanced oil recovery (EOR). The aggregation-dispersion and charging behavior of PFR may affect the rheology and plugging performance of the suspension. To understand the aggregation-dispersion and charge of PFR, turbidity, dynamic light scattering, and electrophoretic light scattering experiments were carried out at pH = 10 with different concentrations of salt solutions (NaCl, MgCl2, CaCl2, NaCl/MgCl2, and NaCl/CaCl2). The aggregation rate and ζ-potential were measured, and the critical coagulation concentration (CCC) and critical coagulation ionic strength (CCIS) were further obtained. Based on the triple-layer surface complexation (TL) model, the adsorption ability of cations and the surface characteristics of the PFR particles were studied, and these differences were explained by interface energy. Thus, Derjaguin-Landau and Verwey-Overbeek (DLVO) theory modified by interface energy was applied to explain the aggregation behavior of PFR particles in different types of ion systems. We concluded that, in the presence of multiple ions, DLVO theory modified by interface energy has good applicability to the aggregation-dispersion of PFR particles.