Surfactant Concentration Research Articles

A Methylene Blue/Sodium Sulfinate Photo‐Initiating System for the Red‐Light Emulsion Photopolymerization of Methyl Methacrylate

AbstractThe emulsion photopolymerization of methyl methacrylate (MMA) using red light is reported. The synthesis of poly(methyl methacrylate) (PMMA) latexes is initiated by irradiation of a new, very efficient red‐absorbing methylene blue (MB)/sodium para‐toluenesulfinate (NapTS) system in the red region (660 nm). Visible, and especially red light penetrates the dispersed medium imposed by the emulsion process better than ultra‐violet photons (UVs). However, emulsion photopolymerizations require the development of fully water‐soluble initiating systems activable by red light, which is still hugely challenging because red photons are much less energetic, therefore generally lead to less efficient photochemical processes. The influence of the surfactant concentration and the solids content is examined over particle sizes and polymerization kinetics. The polymerizations work for solids contents between 10 and 25 wt%, with narrowly distributed particles of average sizes ranging from 40 to 65 nm. Calculations of Mie scattering support the observation that at a given wavelength the larger the particles the lower the penetration. All latexes obtained are slightly blue, which are traced to the regeneration of MB when the latexes are exposed to dioxygen. The dye regeneration enables the reactivation of the photopolymerization process.

Effect of alkyl glucoside concentration on functional group structure and adsorption characteristics of anthracite.

To investigate the influence of different concentrations of surfactants on the adsorption of anthracite, the nonionic surfactant alkyl polyglucoside (APG) was selected. The study examined the adsorption characteristics of different concentrations of APG on the surface of anthracite. The results revealed the existence of two modes of APG adsorption on anthracite. Under the action of 0.06 wt% APG, APG was found to adsorb in a monolayer state on the anthracite surface, with a saturation adsorption capacity of 20.06mg/g. When the solution concentration exceeded 0.14 wt%, APG exhibited a double-layer saturation adsorption state on anthracite, with a saturation adsorption capacity of 71.71mg/g. Molecular dynamics simulations complemented these findings, demonstrating that low concentrations of APG could reduce the mobility of water molecules and enhance the hydrophilicity of anthracite. With an increase in the number of APG molecules, multi-layer adsorption occurred on the anthracite surface, making it more hydrophobic. Therefore, the differences in wettability of anthracite induced by different concentrations of APG were primarily attributed to the spatial distribution of the surfactant at the water/coal interface. This study analyzed the adsorption capacity of the surfactant through adsorption experiments and Fourier-transform infrared spectroscopy (FTIR) experiments. Molecular dynamics simulations were conducted to construct six concentration levels of water/APG/anthracite systems. Various aspects, including APG adsorption configurations, interaction energies, relative concentrations of each component, and the diffusion coefficient of water molecules, were discussed to elucidate the reasons for the differential wettability of anthracite induced by different concentrations of APG.

Magnetic hybrid micelles with controllable structures via interfacial instability-induced confined Co-assembly

Co-assembly of amphiphilic block copolymers (BCPs) and nanoparticles (NPs) is an encouraging route to produce shape-tunable functional hybrid micelles, which can integrate the excellent water stability of BCPs and the versatile functionalities of NPs. In this paper, we present an facile method to prepare magnetic hybrid micelles through confined co-assembly of polystyrene grafted Fe3O4@PS NPs and PS-b-poly(ethylene oxide) (PS-b-PEO) induced by interfacial instability of emulsion droplets. The morphology of hybrid micelles can be regulated by varying the surfactant concentration, weight fraction of Fe3O4 NPs, and block ratio of PS-b-PEO. The distribution of NPs inside the micelles is determined by the ratio (d/L) of the NP diameter (d) to the thickness of PS domain of the micelles (L). When 0.49 ≤ d/L < 0.76, the NPs locate within the cylindrical micelles. When d/L ≥ 0.76, the NPs selectively locate in the spherical micelles. More interestingly, the size-selective loading of NPs in the micelles can be achieved, even mixture of NPs different in size is applied. Moreover, these magnetic hybrid micelles show good biocompatibility and morphology-dependent magnetic resonance responsiveness, which may find potential applications in magnetic resonance imaging.

Desulfurization of Basra Diesel Fuel by Emulsification – Adsorption Processes

In this study, the combined emulsification–adsorption processes were employed for the desulfurization of Basra diesel fuel. A high sulfur diesel fuel of 1.4538 wt% from the Basra refinery was oxidized effectively with H2O2 and Acetic acid (AcOH) as a catalyst to reduce sulfur content to 1.0875 wt% before being emulsified. The emulsification desulfurization (EDS) process using Alkyl benzene sulfonate (ABS) as a surfactant was optimized by 20 trails according to Response Surface Methodology (RSM). A 0.83886 wt% was achieved at the following optimum conditions: Surfactant concentration 20 wt.%, temperature 57.56 ᵒC, and homogenization speed 5695 rpm. The adsorptive desulfurization (ADS) process using activated bentonite clay was carried out in a batch system. The RSM was applied to determine the effect of contact time (1-10 hr), clay mass (5- 20 gm/50ml), and temperature (30-100 ᵒC) on the sulfur removal. Results showed that the sulfur content of 0.57 wt% was achieved at the following conditions: adsorption time 7.18 hrs., temperature 53.3 ᵒC, and clay mass 15.24 gm/ 50ml. The achieved sulfur removal efficiency was 23% and 32% for EDS and ADS respectively. The diesel fuel quality was studied by GC and IREX.

Oil-in-Water Emulsions Probed Using Fluorescence Multivariate-Curve-Resolution Spectroscopy.

Hydrophobic surfaces in contact with aqueous media are omnipresent in nature. A plethora of key biological and physiological processes occur at the interface of immiscible fluids. Besides its fundamental importance, probing such interfaces is rather challenging, especially when one medium is bathed in the other. Herein, we demonstrate a fluorescence-based method that probes the oil-water interface and interfacial processes through surface dielectric perturbations. The fluorescence response of Nile Red is measured in hexadecane in water nanoemulsions. Three major spectral components appear: two from the bulk liquid media (hexadecane and water) and a distinct band at around 640 nm due to the interfacial component. Such spectra are deconvoluted using the multivariate-curve-resolution algorithm, and interface-correlated fluorescence spectra are attained. The influence of anionic sodium dodecylbenzenesulfonate (SDBS) and cationic cetyltrimethylammonium bromide (CTAB) surfactants on the oil-water interface is elucidated with concentration-dependent measurements. A charge-dependent spectral shift is observed. The interface correlated band at 641 nm for bare hexadecane nanoemulsions red shifts in the presence of anionic surfactants, indicating an apparent dielectric increase. In contrast, the same band gradually blue shifts with increasing cationic surfactant concentration, indicating an apparent interface dielectric decrease. Such a method can be utilized to probe alterations at interfaces beyond the oil/water interface.

Modelling the effect of soluble surfactants on droplet deformation and breakup in simple shear flow

A hybrid lattice Boltzmann and finite difference method is applied to study the influence of soluble surfactants on droplet deformation and breakup in simple shear flow. First, the influence of bulk surfactant parameters on droplet deformation in two-dimensional shear flow is investigated, and the surfactant solubility is found to influence droplet deformation by changing average interface surfactant concentration and non-uniform effects induced by non-uniform interfacial tension and Marangoni forces. In addition, the droplet deformation first increases and then decreases with Biot number, increases significantly with adsorption number $k$ and decreases with Péclet number or adsorption depth; and among the parameters, $k$ is the most influential one. Then, we consider three-dimensional shear flow and investigate the roles of surfactants on droplet deformation and breakup for different capillary numbers and viscosity ratios. Results show that in the soluble case with $k=0.429$ , the droplet exhibits nearly the same deformation as in the insoluble case due to the balance between surfactant adsorption and desorption; upon increasing $k$ from 0.429 to 1, the average interface surfactant concentration is greatly enhanced, leading to significant increase in droplet deformation. The critical capillary number of droplet breakup $C{{a}_{cr}}$ is identified for varying viscosity ratios in clean, insoluble and soluble ( $k=0.429$ and 1) systems. As the viscosity ratio increases, $C{{a}_{cr}}$ first decreases and then increases rapidly in all systems. The addition of surfactants always favours droplet breakup, and increasing solubility or $k$ could further reduce $C{{a}_{cr}}$ by increasing average interface surfactant concentration and local surfactant concentration near the neck during the necking stage.

Experimental insight into dynamics of water droplet impacting on solid surface and theoretical prediction for maximum spreading coefficient at low Weber number

The hydrodynamics of a droplet impacting solid surface at low Weber number has been studied comprehensively by using a high-speed camera and a theoretical approach based on the improved models of surface energy and viscous dissipation. The impact process is elucidated by analyzing quantitatively the interface evolution of droplet impact solid surface, and the effects of glycerol solution concentration, surfactant concentration, impact velocity, and wall contact angle on spreading width and rebounding height are extensively investigated, respectively. Four stages, namely, approaching, spreading, retracting and stabilizing stages are identified visually during a complete droplet collision. Increasing the concentration of glycerol solution can simultaneously reduce droplet spreading width and rebounding height. However, improving surfactant concentration or enhancing impact velocity can promote droplet spread but hinder its rebound. Decreasing wall contact angle is beneficial to droplet propagation, whereas disadvantageous to droplet rebound. Both surface energy and viscous dissipation are accurately considered based on a real geometric shape and an improved spreading time at the maximum spreading, and thus a novel theoretical formula for the maximum spreading coefficient of droplet impacting at low Weber number has been developed and proved to have a higher prediction accuracy than the previous models under present experimental conditions.

Cosolvents effect on supercritical CO2 microemulsion containing ionic Liquid: Experiment and simulation

Supercritical carbon dioxide (scCO2) microemulsion containing ionic liquids (ILs) 1-ethyl-3-methylimidazolium acetate ([Emim]Ac) were prepared under mild operating conditions with the help of surfactant branched secondary alcohol ethoxylates (TMN-6) and cosolvents (water and ethanol). Phase equilibrium experiments and molecular dynamics (MD) simulations were conducted from gas-phase system, two-phase system to supercritical system. The conditions of constructing supercritical microemulsion were studied by using self-made phase equilibrium device. The effects of temperature, surfactant concentration, and cosolvent concentration on cloud point pressure (CPP) were studied. The results showed that the transparent and uniform microemulsion could not be formed in gas-phase and two-phase systems. In supercritical system, the proper addition of cosolvent water and ethanol contributed to the formation of microemulsion and the dissolution of ILs. However, the reduction effect of CPP was not obvious or even increased when only water was added. After added water and ethanol simultaneously, not only did the maximum WIL increase to 0.26, but CPP also significantly decreased. MD simulation was conducted to characterize the microstructure of three systems. Furthermore, the gyration radius, radial distribution function (RDF), and hydrogen bond dynamics were calculated to analyze the strengthening mechanism of cosolvents on self-assembly. The simulation results revealed that, water promoted the interaction between hydrophilic groups of surfactants and ionic liquids, while ethanol constructed a hydrogen bonding network between continuous and dispersed phases. Water and ethanol have synergistic effect on the preparation of supercritical microemulsion, which has a good effect on improving the self-assembly rate and aggregate stability.

Treatment of hydrocarbon marine pollution with cloud point extraction

AbstractThe release of hydrocarbons (HC) into the marine environment has serious consequences, both economically and ecologically. This work presents an efficient process to remove HC pollution from seawater: cloud point extraction (CPE), considered to be a reliable, inexpensive, and environmentally friendly method, using the readily biodegradable nonionic surfactants Lutensol ON30 and Tergitol 15‐S‐7. A real salt water sample with a high chemical oxygen demand (COD = 1700 mg O2/L) was thus treated. First, the phase diagrams of the binary systems (water–surfactant), and the pseudo‐binary systems (water–surfactant–HC), were determined. Second, after a 24 h settling time, considered as optimal, the extraction results, that is, residual soluble COD, residual percentage of surfactant in the dilute phase and volume fraction of coacervate at equilibrium, were expressed in terms of temperature and initial surfactant concentration. For each parameter, the results obtained were modeled using the response surface methodology and represented on three‐dimensional diagrams. They show that the COD can be reduced to 10 and 15 mg O2/L, using Lutensol ON30 and Tergitol 15‐S‐7, respectively, under seawater temperature conditions. Finally, it was shown that the surfactant can be recycled. The present work demonstrates that CPE can reduce the HC content of seawater on a laboratory scale.

A static and dynamic analysis of nonionic-based binary surfactant systems for adsorption mitigation in a carbonate reservoir with high salinity

Surfactants are crucial in chemical enhanced oil recovery, but high adsorption onto rocks reduces their efficiency and economic viability. Sacrificial agents, such as alkalis, nanoparticles, and polymers have been investigated to mitigate this issue but they in turn present drawbacks such as poor oil interaction, compatibility issues, pore plugging, and increased costs. Binary surfactant systems, due to their favorable potential synergistic interactions, are proposed as solutions for reducing surfactant adsorption. Static adsorption experiments were conducted to assess the effect of the binary surfactants on adsorption efficiency, and the impact of salinity on the adsorption process equilibrium was also studied. Five core flooding experiments under reservoir temperature (41∘C), reservoir pressure (21 MPa), and high salinity (23.4 wt.%) were conducted to evaluate dynamic adsorption. The surfactant concentrations in supernatant and effluent, after the adsorption process were determined via interfacial tension tests using a spinning drop method. The results showed a significant reduction in surfactant adsorption on carbonate rocks, from 9.99 mg/g-rock to 0.68 mg/g-rock for anionic surfactants and from 5.38 mg/g-rock to 0.19 mg/g-rock for zwitterionic surfactants, with corresponding dynamic reductions of 61% and 89%. Our results were further evidenced by the little to no changes in the differential pH curves in the adsorption process of the binary surfactant systems. This study presents a cost-effective approach for significantly reducing surfactant adsorption on carbonate rocks and aids in designing surfactant formulations for adsorption reduction in high-temperature, high-salinity carbonate reservoirs.

Development of a Quantitative Analysis Method for Fragrances in a Sample Containing High Concentrations of Surfactants (Part II) — Liquid Laundry Detergent —

Development of a Quantitative Analysis Method for Fragrances in a Sample Containing High Concentrations of Surfactants (Part II) — Liquid Laundry Detergent —

Study of self-organization and structural phase transitions in water /AOT / isopropyl myristate biocompatible system

This work reports preparation and characterization of biocompatible sodium bis(2-ethylhexyl) sulfosuccinate (AOT) / water/ isopropyl myristate (IPM) systems. We studied their ability to form various self-organized structures such as microemulsions and liquid crystal templates for producing nanoparticles such as drug delivery vehicles, which play an important role in delivery of various substances. We determined concentration and temperature conditions that allow for forming various structures in this system and characterized the structural phase transition from the microemulsion to liquid crystalline phase, which is important for delivery of bioactive compounds. The parameters of the liquid crystalline phase of the water/AOT/isopropyl myristate system were calculated for the first time in this work. The sizes of microemulsion droplets were determined. To describe molecular motions in the studied microemulsion, self-diffusion coefficients of each component were measured. The values of relative diffusion coefficients demonstrated that reverse microemulsions were observed at AOT concentrations up to 60 % wt. Further increase in surfactant concentration slows down their molecular mobility and results in formation of aggregates with a bimodal size distribution and a subsequent formation of the hexagonal liquid crystalline phase. Geometry of the mesophase and its structure were investigated by X-ray diffraction. The respective phase diagram was plotted and analyzed using the data of polarized light microscopy, dynamic light scattering, and NMR self-diffusion. In this diagram, the areas corresponding to the microemulsion, the liquid crystal phase, and the structural phase transition were identified.The study of the structural phase transition from the microemulsion to liquid crystal will offer a predictive power for characterizing incorporation of drugs and controlling their delivery to target cells. A deeper understanding of the structural changes is necessary to clearly determine the conditions of drug delivery.

Modulating the magnetic properties of Fe3C/C encapsulated core/shell nanoparticles for potential prospects in biomedicine

In the pursuit of alternative and less invasive medical treatments, magnetic nanoparticles (NPs) have gained significant relevance. Iron carbides NPs stand out for their higher saturation magnetizations compared to iron oxides, while maintaining a suitable biocompatibility. In this work, high control is achieved over the composition and morphology of Fe3C/C encapsulated core/shell nanoparticles through fine-tuning of the sol-gel synthesis parameters. Specifically, the impact of decreasing each surfactant concentration added, nt, the same both for oleylamine (ON) and oleic acid (OA), has been explored. A minimum value for such parameter denoted by nt,min. was required to produce pure Fe3C@C NP-composites. For nt < 4 mmol, some minor α-Fe impurities arise, and the effective carburization becomes unstable due to insufficient carbon. The magnetic properties of the materials prepared were optimized by reducing the excess carbon from surfactants, resulting in saturation magnetization values of 86 emu/g. (for pure Fe3C at nt = 5 mmol) and 102 emu/g (for Fe3C and <2 % w.t. of α-Fe impurity at nt = 4 mmol). In view of this, several cytotoxicity studies for different Fe3C@C samples were conducted, exhibiting excellent biocompatibility in cell-based assays, which could lead to potential application at the forefront of biomedical fields.

Tailoring stability in oil-in-water high internal phase Pickering emulsions (HIPPEs) through surface modification of beeswax-based solid lipid particles (SLPs) with various surfactants

As high-performance Pickering stabilizers, the exploration of solid lipid particles (SLPs) for oil-in-water high internal phase emulsions (HIPPEs) has garnered significant interest in the colloid domain, primarily owing to their promising applications in the food industry. Herein, as an underutilized and cost-effective food processing resource, beeswax (BW) was probed, and BW-SLPs was tuned by controlling the different type (Na-Cas or T80)/concentration (0.5–2.5 wt%) of surfactant with a view to stabilizing the HIPPEs (φ = 0.80) more effectively. At concentrations of 0.5–2.0 wt%, a more stable semi-solid HIPPEs could be formed by Na-Cas-BW-SLPs, while phase separation occurred at 2.5 wt%. However, T80-BW-SLPs could only form the fluid dynamic emulsions. The correlation between the interfacial characteristics of SLPs and the physical properties of SLPs-stabilized HIPPEs was thoroughly investigated. Microscopic images showed that Na-Cas-BW-SLPs formed a closely packed three-dimensional network structure around the oil droplets but aggregated in the aqueous phase at the concentration of 2.5 wt%. And they exhibited the capacity to improve the viscoelasticity of the interfacial film, which also endowed the HIPPEs with excellent rheological properties. While, T80-BW-SLPs were loosely arranged, formed a viscous film on the interface, and G′ of the interfacial film was about 2 orders of magnitude lower than Na-Cas-HIPPEs at the same concentration. Besides, transmission electron microscopy (TEM) analysis revealed that the Na-Cas-BW-SLPs (∼370 nm), unlike the out of shape T80-BW-SLPs (∼230 nm), exhibited a cross-linked structure with a rough surface. All SLPs demonstrated enhanced wettability and a remarkable ability to reduce interfacial tension (2 mN/m). Additionally, it further identified the inability to form stable HIPPEs up to φ = 0.84 at the optimal Na-Cas-SLPs concentration. Ultimately, the HIPPE stabilized by 3.0 wt% BW and 2.0 wt% Na-Cas, with oil fraction up to 83 vol%, exhibited the highest elastic modulus (3871.0 Pa) and demonstrated exceptional stability over a 30-day storage period.

Bead Size and Rheological Properties of SEBS-Based Elastic Beads

Abstract Styrene-ethylene-butylene-styrene, (SEBS), is a thermoplastic elastomer that has applications in robotics and shock absorption. While SEBS as a bulk material as well as an additive to solid composites has been extensively studied, this work focuses on developing SEBS-based beads to enhance material, particularly fluid, elasticity; the first time this has been seen in literature. SEBS bead mixtures were developed by mixing SEBS elastomer, water, and surfactant (Triton X-100) at high temperature. Stability, rheology, and microscopy of SEBS bead mixtures were studied as a function of neat SEBS concentration in SEBS elastomer, SEBS elastomer concentration, and surfactant concentration. Resulting bead mixtures were classified as creamed, homogenous and stable, or aggregated bead mixtures based on the mixture's tendency to separate into layers and ability to disperse in excess water. Microscopic studies suggest that while bead mixtures exhibit size polydispersity, the average bead size is a strong function of neat SEBS, SEBS elastomer, and surfactant concentrations. Rheological studies suggest that all the bead mixtures exhibit shear thinning behavior, and the overall viscosity of a given bead mixture is a function of both SEBS elastomer and surfactant concentration. The developed SEBS elastic beads can be used as additives to enhance the viscoelastic properties of fluid-based systems like magnetorheological and damping fluids.

More Biosurfactants and Fewer Synthetic Surfactants to Improve Alkali-Surfactant-Polymer Flooding: Feasibility Study and Large-Scale Field Application

Summary Alkali-surfactant-polymer (ASP) flooding has achieved highly enhanced oil recovery (EOR) in the Daqing Oil Field; however, there are concerns about synthetic surfactants owing to their high cost and difficulty in biodegradation. Cheap biosurfactants conform to human concepts of green circular economy; however, known biosurfactants, as well as their mixtures with alkali, cannot reduce water/oil interfacial tension (IFT) to ultralow values below 0.01 mN/m, which is necessary for ASP flooding to effectively mobilize residual oil. Therefore, we investigate the feasibility of partially replacing synthetic surfactants with biosurfactants rather than completely replacing them to improve ASP flooding. First, through a series of IFT tests, a blend of rhamnolipids (RLs) and alkylbenzene sulfonate (ABS) in a 1:1 mass ratio is determined to be the optimal mixed surfactant and labeled RL/ABS-opt. Second, the interfacial activities, phase behaviors, and wettability alteration capabilities of ASP solutions with RL/ABS-opt are studied. Then, 1.0 wt% NaOH and 0.2 wt% RL/ABS-opt are determined to construct a new ASP system. Subsequently, the waterflooded cores are displaced using the new and the classical ASP systems. Based on the promising experimental results, the new ASP system floods a test block of 56 wells for 3 years. The EOR and surfactant costs are calculated to determine the technical and economic effects. Finally, the concentrations of surfactants before and after activated sludge treatment (AST) are tested by spectrophotometry to verify the biodegradability of RLs better than that of ABS. The laboratory and field results indicate that more biosurfactants and fewer synthetic surfactants could improve ASP flooding to be more environmentally friendly and cost-effective with a higher EOR.

SDS and TX-100 performance in removing Cd ion from contaminated sand in flushing column

In this study, contaminated sand by cadmium (Cd2+) ion was cleansed by surfactant foam in a flushing column. The ability to remove Cd2+ ion on the sand surface influenced by the surfactant's properties. The Sodium dodecyl sulfate (SDS) as an anionic surfactant was compared with Triton X-100 (TX-100) non anionic surfactant in their ability to remove the metal ion on the sand surface in the flushing column. The loading time, surfactant concentration, and flow rate of the surfactant were then investigated to confirm the charging effect of surfactant in the ability to remove metal ions. The results show that SDS has a higher ability than TX-100 to remove the Cd2+ ion on the sand surface. The optimal removal efficiency by SDS was 52 %, and TX 100 was 47 %. The loading time impacted surfactant interaction with metal ions in the column, showing that a longer loading time will increase the removal efficiency. Increased concentration of surfactants and more prolonged initial flushing tend to remove higher metal ions, indicating that the residual metal ion was flushing out on the first four pore volume removals. Flushing in a column with foam by anionic surfactant shows a higher ability to remove metal ions on the sand surface.

New Cationic Gemini Surfactants and Their Use as Dispersants in Oil-in-Water (O/W) Emulsions

In the current research, two types of new cationic gemini surfactants with different spacers (aromatic and heterocyclic) derived from epichlorohydrine were prepared. The prepared compounds were characterized using FTIR and 1H-NMR spectroscopy. Then the value of critical micelle concentration CMC was calculated using the electrical conductivity and preparing a series of molar concentration of the new surfactants, as well as calculating the balance value between the hydrophilic and hydrophobic (lipophilic) HLB groups. Cationic gemini surfactants were tasted at different concentration 20-40 ppm by preparing dishes for oil-in-water emulsions determine their dispersion efficiency. It was observed that the dispersant containing the heterogeneous ring (MS1) was more efficiently dispersed than the surfactant containing the aromatic ring (MS2) in the presence of the same hydrocarbon chain and at a concentration of 40 ppm.

Facile Synthesis of Surface-Modified Hollow-Silica (SiO2) Aerogel Particles via Oil-Water-Oil Double Emulsion Method.

Due to their high surface area and low weight, silica aerogels are ideally suited for several uses, including drug delivery, catalysis, and insulation. Oil-water-oil (OWO) double emulsion is a simple and regulated technique for encasing a volatile oil phase in a silica shell to produce hollow silica (SiO2) aerogel particles by using hydrophilic and hydrophobic emulsifiers. In this study, the oil-water-oil (OWO) double emulsion method was implemented to synthesize surface-modified hollow silica (SiO2) aerogel particles in a facile and effective way. This investigation mainly focused on the influence of the N-hexane-to-water glass (OW) ratio (r) in the first emulsion, silica (water glass) content concentration (x), and surfactant concentration (s) variations. Furthermore, surface modification techniques were utilized to customize the aerogel's characteristics. The X-ray diffraction (XRD) patterns showed no imprints of impurities except SiO2. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images highlight the hollow microstructure of silica particles. Zeta potential was used to determine particle size analysis of hollow silica aerogel particles. The oil-water-oil (OWO) double emulsion approach was successfully employed to synthesize surface-modified hollow silica (SiO2) aerogel particles, providing precise control over the particle characteristics. By the influence of the optimization condition, this approach improves the aerogel's potential applications in drug delivery, catalysis, and insulation by enabling surface modifications.

Unveiling the swelling behavior of κ-carrageenan hydrogels: Influence of composition and physiological environment on drug delivery potential

This study aims to develop a biodegradable hydrogel wound dressing film based on carrageenan and agar loaded with tetracycline (TC), which exhibits high antibacterial properties and accelerates wound healing. The swelling behavior of κ-carrageenan/agar and tetracycline-loaded hydrogel films was examined, with a focus on the hydrogel’s efficacy in various physiological fluids, as well as the effects of polysaccharide ratio, cross-linker concentration, and surfactant concentration. The results revealed that the polysaccharide ratio significantly influenced the hydrogel swelling capacity of hydrogel, and a 1:1 ratio of agar to κ-carrageenan achieved the highest swelling degree of 1386 %. Addition of KCl, as a cross-linker, increased swelling capacity to 1713 %. Furthermore, surfactant concentration also influenced swelling behavior, and higher concentrations resulted in an increase in hydrophilicity and swelling. Hydrogel swelling performance varied across physiological fluids, with the highest and lowest swellings observed in deionized water (DIW) and simulated wound fluid (SWF), respectively. The swelling process in DIW and phosphate buffered saline (PBS) exhibited second-order kinetics, whereas non-Fickian diffusion mechanisms were observed in SWF. The drug release of the κC/AG/TC hydrogel film was controlled by its swelling capacity and the pH of medium. The hydrogels’ mechanical properties, antibacterial activity, and water vapor permeability were also investigated.