Nonionic Polymeric Surfactants Research Articles

Sustainable conversion of polystyrene waste into polymeric surfactants to be evaluated as pour point deperssants for waxy crude oil

Disposing of polystyrene trash is an environmental concern, and converting it into value-added products is appealing . This research study focuses on implementing a sustainable method to convert polystyrene waste into polymeric nonionic surfactants. The polymeric nonionic surfactant additives were prepared by grafting polystyrene waste (WPS) with a methacrylic monomer (MMA), followed by an esterification reaction with polyethylene glycol of different molecular weights (400 and 1000). The chemical composition of the synthesized compounds was justified by spectroscopic analysis. Interfacial tension (IFT) was investigated to gain insights into the behavior of the polymeric nonionic surfactants produced at the interface. The modified waste polymers were evaluated as pour depressants and paraffin inhibitors. Additionally, the rheological properties of the modified waste polymers were examined. The findings revealed that, the IFT between oil and water decreased from 21 to 7 mN/m for WSPA400 and even further to 4 mN/m for WSPA1000. At a concentration of 500 ppm, WPSA1000 exhibited the maximum depression effect than WPSA400, reducing the pour point temperature from 27 °C to 12 °C and 3 °C, respectively. Also, At 500 ppm, the amount of wax deposition declined from 8.5 g to 1.90 g and 0.95 g after treating the crude oil with WPSA 400 and WPSA 1000. The rheological measurements further revealed that the WPSA1000 additive outperformed the WPSA400 additive in terms of enhancing the fluidity of oil. In order to acquire a more comprehensive understanding of the mechanisms involved in pour point depression, the utilization of polarizing optical microscopy was used to explore the effect of WPSA1000 as a pour point depressant.

Improved biological methanation using tubular foam-bed reactor

BackgroundPower-to-gas is the pivotal link between electricity and gas infrastructure, enabling the broader integration of renewable energy. Yet, enhancements are necessary for its full potential. In the biomethanation process, transferring H2 into the liquid phase is a rate-limiting step. To address this, we developed a novel tubular foam-bed reactor (TFBR) and investigated its performance at laboratory scale.ResultsA non-ionic polymeric surfactant (Pluronic® F-68) at 1.5% w/v was added to the TFBR’s culture medium to generate a stabilized liquid foam structure. This increased both the gas–liquid surface area and the bubble retention time. Within the tubing, cells predominantly traveled evenly suspended in the liquid phase or were entrapped in the thin liquid film of bubbles flowing inside the tube. Phase (I) of the experiment focused primarily on mesophilic (40 °C) operation of the tubular reactor, followed by phase (II), when Pluronic® F-68 was added. In phase (II), the TFBR exhibited 6.5-fold increase in biomethane production rate (MPR) to 15.1 (LCH4/LR/d)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$({\ ext{L}}_{{\ ext{CH}}_{4}}\ ext{/}{\ ext{L}}_{\ ext{R}}\ ext{/d)}$$\\end{document}, with a CH4 concentration exceeding 90% (grid quality), suggesting improved H2 transfer. Transitioning to phase (III) with continuous operation at 55 °C, the MPR reached 29.7 LCH4/LR/d\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{L}}_{{\ ext{CH}}_{4}}\ ext{/}{\ ext{L}}_{\ ext{R}}\ ext{/d}$$\\end{document} while maintaining the grid quality CH4. Despite, reduced gas–liquid solubility and gas–liquid mass transfer at higher temperatures, the twofold increase in MPR compared to phase (II) might be attributed to other factors, i.e., higher metabolic activity of the methanogenic archaea.To assess process robustness for phase (II) conditions, a partial H2 feeding regime (12 h 100% and 12 h 10% of the nominal feeding rate) was implemented. Results demonstrated a resilient MPR of approximately 14.8 LCH4/LR/d\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{L}}_{{\ ext{CH}}_{4}}\ ext{/}{\ ext{L}}_{\ ext{R}}\ ext{/d}$$\\end{document} even with intermittent, low H2 concentration.ConclusionsOverall, the TFBR’s performance plant sets the course for an accelerated introduction of biomethanation technology for the storage of volatile renewable energy. Robust process performance, even under H2 starvation, underscores its reliability. Further steps towards an optimum operation regime and scale-up should be initiated. Additionally, the use of TFBR systems should be considered for biotechnological processes in which gas–liquid mass transfer is a limiting factor for achieving higher reaction rates.

Non-ionic Polymeric Surfactants of Fatty-Polyethylene Glycol-L-Cysteine as Acid Corrosion Inhibitor

Non-ionic Polymeric Surfactants of Fatty-Polyethylene Glycol-L-Cysteine as Acid Corrosion Inhibitor

THE EFFECT OF SURFACTANT ON PRE-MORDANTING AND pH OF DYEING PROCESS WITH NATURAL DYES

The dyeing process with natural dyes has disadvantages, including poor color fastness. A mordanting process is required to overcome these disadvantages. Conventional mordanting processes often use metal salts. This research will substitute the mordanting process using surfactants as mordant substances. The pH of the process influences the application of dyeing with natural dyes. This study aims to determine the effect of the pre-mordant process using surfactants and the pH of the dyeing process on the color characteristics of cotton and silk fabrics dyed with Cocos nucifera L dye extract. The surfactants used were cationic and non-ionic polymeric surfactants. This study was conducted in phases. The first phase involved the extraction of coconut fiber, and the second phase involved pre-mordanting the fiber with surfactants. The third stage is the dyeing process, which has variations in pH 3, 7, and 9. The evaluation results show that cationic surfactants have the potential to be used as a mordant and provide an increased anti-bacterial effect on processed fabrics. The optimal use of cationic surfactants was obtained using a concentration of 9 g/L and pH 7 for the cotton dyeing process. The optimum concentration was obtained at 9 g/L for the silk dyeing process, and the dyeing pH was 3.

Design of novel aqueous two-phase systems to be coupled in biological remediation processes

The ability of a biodegradable Deep Eutectic Solvent (DES) reline to induce phase segregation in aqueous solutions of polymeric non-ionic surfactants (Tween 20 and Tween 80) has been demonstrated as a preliminary step to be employed for assisting a biological degradation process of a model contaminant. The binodal curves for systems composed of (surfactants + reline + Water) have been determined at several temperatures, and the experimental data have been correlated using well-known equations. The equilibrium data have been analysed in the light of the operating temperature and the hydrophobicity of surfactants. Tie-lines of these systems have been determined, together with useful parameters such as tie-line length and tie-line slopes. Othmer-Tobias and Bancroft equations have been applied to provide an adequate description of the equilibrium data. Finally, the application of this new approach for the remediation of aqueous polluted effluent has proven to be highly efficient, with extraction percentages exceeding 99% for two model persistent contaminants (Acid Black 48 and Crystal Violet). Consequently, this ATPS is proposed as an extra-stage to enhance the remediation percentages achieved through biological methods. Furthermore, the process has been simulated using commercial software.

Block Copolymers of Ethylene Oxide and Propylene Oxide: Prospects for Medical and Pharmaceutical Application in Russia

Block copolymers of ethylene oxide and propylene oxide (EO/PO block copolymers) are polymeric non-ionic surfactants with a high hydrophilic–lipophilic balance also referred to as pluronics, poloxamers, or proxanols. These compounds are among the most demanded modern excipients for the production of medicines. EO/PO block copolymers are used both in the production of traditional (liquid, semi-solid, and solid) dosage forms and as part of targeted delivery systems. The extensive application of EO/PO block copolymers is due to the diverse array of their properties, including not only solubilising, emulsifying, gelling, and other effects but also thermoreversibility, which is essential for developing in situ delivery systems and 3D printing technologies.The aim of the study was to evaluate the potential of EO/PO block copolymers for medicinal use and to assess the range of medicinal products approved in the Russian Federation that contain EO/PO block copolymers.This review presents an analysis of the register of poloxamer-containing medicines approved in the Russian Federation, a list of the largest manufacturers of EO/PO block copolymers in the world, and a study of the possibility to use copolymers for medical purposes. Currently, there are more than 10 chemical manufacturers producing EO/PO block copolymers for the pharmaceutical, biotechnology, and other industries around the world. EO/PO block copolymers are included in more than 60 medicinal products present in the Russian pharmaceutical market; this observation indicates the need to phase out the import of poloxamers.

Development and evaluation of azithromycin dihydrate in single and binary micellar mediums

Azithromycin (AZI) has poor aqueous solubility and very low bioavailability. In this study, two nonionic polymeric surfactants, namely Pluronic L-35, and Pluronic P-123, and their binary micelle was used for entrapment of drug AZI. The drug-encapsulated micelles were characterized by UV-spectrophotometry, FTIR, Cloud point, Partition coefficient, and antibacterial studies. We observed improved solubilization of the drug AZI in the binary micellar formulation than in their single micellar systems. The FTIR studies inferred that there is a stable, strong bond formation of the drug AZI with the binary micelle. The partition coefficient values too pointed towards higher solubility of drug AZI in mixed micellar systems as compared to single micellar systems. The free energy of micellization ∆Gomic as determined from the partition coefficient displayed negative values for all three systems indicating spontaneous binding between the drug AZI with the polymeric micellar systems. The highest negative value (-3192.6 kJ/mol) for AZI in the binary system compared to AZI-L-35 (-1620.3 kJ/mol) and AZI-P-123 (-2752.8 kJ/mol) concludes that the drug AZI is better partitioned in the binary micellar system than in the two single micellar solutions. This study can be considered as a potential solubilizing medium for the drug AZI. This is probably the first report of AZI in binary micellar solution.

Synthesis, characterization, and evaluation of polymeric surfactants derived from PET plastic waste as green corrosion inhibitor of steel surfaces in marine environment for heavy industry.

The aim of this work was to prepare a nonionic polymeric surfactant from a recycled product of poly(ethylene terephthalate) plastic waste, PET. In this respect, PET waste was subjected to reverse polymerization (depolymerization) via reaction with both ethylene diamine (EDA) in the presence of a catalyst and propylene glycol (PG) in the presence of a transesterification catalyst. The corresponding products obtained were poly amino amide (PETAA) and poly glycol ester (PETPG), respectively. The obtained materials reacted with oleic acid to produce N1,N4-bis(2-((E)-octadec-9-enamido)ethyl)terephthalamide (PETAA-OL) and 2-(2-(((E)-octadec-8-enoyl)oxy)propoxy)ethyl (2-(2-(((E)-octadec-9-enoyl)oxy)propoxy)ethyl) terephthalate (PETPG-OL). The prepared materials were characterized by FT-IR, 1HNMR, and elemental analysis. It was evaluated as a corrosion inhibitor for carbon steel used in the petroleum industry in the marine environment. Chemical, analytical, and electrochemical techniques were used for the evaluation of the corrosion inhibition efficiency of the prepared polymeric surfactants. The effects of the polymeric surfactant concentration and reaction temperature were studied. The inhibition efficiency was found to increase with increasing concentration and decrease with rising temperature. The inhibition due to the adhesion and adsorption of the polymeric material on the steel surface agrees with the Langmuir adsorption isotherm model. The amount of dissolved iron in the corrosive medium due to the corrosion process was estimated using atomic absorption spectroscopy (AAS). It was found that the dissolution of iron was decreased by adding the prepared nonionic surfactants. Potentiodynamic polarization data indicate the mixed-type nature of surfactant inhibitors. According to the potentiodynamic polarization data, the prepared surfactant boosts polarization resistance and inhibition performance by adsorbing on the metal/electrolyte interface. The addition of inhibitor molecules to the aggressive medium produces a negative shift in the open-circuit potential due to the retardation of the cathodic reaction. The surface morphology of steel was examined using SEM. A protective coating of inhibitor molecules forms on the steel surface, according to the SEM measurements of the surface. The data obtained from different techniques are in good agreement, indicating good inhibition efficiency of the prepared nonionic surfactants derived from plastic waste in a marine environment.

Curcumin nanoparticles combined with 3D printed bionic tumor models for breast cancer treatment

Compared with conventional therapeutic approaches, nanomedicines are attracting a growing interest due to their better targeting ability, higher delivery efficiency, and good water solubility. However, conventional drug efficacy assessment methods are based on a two-dimensional (2D) culture approach of single cells to obtain in vitro therapeutic effects, which may not be representative of actual tumors. Based on the above considerations, the three-dimensional (3D) cell culture models became a better choice since they can increase the complexity of in vitro systems and provide a biomimetic microenvironment that is closer to the in vivo native than 2D cultures. In our study, curcumin nanoparticle (CurNPs) with good water solubility and good tumor therapeutic effects were prepared by combining polymeric non-ionic surfactant (Pluronic F127) with curcumin. The hybrid scaffolds based on nano-clay, sodium alginate, and gelatin were also prepared, which showed good printability and excellent biocompatibility. We then studied the therapeutic effects of CurNPs on metastatic breast cancer using a 3D tumor model fabricated with scaffold-bound metastatic breast cancer (MDA-MB-231) cells. It was showed that the 3D cell model presented better cell proliferation effect while compared with 2D version. Additionally, there was good enhanced permeability and retention effect when CurNPs entered with better accumulate in 3D cell ‘tumor’ sites which represented more realistic response of a more real tumor treatment effect for breast cancer cells. Our study indicated that the combinational of nanomaterials with 3D cell ‘tumor’ models provided an alternative and better platform for drug screening and has great potential be used as safe and effective treatment screening for breast cancer.

Synthesis, Characterization, and Performance of New Polymeric Nonionic Surfactants as Flow Improvers and Wax Dispersants for Waxy Crude Oil

Synthesis, Characterization, and Performance of New Polymeric Nonionic Surfactants as Flow Improvers and Wax Dispersants for Waxy Crude Oil

Sustained Release of a Polymeric Wetting Agent from a Silicone-Hydrogel Contact Lens Material.

Uptake and release kinetics are investigated of a dilute aqueous polymeric-surfactant wetting agent, (ethylene oxide)45—(butylene oxide)10 copolymer, also referred to as poly(oxyethylene)-co-poly(oxybutylene), impregnated into a newly designed silicone-hydrogel lens material. Transient scanning concentration profiles of the fluorescently tagged polymeric surfactant follow Fick’s second law with a diffusion coefficient near 10–11 cm2/s, a value 3–4 orders smaller than that of the free surfactant in bulk water. The Nernst partition coefficient of the tagged polymeric wetting agent, determined by fluorescence microscopy and by methanol extraction, is near 350, a very large value. Back-extraction of the polymeric-surfactant wetting agent releases only ∼20% of the loaded amount after soaking the fully loaded lens for over 7 days. The remaining ∼80% is irreversibly bound in the lens matrix. Reverse-phase liquid chromatography of the lens-loaded and lens-extracted surfactant demonstrates that the released wetting agent is more hydrophilic with a higher polarity. Aqueous poly(oxyethylene)-co-poly(oxybutylene) is hypothesized to attach strongly to the lens matrix, most likely to the lens silicone domains. Strong binding leads to slow transient diffusion, to large uptake, and to significant irreversible retention. These characteristics indicate the suitability of using a poly(oxyethylene)-co-poly(oxybutylene) nonionic polymeric surfactant to maintain enhanced lens wettability over time. Methodology and findings from this study provide useful insights for designing sustained-release contact-lens wetting agents and materials.

Surfactant induced bilayer-micelle transition for emergence of functions in anisotropic hydrogel.

Tuning the self-assembled structures in amorphous hydrogels will enrich the functionality of hydrogels. In this study, we tuned the structure of a photonic hydrogel, which consists of polymeric lamellar bilayers entrapped inside a polyacrylamide network, simply by molecular triggering using an ionic surfactant. Owing to the binding of ionic surfactants (sodium dodecyl sulfate), the lamellar bilayers comprising non-ionic polymeric surfactants [poly(dodecyl glyceryl itaconate)] changed to micelles, whereas the unidirectional lamellar structure was preserved in the hydrogel. The bilayer-micelle structure transition caused a dramatic decrease in the swelling anisotropy and mechanical softening of the photonic gel. With the micelle structure, the softened gel shows fast (0.3 s) and reversible color change over the entire visible light range in response to a small mechanical pressure (5 kPa). This low stress-induced color-changing hydrogel could be applied as a visual tactile sensor in various fields, especially in biomedical engineering.

Polymer/surfactant mixtures as dispersants and non-covalent functionalization agents of multiwalled carbon nanotubes: Synergism, morphological characterization and molecular picture

While surfactants and polymers have been independently investigated as agents to separate, disperse and stabilize carbon nanotubes (CNTs) in water, mixed polymer/surfactant (P/S) systems have been far less studied for those ends. In this work, we investigated the ability of various types of P/S mixtures to effectively separate multiwalled carbon nanotubes (MWNTs) in water, using rigorously controlled processing conditions. Two types of mixtures were explored: i) nonionic polymer (PVP, polyvinylpyrrolidone) and ionic surfactant (sodium dodecylbenzene sulfonate, SDBS, or cetyltrimethylammonium bromide, CTAB); and ii) ionic polymer (poly(diallyl dimethyl ammonium chloride), PDDA, and sodium polyacrylate, PAS) and nonionic surfactant (TX-100). Detailed, high precision dispersibility curves (concentration of dispersed nanotubes vs. total P/S concentration, at fixed S concentration) are presented for four P/S mixtures (PVP/SDBS, PVP/CTAB, PDDA/TX-100 and PAS/TX-100) and their respective individual components. Quantitative metrics extracted from the dispersibility curves allow for reliable comparisons between the systems. In all P/S mixtures, beneficial (synergistic) effects in nanotube dispersibility are observed compared to the individual components, with the exception of the PDDA/TX-100 one for which a detrimental (antagonistic) effect occurs. Morphological characterization of the as-obtained dispersions by scanning electron microscopy (SEM) shows a significant degree of nanotube separation by the P/S systems. Surface tension and zeta potential measurements provide further information on the interactions at play between the MWNTs and the P/S mixtures, allowing to conceive plausible mechanisms for the synergistic effects observed. P/S association may not only offer conditions for an enhanced dispersibility of CNTs but also expand the types of noncovalent, reversible functionalization required in many applications, such as the development of nanocomposite particles, films and coatings.

Antimicrobial activity of polymeric surfactants blending with zinc oxide nanoparticles derived from Electric Arc Furnace Dust

The biological activities of poly (ethylene glycols) (PEG) that esterified with lauric acid or myristic acid were enhanced by mixing with zinc oxide nanoparticles (ZnO-NPs) derived as of hazardous trash Electric Arc Furnace Dust (EAFD) which formed through steel fabrication using sodium hydroxide (NaOH). A diverse temperature was applied to characterize and examine the prepared polymeric surfactants those possess characteristics of surfactant and polymer together. The surface properties were measured and worked out. The hydrodynamic particle diameter normally maximized as the surfactant carbon numbers increased and at blending with ZnO-NPs as exhibited in the dynamic light scattering (DLS) statistics due to aggregation of molecules. The antimicrobial action against different microorganisms of all such designed structures was assessed and assigned. The results plain that, all such engineered nonionic polymeric surfactants possess good surface criteria and biological activity and blending them with ZnO-NPs to obtain polymeric surfactant nanocomposites for enhancing their biological activity against Gram-positive bacteria (Bacillus subtilis and Staph. aureus), Gram-negative bacteria (P. aeruginosa and E. coli), yeast (Candida albicans) and microalga (Chlorella Vulgaris).

Co0.85Se nanoparticles armored by N-doped carbon layer with electronic structure regulation functions: An efficient oxygen evolution electrocatalyst

In this work, with the assistance of polymeric nonionic surfactant Pluronic F127, 2D nanosheets glycerol cobalt self-assembled into the ball-flower structure composites (CoG@F127). Then, CoG@F127 is coated by polydopamine (PDA) to form CoG@F127@PDA. After the calcination with Se powder, CoG@F127@PDA is transformed into the ball-flower hierarchical structure Co0.85Se-NC/C, in which Co0.85Se nanoparticles are coated with nitrogen doped carbon (NC). The Co0.85Se nanoparticles anchored on the NC can avoid the aggregation, maintain structure stability and expose more electrocatalytic active sites for oxygen evolution reaction (OER). Specially, Co0.85Se-NC/C-750 shows a small Tafel slope of 47.2 mV dec-1 in 1.0 M KOH that is even lower than IrO2 and most of the reported Co-based catalysts. Besides, the theoretical calculations by density functional theory (DFT) suggest that NC could tailor the electronic structure of Co0.85Se, leading to optimized free energy change (ΔG) of the speed-controlled step and density of states (DOS).

The adsorption of HEC and PVA as surfactants on SrTiO3 surface: A theoretical, experimental and applied investigation

Surfactants at solid/liquid interface could effectively improve the wettability of the liquid to the solid. Both the atomic force microscope (AFM) and theoretical calculations were applied to illustrate the mechanisms of behaviors of nonionic polymer surfactants represented by hydroxyethyl cellulose (HEC) and polyvinyl alcohol (PVA) at the solid/liquid interface of surfactant-assisted Pechini sol-gel method. The results clarified that the contact angles of surfactant-added sol reduced from64.92° ± 0.42° to 44.04° ± 0.37° and 48.53° ± 0.52° and the surfactants adsorbed on the solid in the form of disk shape, of diameter d = 500 nm and 100 nm for HEC and PVA, respectively. In addition, the adsorption energies between the oxygen atoms of the hydrophilic groups and the metal ion sites of the solid surface are -0.13 eV atom−1 for HEC and -0.04 eV atom−1 for PVA, respectively, indicating that the ion paring played a crucial role in improving the wettability of the sol to the solid. Furthermore, Bi-based superconductors with various morphologies could be prepared using surfactant-assisted Pechini sol-gel method with excellent crystallinity and transition temperatures of ∼70 K, exhibiting potential prospect in the preparation of functional oxide materials with different morphologies by wet-chemical technique.

Association between Nonionic Amphiphilic Polymer and Ionic Surfactant in Aqueous Solutions: Effect of Polymer Hydrophobicity and Micellization.

The interaction in aqueous solutions of surfactants with amphiphilic polymers can be more complex than the surfactant interactions with homopolymers. Interactions between the common ionic surfactant sodium dodecyl sulfate (SDS) and nonionic amphiphilic polymers of the poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO-PPO-PEO) type have been probed utilizing a variety of experimental techniques. The polymer amphiphiles studied here are Pluronic F127 (EO100PO65EO100) and Pluronic P123 (EO19PO69EO19), having the same length PPO block but different length PEO blocks and, accordingly, very different critical micellization concentrations (CMC). With increasing surfactant concentration in aqueous solutions of fixed polymer content, SDS interacts with unassociated PEO-PPO-PEO molecules to first form SDS-rich SDS/Pluronic assemblies and then free SDS micelles. SDS interacts with micellized PEO-PPO-PEO to form Pluronic-rich SDS/Pluronic assemblies, which upon further increase in surfactant concentration, break down and transition into SDS-rich SDS/Pluronic assemblies, followed by free SDS micelle formation. The SDS-rich SDS/Pluronic assemblies exhibit polyelectrolyte characteristics. The interactions and mode of association between nonionic macromolecular amphiphiles and short-chain ionic amphiphiles are affected by the polymer hydrophobicity and its concentration in the aqueous solution. For example, SDS binds to Pluronic F127 micelles at much lower concentrations (~0.01 mM) when compared to Pluronic P123 micelles (~1 mM). The critical association concentration (CAC) values of SDS in aqueous PEO-PPO-PEO solutions are much lower than CAC in aqueous PEO homopolymer solutions.

Effect of cationic, anionic and non-ionic polymeric surfactants on the stability, photo-catalytic and antimicrobial activities of yttrium oxide nanofluids

This work describes the utilization of combining the properties of yttrium oxide as a photoactive metal oxide and the properties of different kinds of charged surfactants: cationic, anionic and non-ionic polymeric types. The surface charge of surfactants was found to have a great influence on the stabilization performance of yttrium oxide particles in aqueous surfactant media, known as nanofluids, as well as on their photocatalytic and antimicrobial activities. Ionic surfactants (cetyltrimethylammonium bromide (CTAB) as a cationic surfactant and sodium dodecyl sulfate (SDS) as an anionic one) reduce the particle aggregation while the non-ionic polymeric surfactant (Polysorbate 80, Polyoxyethylene (20) sorbitan monooleate or (x)-sorbitan mono-9-octadecenoate poly(oxy-1,2-ethanediyl) (Tween 80)) enhanced the particles aggregation and formed a polymeric layer on the aggregates surface. The prepared nanofluids morphological structure and stability were studied by means of TEM, DLS and Zeta potential measurements. The prepared nanofluid systems were found to have an enhanced photo-catalytic performance for the degradation of MG dye studied under both UV and visible light irradiations and an enhanced wide spectrum antimicrobial activity against Gram positive and Gram negative bacteria as well as fungal stains.

Magnetic Polyurea Nano-Capsules Synthesized via Interfacial Polymerization in Inverse Nano-Emulsion.

Polyurea (PU) nano-capsules have received voluminous interest in various fields due to their biocompatibility, high mechanical properties, and surface functionality. By incorporating magnetic nanoparticle (MNPs) into the polyurea system, the attributes of both PU and MNPs can be combined. In this work, we describe a facile and quick method for preparing magnetic polyurea nano-capsules. Encapsulation of ionic liquid-modified magnetite nanoparticles (MNPs), with polyurea nano-capsules (PU NCs) having an average size of 5–20 nm was carried out through interfacial polycondensation between amine and isocyanate monomers in inverse nano-emulsion (water-in-oil). The desired magnetic PU NCs were obtained utilizing toluene and triple-distilled water as continuous and dispersed phases respectively, polymeric non-ionic surfactant cetyl polyethyleneglycol/polypropyleneglycol-10/1 dimethicone (ABIL EM 90), diethylenetriamine, ethylenediamine diphenylmethane-4,4′-diisocyanate, and various percentages of the ionic liquid-modified MNPs. High loading of the ionic liquid-modified MNPs up to 11 wt% with respect to the dispersed aqueous phase was encapsulated. The magnetic PU NCs were probed using various analytical instruments including electron microscopy, infrared spectroscopy, X-ray diffraction, and nuclear magnetic spectroscopy. This unequivocally manifested the successful synthesis of core-shell polyurea nano-capsules even without utilizing osmotic pressure agents, and confirmed the presence of high loading of MNPs in the core.

Preparation and characterization of porous iron oxide dendrites for photocatalytic application

In the present work, the role of the nonionic polymeric surfactant, pluronic P123 on the formation of porous iron oxide dendrite structures are explored. The iron oxide samples were prepared at different hydrothermal treatment time of 6, 12, 24 and 48 h using potassium ferricyanide as the raw material in presence and in absence of surfactant. The samples were characterized by XRD, FTIR, SEM, HRTEM, DRS, PL, BET-BJH and XPS analyses. The iron oxide dendrites prepared using surfactant by the hydrothermal treatment time of 12 h at 180 °C (PK12), show high photocatalytic degradation ability of 87 % towards methylene blue under visible light for a less amount of catalyst loading of 10 mg. Whereas the iron oxide prepared in absence of surfactant under similar conditions (K12) shows the incomplete phase formation with mixed dendrite and bulk cubic structures, exhibiting only 47 % of degradation towards methylene blue for the similar amount of catalyst loading. The sample PK12 exhibits a degradation rate constant value of 4.25 × 10−4 s−1 which was 2.3 times higher than the sample K12 with a rate constant value of 1.88 × 10−4 s−1. The enhanced catalytic performance of the sample PK12 prepared using surfactant are attributed to its bimodal porous nature, stronger visible light absorbance, and lower recombination of photo-generated electron-hole pairs. XPS results substantiates that significant oxygen vacancies in as prepared photocatalyst, facilitates the superior photocatalytic performance. The relative peak area ratio between Olattice/Ovac was found to be lower in PK12 (0.98) than in K12 (1.82). This indicates the sample PK12 have more oxygen vacancies than the sample K12. After the photocatalytic degradation, iron oxide was retrieved by simple sedimentation process and reused for four times without any considerable decrease in efficiency, proving its economic viability for large scale applications. Magnetic studies shows a coercivity of 1582 Oe and 1162 Oe for the samples PK12 and K12, respectively.