Anionic Surfactant Sodium Dodecyl Benzene Research Articles

Green Surfactant Assisted-Solidified Floating Organic Drop Micro-Extraction (SA-SFODME) for the Preconcentration of Trace Lead with Determination by Flame Atomic Absorption Spectrometry (FAAS)

Determination of trace lead from environmental samples was carried out by solidified floating organic drop microextraction for preconcentration before analysis by flame atomic absorption spectrometry. The determination of lead from environmental samples, even at trace levels, was possible with an ordinary flame atomic absorption spectrometer (FAAS). The lead formed a hydrophobic complex with the anionic surfactant sodium dodecyl benzene sulfonate (SDBS), and this hydrophobic complex was extracted into the 1-dodecanol drop. Parameters affecting analytical performance have been studied. The optimum pH value was 3.5. The optimum sample volume, SDBS concentration, and extraction solvent volume were 75 mL, 50 mM in dodecanol, and 75 µL, respectively. The optimum extraction time was determined as 30 min, the optimum extraction temperature was 45 °C, the optimum mixing speed was 650 rpm and the ideal extraction phase volume was 0.50 mL. Methanol has been shown to be effective when used as a diluent. Using the optimum conditions, the enhancement factor was 106, and the limit of detection (3s) and precision were 3.3 ng/mL and 2.3% (n = 9,15 ng/mL), respectively. The limit of quantification (LOQ) (10s) was 10 ng/mL and the linear working range was 15-100 ng/mL. The accuracy was evaluated by certified reference material analysis. The optimized method was applied to the determination of Pb(II) from environmental water samples. This method follows the principles of green analytical chemistry.

An Artificial Liquid–Liquid Phase Separation-Driven Silk Fibroin-Based Adhesive for Rapid Hemostasis and Wound Sealing

The powerful adhesion systems of marine organisms have inspired the development of artificial protein-based bioadhesives. However, achieving robust wet adhesion using artificial bioadhesives remains technically challenging because the key element of liquid–liquid phase separation (LLPS)-driven complex coacervation in natural adhesion systems is often ignored. In this study, mimicking the complex coacervation phenomenon of marine organisms, an artificial protein-based adhesive hydrogel (SFG hydrogel) was developed by adopting the LLPS-mediated coacervation of the natural protein silk fibroin (SF) and the anionic surfactant sodium dodecylbenzene sulfonate (SDBS). The assembled SF/SDBS complex coacervate enabled precise spatial positioning and easy self-adjustable deposition on irregular substrate surfaces, allowing for tight contact. Spontaneous liquid-to-solid maturation promoted the phase transition of the SF/SDBS complex coacervate to form the SFG hydrogel in situ, enhancing its bulk cohesiveness and interfacial adhesion. The formed SFG hydrogel exhibited intrinsic advantages as a new type of artificial protein-based adhesive, including good biocompatibility, robust wet adhesion, rapid blood-clotting capacity, and easy operation. In vitro and in vivo experiments demonstrated that the SFG hydrogel not only achieved instant and effective hemostatic sealing of tissue injuries but also promoted wound healing and tissue regeneration, thus advancing its clinical applications. Statement of significanceMarine mussels utilize the liquid–liquid phase separation (LLPS) strategy to induce the supramolecular assembly of mussel foot proteins, which plays a critical role in strong underwater adhesion of mussel foot proteins. Herein, an artificial protein-based adhesive hydrogel (named SFG hydrogel) was reported by adopting the LLPS-mediated coacervation of natural protein silk fibroin (SF) and anionic surfactant sodium dodecylbenzene sulfonate (SDBS). The assembled SFG hydrogel enabled the precise spatial positioning and easy self-adjustable deposition on substrate surfaces with irregularities, allowing tight interfacial adhesion and cohesiveness. The SFG hydrogel not only achieved instant and effective hemostatic sealing of tissue injuries but also promoted wound healing and tissue regeneration, exhibiting intrinsic advantages as a new type of artificial protein-based bioadhesives.

Adsorption-solubilization controlled extraction of pyrene from surfactant solutions by graphene oxide

Graphene and its derivatives such as graphene oxide (GO) has attracted increasing attention in water treatment because of its unique physical and chemical properties. Herein, the adsorption performance of GO for a typical polycyclic aromatic hydrocarbon (PAH), pyrene from solutions of either a non-ionic surfactant Tergitol 15-S-7 or an anionic surfactant sodium dodecyl benzene sulphonate (SDBS) is investigated. It demonstrates that the high affinity of GO to pyrene leads to multi-layer adsorption of pyrene, with an adsorption capacity 2 to 3 times of its own weight at a low GO concentration of 3.9 mg/L. Linear two-zone pyrene adsorption isotherms are identified, which should be due to competitive adsorption-solubilization processes of pyrene. Although Tergitol 15-S-7 has a considerably higher solubilization capacity (affinity) for pyrene compared to SDBS, faster adsorption kinetics, larger solid-liquid distribution coefficients, and higher recovery of pyrene from Tergitol 15-S-7 solutions are achieved. The higher affinity of SDBS to GO leads to its competitive adsorption that impairs the adsorption of pyrene by GO. Furthermore, the GO demonstrates excellent adsorption capacity for pyrene even after 5 recycling cycles.

Molecular dynamics models to investigate the diffusion behavior of emulsified asphalt

The utilization of emulsified asphalt is widespread in the recycling of asphalt pavement due to its eco-friendliness and energy efficiency. While numerous research studies have been conducted on the mixture design and strength assessment of emulsified asphalt, the mechanism by which it diffuses and adheres to the aggregate surface remains inadequately comprehended. This study developed molecular dynamics models to investigate the diffusion behavior of emulsified asphalt on the aggregate surface to clarify the role of emulsifier, water, and asphalt in the adsorption process from a molecular perspective. Interface models are established according to the diffusion state for interfacial adhesion evaluation. The results show that the movement of water molecules is the driving force for the entire emulsified asphalt to adsorb to the aggregate surface, whether the aggregate is silica or reclaimed asphalt pavement (RAP). Compared with anionic surfactant Sodium Dodecylbenzene Sulfonate (SDBS), cationic emulsifier Cetyltrimethylammonium Chloride (CTAC) has a better affinity, stronger adsorption, and higher interfacial adhesion energy with silica. Compared with RAP, emulsified asphalt is more readily adsorbed to the surface of silica. It is concluded that emulsifiers have two distribution conformations during the adsorption process, delamination, and aggregation, with delamination exhibiting stronger interface strength with silica than aggregation. When the emulsified asphalt spreads on the RAP surface, the penetration of water molecules into the aged asphalt layer in the RAP structure reduces the structure's water resistance. These results can provide a molecular perspective for understanding the internal structure of emulsified cold recycle mixture (ECRM) and link the adsorption behavior of emulsified asphalt on aggregate surfaces with the internal interface strength of ECRM.

The effect of anionic surfactant type and concentration on the development of waterborne nitrocellulose

To better understand the gel emulsification method as an efficient method for producing waterborne nitrocellulose coatings [1–3], the effect of anionic surfactant type (sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS)) and concentration on the emulsification process was investigated. In the case of using SDBS, it was not possible to produce nitrocellulose emulsion via the gel emulsification method while emulsions with submicron size were produced using SDS. Contrary to what might be thought, in the gel emulsification method, high surfactant concentrations did not contribute to better drop breakage and led to catastrophic phase inversion. In addition, increasing surfactant concentration increased the hydrophilicity of the final coatings and decreased their chemical and mechanical properties.

Molecular dynamics simulation of surfactant induced wettability alteration of shale reservoirs

Shale oil has recently received considerable attention as a promising energy source due to its substantial reserves. However, the recovery of shale oil presents numerous challenges due to the low-porosity and low-permeability characteristics of shale reservoirs. To tackle this challenge, the introduction of surfactants capable of modifying wettability has been employed to enhance shale oil recovery. In this study, we perform molecular dynamics simulations to investigate the influence of surfactants on the alteration of wettability in shale reservoirs. Firstly, surfaces of kaolinite, graphene, and kerogen are constructed to represent the inorganic and organic constituents of shale reservoirs. The impact and underlying mechanisms of two types of ionic surfactants, namely, the anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and cationic surfactant dodecyltrimethylammonium bromide (DTAB), on the wettability between oil droplets and surfaces are investigated. The wettability are analyzed from different aspects, including contact angle, centroid ordinates, and self-diffusion coefficient. Simulation results show that the presence of surfactants can modify the wetting characteristics of crude oil within shale reservoirs. Notably, a reversal of wettability has been observed for oil-wet kaolinite surfaces. As for kerogen surfaces, it is found that an optimal surfactant concentration exists, beyond which the further addition of surfactant may not enhance the efficiency of wettability alteration.

Complexes of an Anionic Surfactant with Chitosan and Its Hydrophobic Derivatives As Disinfectants against SARS-CoV-2

This work is aimed at the preparation of complexes of chitosan and hydrophobically modified (HM) chitosan with an anionic surfactant sodium dodecylbenzene sulfonate (SDBS), and at the study of the virucidal activity of the complexes and their components against SARS-CoV-2. It is shown that the introduction of a sufficient amount (4 mol%) of hydrophobic n-dodecyl side groups provides the activity of HM chitosan against SARS-CoV-2 at moderate concentrations, at which unmodified chitosan and chitosan containing a lower amount of hydrophobic groups do not show any activity. Complexes of HM chitosan with SDBS are prepared, which is proven by fluorescence spectroscopy and isothermal titration calorimetry. It is discovered that HM chitosan/SDBS complex is more active than the polymer without surfactant, and an increase of the amount of hydrophobic groups enhances the activity

A novel PVA/MWCNTs hydrogel with high toughness and electromagnetic shielding properties

AbstractCarbon nanotubes (CNTs) are widely utilized as conductive fillers due to their high conductivity, lightweight, and ease of modification. However, their poor dispersion limits their otherwise excellent performance. In this study, we successfully prepared a high toughness, strong electromagnetic interference (EMI) shielding hydrogel by blending polyvinyl alcohol (PVA) hydrogel with multi‐walled carbon nanotubes (MWCNTs) modified by anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and (3‐aminopropyl) triethoxysilane (KH550). We found that the modifiers can not only promote the uniform dispersion of MWCNTs but also improve the mechanical properties of the hydrogel. The results demonstrate that the stress (≈14.86 MPA), elongation at break (233.9%), and compressive strength (≈2.89 MPA) of PVA/MWCNTs composite hydrogel with 1 wt% MWCNTs and 5 wt% PVA were increased by 533.6%, 241.4%, and 206.5%, respectively. Encouragingly, the total electromagnetic shielding effectiveness (SET) is 123.6 dB at a thickness of 5 mm. In summary, this work provides a general approach to functionalizing MWCNTs, which has great potential for developing EMI shielding materials with high toughness.

Effects and mechanisms of different types of surfactants on sapphire ultrasonic polishing

The effects of three different types of surfactants, including cationic surfactant cetyltrimethylammonium bromide (CTAB), anionic surfactant sodium dodecyl benzene sulfonate (SDBS), and nonionic surfactant fatty alcohol polyoxyethylene ether (AEO), on sapphire ultrasonic polishing (UV-CMP) were studied. Through XPS, SEM, surface tension, zeta potential and particle size analysis, the implications of surfactants on the chemical products, abrasive adsorption, and material removal rate (MRR) of sapphire surface were investigated. The findings indicate that AEO and SDBS result in a certain degree of abrasive agglomeration and slight particle size increase due to hydrogen bonding and electrostatic repulsion respectively. The cationic surfactant CTAB exhibits significant agglomeration of abrasive particles due to electrostatic attraction, and causes the increase in particle size. The slurry’s surface tension is directly proportional to sapphire MRR within a certain range. The polishing effects are the best when 0.10% CTAB is added. Sapphire MRR is 80.50 nm/min, which is nearly twice as much as that of the slurry without surfactants. The surface roughness is 0.200 nm after polishing.

SDBS-Induced Dispersion Effect of High-Rank Coal Fines to Inhibit the Conductivity of Propping Fractures

Coal fines are commonly produced in the form of aggregates during the development of coalbed methane (CBM), which significantly restricts the well productivity. Specifically, the reunion state of coal fines plays a key role in impacting the conductivity of propping fractures after fracturing. In this work, the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) was selected to control the reunion state of coal fines. Visualized simulations of coal fines’ transport behavior in proppants with different particle sizes were carried out under low constant pressure based on sand pack experiments. Moreover, the characteristics of coal fine filling and production in propping fractures were obtained. The results indicate that SDBS has a dispersion effect on coal fine aggregates in the KCl fracturing fluid, with an average reduction of 36% in particle size. There is a positive correlation between the proppant size and the permeability coefficient of propping fractures. Coal fines reduce the permeability coefficients obviously, which first rapidly decrease and then slowly reach a stable stage. In the first stage, the changes of permeability coefficients are affected by the relative particle sizes of the proppant and the coal fine, which is consistent with the classic 1/3 sealing mechanism. In the second stage, SDBS increases the amount of coal fines between the proppant pore throats, and the thickness of the filter cake formed from coal fines at the entrance of the propping fracture increases, resulting in the inhibition of fracture conductivity. Additionally, the output of coal fines is increased dramatically induced by SDBS. Finally, the inhibitory effect of SDBS on fluid production was verified by comparing the water production and coal fine content of two field wells CW # 1 and CW # 2. This study has guiding significance for the output and control of coal fines in low-pressure production of CBM wells.

Gelation properties of amino-acid-based bis-urea compounds in organic solvents and in the presence of surfactants

ABSTRACT Self-assembled systems based on low-molecular-weight gelators (LMWGs) and micelle-forming surfactants are stabilized by non-covalent and non-interfering interactions. The simultaneous self-assembly of LMWGs and surfactants in a solution could lead to the formation of fibrillar networks with encapsulated surfactant micelles. In this study, the gelation properties of amino-acid-derived low-molecular-weight bis-urea compounds in water, various organic solvents, and surfactant solutions, including anionic surfactants sodium dodecyl sulfate and dodecylbenzene sulfonic acid, cationic surfactant cetrimonium bromide, and nonionic surfactants polysorbate 80 and octyl-β-d-glucopyranoside, were investigated. In the presence of surfactants, the nature of the linker of the bis-urea compounds influences the aggregation between gelator molecules. Compounds with cyclic and aromatic linkers effectively form gels at surfactant concentrations above a critical micelle concentration (CMC). The different fiber morphologies observed for surfactant gels based on imaging analysis suggest that the structure of the bis-urea compounds influences self-assembly. Rheological measurements revealed the solid-like nature of the gels and their high thermal stability. The viscoelastic nature of the surfactant gels offers potential use in various commercial applications, including home care products.

Designing an Efficient Surfactant–Polymer–Oil–Electrolyte System: A Multi-Objective Optimization Study

This research aimed to study the effects of individual components on the physicochemical properties of systems composed of surfactants, polymers, oils, and electrolytes in order to maximize the recovery efficiency of kerosene while minimizing the impact on the environment and human health. Four independent factors, namely anionic surfactant sodium dodecylbenzene sulfonate (X1) (SDBS), oil (X2) (kerosene), water-soluble polymer poly(ethylene glycol) (X3) (PEG), and sodium chloride (X4) (NaCl), were studied using the full factorial design (FFD) model. Four output variables, namely conductivity (Y1), turbidity (Y2), viscosity (Y3), and interfacial tension (IFT) (Y4), were taken as the response variables. All four FFD models have high coefficients of determination and low errors. The developed models were used in a multi-objective optimization (MOO) framework to determine the optimal conditions. The obtained optimal conditions are X1 = 0.01, X2 = 50, X3 = 5, and X4 = 0.1, with an error of 0.9414 between the predicted and experimental objective function values. This result shows the efficiency of the model developed and the system used for the recovery of kerosene, while also having a positive effect on the protection of the environment.

Impact of carbonate mineral heterogeneity on wettability alteration potential of surfactants

Surfactants have been widely used for enhanced oil recovery. However, the wettability alteration potential of surfactants as a function of carbonate rock mineralogy remains broadly unclear. Thus, here we investigate the effect of cationic surfactant cetyltrimethylammonium ammonium bromide (CTAB) and anionic surfactant sodium dodecyl benzene sulphonate (SDBS) surfactant on three carbonate rocks and a pure calcite mineral sample under a range of concentrations. Contact angles were measured on all these samples as a function of surfactant concentration. Furthermore, at the critical micelle concentration, advancing and receding contact angles are also measured as a function of pressure (0.1 – 20 MPa) and temperature (303 – 323 K) to reflect the behavior under subsurface conditions. To understand the interactions at the surfactant-mineral interface and its associated impact on wettability alteration, the zeta potential of surfactant-brine-rock emulsions are measured while surface chemical groups are identified by Fourier-transform infrared (FTIR) spectroscopy. The results are further supplemented by Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction analysis (XRD), and thin section analysis while the surface properties are evaluated by Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) techniques. The results indicate a notable wettability alteration potential for CTAB turning the calcite surface water-wet while increasing the surfactant concentration did not necessarily yield better wettability alteration. The wettability alteration potential of CTAB is found to correlate with the calcite content of the carbonate sample i.e., a higher calcite content led to a greater reduction in contact angle. Contact angles demonstrate a slight increase with increasing pressure, while they decreased with increasing temperature. Finally, the existence of CO group (carboxylate groups) tends to make the CTAB-treated surface more hydrophilic while the surfaces treated with SDBS did not reveal any notable trend with respect to CO group. The results of this study add to our understanding of the surfactant potential for wettability alteration of carbonate and thus have implications for chemical enhanced oil recovery.

Study the Effect of Phenol on formation of Supramolecular gel

In this work, the cationic surfactant hexacetyl pridinium chloride (HCPC) was blended with anionic surfactant Sodium Dodecyl benzene Sulfate (SDBS) by using different concentrations (0.0025 - 0.1M) of phenol and at temperature ranges (20-35 Co). It was found that the viscosity values for the mixture of SDBS / HCPC at a certain mixing ratios (12/3, 10.5/4.5 and 9/6), were increased in the presence of phenol, due to formation of self-assembled supramolecular. Moreover, the thermodynamic functions as well as the activation energy for the process of self-assembled were calculated. Conductivity measurements were also performed for further support. The results revealed a physical interaction insight intermolecular forces.

A Robust Switchable Oil-In-Water Emulsion Stabilized by Electrostatic Repulsions between Surfactant and Similarly Charged Carbon Dots.

How to control the stability of oil-in-water (O/W) emulsions is one of the main topics for scientists working in colloidal systems. Recently, carbon dots (CDs) have received great interest as smart materials because of their excellent physicochemical properties and versatile applications. Herein, for the first time, advanced and switchable O/W emulsions are presented that are stabilized by the synergistic effect of cationic surfactant cetyltrimethylammonium bromide CTAB (emulsifier) and similarly charged CDs (stabilizer). In the formulated emulsion, the cationic surfactant molecules are adsorbed at the oil and water interface to decrease the interfacial tension and enrich the drops with a positive charge to ensure intensive electrostatic repulsions among them. On the contrary, cationic CDs are distributed in the water phase among the droplets to reduce the water secretion and prevent flocculation and droplet coalescence. The stabilizing effect is found to be universal for emulsions of a range of oil phases. Furthermore, the formulated emulsion is found to be switchable between "stable" and "unstable" modes by adding an equivalent of anionic surfactant sodium dodecyl benzene sulphonate (SDBS). The stabilized and switchable O/W emulsions are believed to have wide practical applications in water purification, pharmaceuticals, protein recognition, as well as catalysis.

Solar light-responsive Ag/CdS/TNTs (TiO2 nanotubes) photocatalysts for enhanced CO2 photoreduction and hydrogen evolution

The prepared ternary Ag/CdS/TNTs S-scheme heterojunction has superior morphology and enhanced photocatalytic performance. Under solar light, the yield of photocatalytic CO 2 to CO by Ag/CdS/TNTs nanocomposites was 1455.6 μmol‧g -1 ‧h -1 and the H 2 evolution rate by the nanocomposites was 3700.57 μmol‧g -1 ‧h -1 , which were much better than pure materials. • The in situ one-time synthesis of Ag/CdS/TNTs (TiO 2 nanotubes) S-scheme heterojunction with the help of anionic surfactant sodium dodecyl benzene sulfonate (SDBS) was simple and convenient. • The yield of photocatalytic CO 2 to CO by Ag/CdS/TNTs nanocomposites was 1455.6 μmol‧g -1 ‧h -1 , which was 1.5 times by pure CdS NPs. • It was found that Ag/CdS/TNTs nanocomposites displayed the H 2 evolution rate of 3700.57 μmol‧g -1 ‧h -1 , which was twice pure TiO 2 NPs. Solar-to-chemical energy conversion via heterogeneous photocatalysis is one of the effective approaches to tackle the growing environmental and energy challenges. Homogeneously dispersed silver nanoparticles (Ag NPs) and cadmium sulfide nanoparticles (CdS NPs) with average particle size not more than 20 nm were fabricated on the surface of titanium dioxide nanotubes (TNTs) (Ag/CdS/TNTs) with the help of sodium dodecyl benzene sulfonate (SDBS). Herein, more surface active sites are created on the surface of nanocomposites. The experimental results demonstrate that the photocurrent intensity of the nanocomposites obviously increased, which effectively improves the photocatalytic activity. The results of photocatalytic experiments indicated that using triethanolamine (TEOA) and acetonitrile (MeCN) as sacrificial agents, the nanocomposites afford the CO yield from CO 2 (1455.6 μmol‧g −1 ‧h −1 ). Besides, Ag/CdS/TNTs nanocomposites displayed the H 2 evolution rate of 3700.57 μmol‧g -1 ‧h -1 , which was twice as much as pure TiO 2 NPs. The increase in the photocatalytic ability of the nanocomposites is basically attributed to the three materials formation S-scheme heterojunction which reduce the recombination probability of the photo-induced electrons and holes and thus enhances the photocatalytic activitys. Ultimately, a photocatalytic reaction mechanism is proposed for Ag/CdS/TNTs nanocomposites in the reduction of CO 2 .

A sensitive photoluminescent sensor based on highly charged monoruthenium(II) complexes for dopamine detection

A sensitive and selective photoluminescent sensor based on the highly charged monoruthenium(II) complex was designed to detect dopamine (DA) in aqueous samples. Two novel highly charged cationic ruthenium(II) complexes [Ru(bpy)2(bpy-N)]X4 (bpy = 2,2′-bipyridine, bpy-N = 4,4′-bis[N,N,N-triethyl-(methylamino)]-2,2′-bipyridine, X− = [PF6]− (1a) or Cl− (1b) and [Ru(bpy)(bpy-N)2]X6 (X− = [PF6]− (2a) or Cl−(2b)) can be assembled with anionic surfactant sodium dodecylbenzene sulfonate (SDBS), leading to an enhancement of photoluminescence intensity. Upon addition of DA to the system, the photoluminescence intensity of the assembled system was quenched due to the energy transfer effect. It exhibited a wide linear range (0.1–50 μM) and low detection limit (10 nM). The sensor demonstrated a high selectivity toward DA, especially in the presence of adrenaline (Adr) and norepinephrine (NE), whose structures are similar to DA in biological systems. With the merits of simple operation, obvious phenomenon and fast response speed, the sensor had a potential application prospect in human urine sample.

Preparation and characterization of self-crosslinking acrylic emulsion with different fluorocarbon chain lengths

PurposeFluorine materials have received the keen attention of many researchers because of their water repellency and low surface free energy. The purpose of this paper is to prepare self-crosslinking fluorocarbon polyacrylate latexes containing different fluorocarbon chain lengths by semi-continuous seeded emulsion polymerization technology.Design/methodology/approachMethyl methacrylate (MMA), butyl acrylate (BA), hydroxypropyl methacrylate (HPMA) and fluorine-containing monomers were used as main monomers. The fluorine-containing monomers included hexafluorobutyl methacrylate (HFMA), dodecafluoroheptyl methacrylate (DFMA) and trifluorooctyl methacrylate (TFMA). Potassium persulfate (KPS) was used as thermal decomposition initiator, non-ionic surfactant alkyl alcohol polyoxyethylene (25) ether (DNS-2500) and anionic surfactant sodium dodecylbenzene sulfonate (SDBS) as mixed emulsifier.FindingsThrough optimizing the reaction conditions, the uniform and stable latex is gained. The polymer of structure was characterized by Fourier transform infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA) were tested on latex films. The particle size and distribution range of emulsion were tested with nano particle size analyzer. After comprehensively comparing the latexes and films prepared by HFMA, DFMA and TFMA, the performance of DFMA monomer modified is better.Originality/valueThe self-crosslinking acrylic emulsion is prepared via semi-continuous seeded emulsion polymerization, which methyl methacrylate (MMA), butyl acrylate (BA), hydroxypropyl methacrylate (HPMA) and fluorine-containing monomers were used as main monomers. The fluorine-containing monomers were composed of hexafluorobutyl methacrylate (HFMA), dodecafluoroheptyl methacrylate (DFMA) and trifluorooctyl methacrylate (TFMA). Potassium persulfate (KPS) was used as thermal decomposition initiator, non-ionic surfactant alkyl alcohol polyoxyethylene (25) ether (DNS-2500) and anionic surfactant sodium dodecylbenzene sulfonate (SDBS) as mixed emulsifier. There are two main innovations. One is that the self-crosslinking acrylic emulsion is prepared successfully. The other is that the effects of monomers containing different fluorocarbon chain lengths on polyacrylate, such as monomer conversion rate, coagulation rate, mechanical stability, chemical stability, emulsion particle size and storage stability, are studied in detail.

Experimental Study on the Wettability of Coal with Different Metamorphism Treated by Surfactants for Coal Dust Control.

Wet dedusting is the main coal dust suppression technique in coal mines, and coal wettability is the main factor affecting dust suppression efficiency. To investigate the main factors affecting the coal wettability and improve it, the coal–water contact angle was used as an index to characterize the coal wettability, and the wettability of six coal samples with different metamorphic degree was studied by analyzing the relationship between the physicochemical properties and the contact angle. To improve the coal wettability, the nonionic surfactant alkyl polyglycoside (APG), anionic surfactant sodium dodecyl benzene sulfonate (SDBS), and polymer surfactant polyacrylamide (PAM) were applied to the coal samples. The results show that SDBS is the most effective surfactant to improve the coal wettability, followed by APG, while the application of PAM would lead to more hydrophobic coal. It is also found that the coal wettability shows a high–low–high trend with the increase in the metamorphic degree. The wettability of long flame coal is the strongest and that of gas coal is the weakest. Moisture is the main hydrophilic factor of coal, while 1,4-dimethylbenzene is the main hydrophobic factor. The main factors affecting the treatment effect of APG, SDBS, and PAM on wettability are the aromatic methylbenzene, hydroxyl, and hydroxyl content of coal, respectively. Therefore, according to the content of hydroxyl in different coals, an SDBS solution can be prepared to improve the coal wettability. For coal with a low hydroxyl content, a higher concentration SDBS solution could be needed.

Light absorption and hydrophobicity of a polystyrene/multiwall carbon nanotube composite with surface nanostructures

This paper describes an investigation into how combined carbon nanotube doping and surface nanostructuring affects the surface properties of polystyrene. Multiwall carbon nanotubes (MWCNTs) have unique anisotropic electrical properties that can be utilized for light absorption, electromagnetic shielding and nanoscale electostatic forces. Polystyrene was doped with 5 wt% MWCNTs and the resulting composite was wetted onto a porous anodic alumina template to form a nanostructure surface of nanotubes. Scanning electron microscopy revealed a hierarchical surface structure with the composite nanotubes bundled together as the MWCNTs increased the attractive forces between the composite nanotubes. Water droplet testing revealed that this hierarchical surface structure was superhydrophobic. Though the presence of the MWCNTs caused a direct increase in absorption, the hierarchical surface structure increased reflection. The addition of 5 wt% of the anionic surfactant Sodium Dodecyl Benzene Sulfonate to ensure MWCNT dispersal did not significantly change hydrophobicity or light absorption despite the hierarchical surface structure becoming finer. The created composite has potential use as a surface layer on an organic surface cell as it provides reduced cleaning needs and electrical disturbance but further work is required to reduce the reflection.