Addition Of Nonionic Surfactant Research Articles

Roles of Nonionic Surfactant Additives in PEDOT:PSS Thin Films

The effects of nonionic surfactant additive, Triton X-100, on the properties of PEDOT:PSS thin films has been investigated. The detailed mechanism for the well-known conductivity enhancement upon the addition of high boiling point nonionic surfactant has been elucidated based on various characterization results. The surfactant additive has been found to enhance the π–π stacking of PEDOT segment, leading to enhanced electrical conductivity. In addition, the added surfactant has facilitated the removal of insulating PSS during the methanol spin washing, which contributes to further enhancement in electrical conductivity. Interestingly, the remaining surfactant in the dried PEDOT:PSS thin films plays the role of plasticizer. Upon aging of the films under room ambient (RH ∼ 30%), the conductivity of the film has been gradually increased until the humidity effect comes in. As a plasticizer, the surfactant has been found to enhance lamella stacking during the aging. Also, the mechanical modulus of the films has...

ВПЛИВ КОЕФІЦІЄНТА ПОВЕРХНЕВОГО НАТЯГУ РІДКОГО ТЕПЛОНОСІЯ НА СЕРЕДНЮ ТОВЩИНУ ПРИГРАНИЧНОГО ЛАМІНАРНОГО ШАРУ В РЕКУПЕРАТИВНИХ ТЕПЛООБМІННИКАХ

В процесах теплообміну визначальними є гідромеханічні характеристики потоків теплоносіїв, а саме їхні режими руху. В рекуперативних теплообмінниках загальний тепловий опір системи на 95% концентрується в пристінній області потоків теплоносіїв – в ламінарному при поверхневому шарі (ЛПШ). В існуючих рівняннях для розрахунку середніх товщин ЛПШ не враховуються поверхневі характеристики рідкофазних теплоносіїв (коефіцієнта поверхневого натягу та гідрофільності поверхні змочування). Зроблено силовий аналіз елементарного об’єму рідини в ЛПШ і встановлено пріоритетну дію сил поверхневого натягу та сил тиску. Виведена формула для розрахунку середньої товщини ЛПШ з врахуванням цих сил та коефіцієнта турбулізації КТ та співвідношення Дарсі–Вейсбаха. Одержана формула містить коефіцієнти поверхневого натягу, динамічної в’язкості та густину рідкого теплоносія, гідрофільність поверхні змочування внутрішньої рекуперативної стінки, довжину та діаметр труб, числа Рейнольдса та Дарсі, коефіцієнт турбулізації потоку.
 Запропоновано зменшувати середню товщину ЛПШ шляхом додавання до потоків теплоносіїв оптимальних концентрацій поверхнево–активних речовин (ПАР). Показано, що за додавання оптимальних концентрацій аніонактивних, неіоногенних та катіонактивних ПАР середня товщина ЛПШ зменшується в межах до 30%.

A preferential precursor for photocatalytically active titanium dioxide thin films: Titanium bis-ammonium lactato dihydroxide as an alternative to titanium tetra iso-propoxide

Titanium bis-ammonium lactato dihydroxide (TiBALD) precursor is used in place of the traditional sol–gel precursor, titanium tetra-isopropoxide (TTIP), to determine which precursor produces the most photocatalytically active titanium dioxide thin films. Films were deposited on glass substrates using modified sol–gel routes and the effects of non-ionic surfactant addition with Brij 58 and Brij 98 investigated. The morphology and nanostructure of the films have been assessed using SEM, XRD and Raman spectroscopy. The photocatalytic performance of the films was assessed using resazurin dye, whereby TiBALD precursor was found to produce thin films with enhanced photocatalytic efficiency, with an average rate of degradation for resazurin dye of 9.52×1012of dye molecules reduced per cm−2s−1 compared to 1.76×1012 dye molecules reduced per cm−2s−1 as for TTIP prepared films. A smaller average particle size (10–25nm) was also observed for thin films produced with TiBALD precursor, opening up potential for this precursor to be used for applications where a small TiO2 particle size is required. An overview of the differences between the two precursors for sol–gel deposition of TiO2 thin films is given within this study, including a discussion into the proposed differing decomposition mechanisms that may occur during sol–gel preparation.

Improvements in permeation and fouling resistance of PVC ultrafiltration membranes via addition of Tetronic-1107 and Triton X-100 as two non-ionic and hydrophilic surfactants.

Two non-ionic and hydrophilic surfactant additives, Tetronic-1107 and Triton X-100, were added to poly(vinyl chloride)/NMP polymeric solution to prepare ultrafiltration membranes via immersion precipitation. Surfactants at three different weight percentages up to 6 wt% were added, and the fabricated membranes were characterized and their performance for water treatment in the presence of bovine serum albumin (BSA) as a foulant was assessed. The scanning electron microscopy images indicated remarkable changes in morphology due to higher thermodynamic instability after surfactant addition. The membranes are more porous with more macro-voids in the sub-layer. Plus, the membranes become more hydrophilic. Water flux increases for the modified membranes by nearly two times and the ability of membranes for flux recovery increases from 66% to over 83%. BSA rejection reduces slightly with the addition of surfactants, however this parameter is still almost over 90% for the membranes with the highest amount of surfactants.

Assisted Bioremediation Approaches - Biostimulation and Bioaugmentation - Used in the Removal of Organochlorinated Pollutants from the Contaminated Bottom Sediments

The prospects of using the biostimulation and bioaugmentation treatment for the removal of the polychlorinated biphenyl (PCBs) from contaminated sediment collected from the sewage canal in the surroundings of a former PCB manufacturing plant in Slovakia is described. The eleven bacterial strains isolated in our previous work from sewage Stražsky canal sediments were able to aerobically degrade significant amounts of PCBs. Five of the bacterial isolates obtained were used in bioaugmentation treatment individually as single strains and within the eight artificially prepared consortia consisting of two or three strains. Bioaugmentation by a single strain was performed in other set of experiments combined with the addition of nonionic surfactants (Triton X and Tween 80) to increase bioavailability of PCBs and with the addition of terpenes (carvone and limonene) to induce required enzymes. The highest biodegradation of PCBs in biostimulation treatment was obtained using all three studied factors – addition of nitrogen, phosphorus, and oxygen to the indigenous microorganisms naturally present in the contaminated sediment. The highest biodegradation of PCBs in bioaugmentation experiments was obtained with the individual bacterial isolates (one Gram-positive and one Gram-negative), and with a laboratory prepared consortium consisting of three selected bacterial isolates. Addition of surfactant Tween 80 led to a higher biodegradation of PCBs than that of Triton X. Bioaugmentation treatment using the addition of single bacterial isolate and surfactant Tween 80 improved elimination of the evaluated indicator PCB congeners to the highest extent and thus appeared to be the most perspective technique for possible field bioremediation.

Novel amorphous mesoporous 0.25Cr2O3–0.75ZrO2 nanomaterials synthesized by a surfactant-assisted hydrothermal method for ethanol oxidation

Novel mesoporous 0.25Cr2O3–0.75ZrO2 nanomaterials were successfully synthesized via hydrothermal method in the presence of anionic, cationic and non-ionic surfactants, namely, SDS, CTAB and Triton X-100, respectively. The effect of different surfactants and their concentrations on the physicochemical properties and the catalytic activity of the catalysts were studied by the XRD, HR-TEM, FT-IR, BET, UV–vis/DR, NH3-TPD and ethanol oxidation techniques. XRD results indicated that all the as-prepared nanomaterials were amorphous materials. The morphology study demonstrated that the sample with CTAB has the smallest particle size while that with SDS has the largest value. The catalysts prepared with non-ionic and cationic surfactants have the highest surface area and the pore volume while those prepared with anionic or without surfactant have the smallest values. Additionally, the surface area of the catalysts decreases with increasing the surfactant content. The optical study indicated that the absorption peak of the nanomaterials shifts towards the short wavelength by changing the various surfactants. It is well-observed by NH3-TPD that the non-ionic and cationic surfactants enhanced the amount of acidic sites on the catalyst surface. These results indicate that the catalytic activity of mesoporous catalysts can be improved effectively by the addition of non-ionic and cationic surfactants.

Surfactant stabilisation of colloidal lignin microparticulates produced through a solvent attrition process

Abstract The stabilisation of insoluble lignin microparticulates produced through solvent attrition in aqueous media containing surfactants has been investigated. In the absence of added surfactants, addition of solvent solubilised lignin to water caused extensive precipitation and annealing of lignin, leading to the formation of large, agglomerated structures in the approximate size range of 20–200 μm. Addition of high HLB non-ionic surfactants (Polysorbate 20/sucrose ester) to the aqueous solution prior to lignin precipitation had only limited effect on the size of agglomerates produced, with a partial decrease in mean aggregate size at elevated surfactant concentrations, and no observed effect at low surfactant concentrations. In contrast, addition of either negatively (SDS) or positively (CTAB) charged ionic surfactants at concentrations Findings indicate that adsorption of charged surfactants to the surface of lignin particles during precipitation is able to provide effective electrostatic stabilisation; however, no such stabilising effect is provided by non-ionic surfactants. Furthermore, it appears that the size and stability of the particles produced is dependent on the conditions within the aqueous phase during precipitation. In this way, it may be possible to produce lignin microparticles with tailored particle distributions.

Performance and Efficiency of Anionic Dishwashing Liquids with Amphoteric and Nonionic Surfactants

AbstractPerformance and efficiency of anionic [sodium lauryl ether sulfate (SLES) and sodium α‐olefin sulfonate (AOS)] and amphoteric [cocamidopropyl betaine (CAB)] as well as nonionic [cocodiethanol amide (DEA), various ethoxylated alcohols (C12–C15–7EO, C10–7EO and C9–C11–7EO) and lauramine oxide (AO)] surfactants in various dishwashing liquid mixed micelle systems have been studied at different temperatures (17.0, 23.0 and 42.0 °C). The investigated parameters were critical micelle concentration (CMC), surface tension (γ), cleaning performance and, foaming, biodegradability and irritability of anionic (SLES/AOS) and anionic/amphoteric/nonionic (SLES/AOS/CAB/AO) as well as anionic/nonionic (SLES/AOS/DEA/AO, SLES/AOS/C12‐C15‐7EO/AO, SLES/AOS/C10–7EO/AO and SLES/AOS/C9–C11–7EO/AO) dishwashing surfactant mixtures. In comparison to the starting binary SLES/AOS surfactant mixture, addition of various nonionic surfactants promoted CMC and γ lowering, enhanced cleaning performance and foaming, but did not significantly affect biodegradability and irritability of dishwashing formulations. The anionic/nonionic formulation SLES/AOS/C9–C11–7EO/AO shows both the lowest CMC and γ as well as the best cleaning performance, compared to the other examined dishwashing formulations. However, the results in this study reveal that synergistic behavior of anionic/nonionic SLES/AOS/ethoxylated alcohols/AO formulations significantly improves dishwashing performance and efficiency at both low and regular dishwashing temperatures (17.0 and 42.0 °C) and lead to better application properties.

Optimization of Water-based Drilling Fluid Using Non-ionic and Anionic Surfactant Additives

Drilling fluid with better rheological and filtration properties control are required to optimise the performance of oil well drilling. In this study, a non-ionic and anionic surfactant was used as an additive in water-based drilling fluid to optimize their rheological and filtration properties. The rheology of water-based drilling fluid was taken after being hot rolled for 16hours at 250oF and 275oF, while the filtration tests were conducted at temperatures up to 300oF. It was found that non-ionic and anionic surfactant in water-based drilling fluid improved rheological and filtration properties. Moreover, surfactant additives are 41.3% more effective in reducing the filtration loss compared to the mud without surfactants. The long chain of non-ionic and ionic surfactant might result in a more viscous fluid, blocking the pores and forming a tight filter cake. The surfactants also caused water-based drilling fluids become more resistant at the higher temperature as shown by improved and stabilised the rheology and filtration properties after the hot aging process.

非イオン性界面活性剤と光反応性添加剤から構成されるフォトレオロジー流体の抵抗低減効果

非イオン性界面活性剤と光反応性添加剤から構成されるフォトレオロジー流体の抵抗低減効果

Interactions between Cellulolytic Enzymes with Native, Autohydrolysis, and Technical Lignins and the Effect of a Polysorbate Amphiphile in Reducing Nonproductive Binding.

Understanding enzyme-substrate interactions is critical in designing strategies for bioconversion of lignocellulosic biomass. In this study we monitored molecular events, in situ and in real time, including the adsorption and desorption of cellulolytic enzymes on lignins and cellulose, by using quartz crystal microgravimetry and surface plasmon resonance. The effect of a nonionic surface active molecule was also elucidated. Three lignin substrates relevant to the sugar platform in biorefinery efforts were considered, namely, hardwood autohydrolysis cellulolytic (HWAH), hardwood native cellulolytic (MPCEL), and nonwood native cellulolytic (WSCEL) lignin. In addition, Kraft lignins derived from softwoods (SWK) and hardwoods (HWK) were used as references. The results indicated a high affinity between the lignins with both, monocomponent and multicomponent enzymes. More importantly, the addition of nonionic surfactants at concentrations above their critical micelle concentration reduced remarkably (by over 90%) the nonproductive interactions between the cellulolytic enzymes and the lignins. This effect was hypothesized to be a consequence of the balance of hydrophobic and hydrogen bonding interactions. Moreover, the reduction of surface roughness and increased wettability of lignin surfaces upon surfactant treatment contributed to a lower affinity with the enzymes. Conformational changes of cellulases were observed upon their adsorption on lignin carrying preadsorbed surfactant. Weak electrostatic interactions were determined in aqueous media at pH between 4.8 and 5.5 for the native cellulolytic lignins (MPCEL and WSCEL), whereby a ∼20% reduction in the enzyme affinity was observed. This was mainly explained by electrostatic interactions (osmotic pressure effects) between charged lignins and cellulases. Noteworthy, adsorption of nonionic surfactants onto cellulose, in the form cellulose nanofibrils, did not affect its hydrolytic conversion. Overall, our results highlight the benefit of nonionic surfactant pretreatment to reduce nonproductive enzyme binding while maintaining the reactivity of the cellulosic substrate.

Kinetics for diclofenac degradation by chlorine dioxide in aqueous media: Influences of natural organic matter additives

The kinetics involved with the oxidation of diclofenac (DCF) by chlorine dioxide was investigated in the absence, and presence, of natural organic matter additives. Under the study conditions, we demonstrated that DCF may be rapidly and completely oxidized by excess ClO2. The observed pseudo first-order rate constant (kobs) increased linearly with ClO2 concentration. Addition of cationic (CTAB), anionic (SDBS), and non-ionic (Tween-80) surfactants as additives conveyed significant influences on the kinetic properties of the DCF-ClO2 reaction. Primarily, surface promotion was observed in low concentrations of CTAB through the adsorption of the reacting species on micellar surfaces, as both reactants were ionic, while this rate enhancement was suppressed in high concentrations of CTAB. Instead, inhibitory effects were observed on the samples that had been added SDBS, Tween-80 or humic acid with it being most effective, which confirmed the environmental relevance of the observed interactions between DCF and natural organic constituents.

Gelation of a Monoclonal Antibody at the Silicone Oil–Water Interface and Subsequent Rupture of the Interfacial Gel Results in Aggregation and Particle Formation

The formation of viscoelastic gels by a monoclonal antibody (mAb) at the silicone oil-water interface was studied using interfacial shear rheology. At a concentration of 50 μg/mL, the mAb formed gels in less than 1 h, and the gelation time decreased with increasing protein concentration. To probe the effects of mechanical rupture of the interfacial gel layers, a layer of silicone oil was overlaid on the surface of aqueous solutions of mAb, and the interface was ruptured periodically with a needle. Rupture of the interfacial gel resulted in formation of subvisible particles and substantial losses of mAb monomer, which were detected by microflow imaging and quantified by size-exclusion chromatography, respectively. Resonance mass measurement showed that levels of both protein particles and silicone oil droplets increased as the gel was repeatedly ruptured with a needle. In contrast, in samples wherein the interfacial gels were not ruptured, much lower levels of aggregates and particles were detected. Addition of nonionic surfactants (polysorbate 20 or polysorbate 80) protected against aggregation and protein particle formation, with increased protection seen with increasing surfactant levels, and with the greatest inhibition observed in samples containing polysorbate 80.

Insight into the Interaction Between Carbopol® 940 and Ionic/Nonionic Surfactant

AbstractMixtures of a cross‐linked polyacrylic acid (Carbopol® 940) and two types of surfactants, namely anionic sodium dodecylsulfate (SDS) and nonionic Tween® 80, were investigated by viscometry, conductometry, tensiometry, spectrophotometry, fluorimetry and scanning electron microscopy (SEM). The addition of nonionic surfactant decreased the reduced viscosity and the transmittance of the Carbopol® polymer aqueous solutions. Furthermore, the interaction between Carbopol® 940 and SDS was characterized by two significant concentration values: the critical aggregation concentration of SDS was particularly independent of Carbopol® polymer concentration while the polymer saturation point of both surfactants increased with the increase in polymer content. The values of critical aggregation concentration and polymer saturation point obtained using various techniques confirmed the occurrence of Carbopol® polymer–surfactant associations. The effect of different SDS and Tween® 80 concentrations on the conformation of Carbopol® 940 in aqueous solution could be explained through hydrophobic association between surfactant micelles and Carbopol® polymer tails and through hydrogen bonding in the case of Tween® 80. Additionally, the surfactant‐induced structural changes were confirmed in Carbopol® 940–SDS and Carbopol® 940–Tween® 80 aqueous solutions by SEM measurements.

Treatment of acetamiprid insecticide from artificially contaminated water by colloidal manganese dioxide in the absence and presence of surfactants

Acetamiprid is one of the most important pesticides and is effective against a number of insects. The increasing use of insecticides in the agricultural field is associated with a significant risk to water resources and aquatic systems. Thus the degradation of such compounds, after fulfillment of their insecticidal role, is essential to eliminate or minimize the contamination of water. The degradative treatment of acetamiprid insecticide from artificially contaminated water by water soluble colloidal MnO2 in acidic medium (HClO4) has been studied spectrophotometrically in the absence and presence of surfactants. The experiments have been performed under the pseudo-first-order reaction conditions with respect to MnO2. The degradation kinetics has been observed to be first-order with respect to MnO2 while fractional-order in both acetamiprid and HClO4. The anionic surfactant, sodium dodecyl sulfate (SDS) has been observed to be ineffective. On the other hand the reaction in the presence of cationic surfactant, cetyltrimethyl ammonium bromide (CTAB) could not be followed as well because it possesses a positive charge opposite to that of colloidal MnO2 causing flocculation and therefore could not be studied further. However, the addition of non-ionic surfactant, polyethylene glycol tert-octylphenyl ether (TX-100) accelerates the reaction rate. The catalytic effect of TX-100 has been discussed in the light of the available mathematical model. The kinetic data have been exploited to generate the various activation parameters for the oxidative degradation of acetamiprid by colloidal MnO2 in the absence and presence of non-ionic surfactant, TX-100.

Effect of addition of non ionic surfactant on the gas sensing properties of CuO films

Non ionic surfactant (Poly ethylene glycol (PEG-400)) has been used as dispersing and stabilizing agent along with citric acid in the sol-gel reaction to synthesize nanocrystalline CuO structures The decomposed gel sample calcined at temperature of 400°C has been assembled on glass substrate using an organic binder to form thick film sensor. The X-ray diffraction study of samples shows the formation of CuO as dominant phase in as decomposed gel and calcined CuO powder samples. Surfactant addition in precursor results in the decrease of crystallite size and leads to uniform distribution of CuO aggregates as noticed in the SEM micrographs. The activation energy of charge carrier in thick film samples has been investigated by two probe technique and is found to be of the order of 0.24 eV. Gas sening measurements on the samples performed at room temperature for analyte (ammonia gas) show an increase in response (4 times) as compare to sample formed by same procedure without surfactant.

Organofilization of Smectite Clay from Pedra Lavrada, PB, with Nonionic Surfactant

The petroleum industry has been investing for many years in the use of smectite as dispersant agent in the composition of oil-based and water-based fluids for drilling oil wells. The State of Paraíba is one of the largest producers of such clays and new deposits have been recently discovered in the regions of Cubati and Pedra Lavrada, causing many expectations for the expansion of the national mineral production. The objective of the present work is the organofilization of smectite clay from Pedra Lavrada, PB, through the addition of nonionic surfactant. After organofilization, the clay was characterized through X-ray diffraction and Foster swelling, so that the most suitable surfactant could be chosen for diesel as organic dispersant media. The results show that the incorporation of the surfactant used with the clay caused a significant increase in the interlamellar distance, and that the dispersions presented rheological properties that meet Petrobras' specifications for the use of organoclays in non aqueous based drilling fluids. Keywords: Smectite, drilling fluids, organofilization.

Biodegradation of complex hydrocarbons in spent engine oil by novel bacterial consortium isolated from deep sea sediment

Complex hydrocarbon and aromatic compounds degrading marine bacterial strains were isolated from deep sea sediment after enrichment on spent engine (SE) oil. Phenotypic characterization and phylogenetic analysis of 16S rRNA gene sequences showed the isolates were related to members of the Pseudoalteromonas sp., Ruegeria sp., Exiguobacterium sp. and Acinetobacter sp. Biodegradation using 1% (v/v) SE oil with individual and mixed strains showed the efficacy of SE oil utilization within a short retention time. The addition of non-ionic surfactant 0.05% (v/v) Tween 80 as emulsifying agent enhanced the solubility of hydrocarbons and renders them more accessible for biodegradation. The degradation of several compounds and the metabolites formed during the microbial oxidation process were confirmed by Fourier transform infrared spectroscopy and Gas chromatography–mass spectrometry analyses. The potential of this consortium to biodegrade SE oil with and without emulsifying agent provides possible application in bioremediation of oil contaminated marine environment.

A mechanistic dissection of polyethylenimine mediated transfection of CHO cells: to enhance the efficiency of recombinant DNA utilization.

In this study, we examine the molecular and cellular interactions that underpin efficient internalization and utilization of polyethylenimine (PEI):DNA complexes (polyplexes) by Chinese Hamster Ovary (CHO) cells. Cell surface polyplex binding and internalization was a biphasic process, consisting of an initial rapid Phase (I), lasting approximately 15 min, followed by a slower second Phase (II), saturating at approximately 240 min post transfection. The second Phase accounted for the majority (60-70%) of polyplex internalization. While cell surface heparan sulphate proteoglycans (HSPGs) were rapidly cointernalized with polyplexes during Phase I, cell surface polyplex binding was not dependent on HSPGs. However, Phase II polyplex internalization and HSPG regeneration onto the surface of trypsinized cells occurred at similar rates, suggesting that the rate of recycling of HSPG-containing membrane to the plasma membrane limits Phase II internalization rate. Under optimal transfection conditions, polyplexes had a near neutral surface charge (zeta potential) and cell surface binding was dependent on hydrophobic interactions, being significantly inhibited by both chemical sequestration of cholesterol from the plasma membrane and addition of nonionic surfactant. Induced alterations in polyplex zeta potential, using ferric (III) citrate to decrease surface charge and varying PEI:DNA ratio to increase surface charge, served to inhibit polyplex binding or reduce secreted alkaline phosphatase reporter expression and cell viability, respectively. To increase polyplex hydrophobicity and internalization an alkylated derivative of PEI, propyl-PEI, was chemically synthesized. Using Design of Experiments-Response Surface Modeling to optimize the transfection process, the function of propyl-PEI was compared to that of unmodified PEI in both parental CHO-S cells and a subclone (Clone 4), which exhibited superior transgene expression via an increased resistance to polyplex cytotoxicity. The combination of propyl-PEI and Clone 4 doubled the efficiency of recombinant DNA utilization and reporter protein production. These data show that for maximal efficacy, strategies to increase polyplex internalization into cells must be used in concert with strategies to offset the inherent cytotoxicity of this process.

Study of Organic Surfactant Sorption in Organophilic Clays

Bentonite clays, due to an immense variety of applications, are widely studied. Yet currently, organically modified bentonite clays studies have been increasing. The methods most studied involve addition of ionic or non-ionic surfactants to synthesize organophilic clays. The synthesis can be performed in two ways: by ion exchange (double replacement reaction chemistry), or by ion-dipole interaction where organic molecules are adsorbed on the surface of clay. The present work studies the sorption mechanisms of ionic and non-ionic surfactants to the surface of bentonite clays, thus making them organophilic. The results for the sorption experiments were obtained by adjusting the parameters of known mathematical models to the experimental data, the linear, and Freundlich models gave the best results for the sorption isotherms.