Dodecyltrimethylammonium Chloride Research Articles

Highly Stable Perovskite Solar Cells with Protective Layers Obtained via Interfacial Modification

Currently, achieving both high efficiency and long‐term stability is crucial for the successful application of perovskite solar cells (PSCs). Grain boundary (GB) defects significantly impact the stability of PSCs, and passivating these GBs remains a major challenge. Herein, the surfactant dodecyltrimethylammonium chloride (DTAC) is dissolved in low‐polarity chlorobenzene (CB) at 58 °C to modify the interface of MAPbI3 film, and DTAC reacts with MAPbI3 film surface to generate a protective layer that can be covered on the perovskite grains, effectively reducing the expose GBs. Additionally, the hydrophobic alkyl chains of DTA+ and the strong chemical bond between the Cl− and Pb2+ ions further enhance the resistance of the perovskite surface layer to heat, moisture, and oxidation. Due to the passivation of iodine vacancy defects, the photo‐stability of unencapsulated DTAC devices is significantly improved. By passivating surface and GBs defects of the MAPbI3 perovskite crystals, the power conversion efficiency of the low‐temperature carbon‐based PSCs treated by DTAC is 15.03% compared to 13.97% for the control device. This study offers another referable strategy for enhancing the thermal, moisture, light, and oxygen stability of perovskite materials while considering the photovoltaic performance of devices.

Re-engineering and regulating molecular architecture of synthetic capsaicin for enhanced water-based degradation performance

Synthetic capsaicin, also known as pelargonic acid vanillylamide (PAVA), constitutes the primary component in riot control agents. Due to the propensity of PAVA agglomerated in aqueous environments, the interaction between the active site of PAVA molecular and catalyst was restricted, consequently reducing its degradation efficiency in water-based oxidizing agents. This study used a cationic surfactant, dodecyl trimethyl ammonium chloride (DTAC), in combination with KOH for the precise regulation and arrangement of PAVA molecules, resulting in the formation of a distinctive hydrophilic structure. This approach resolved its poor solubility in aqueous solutions while the relationship between solubility and degradation rate was obtained. The frontier orbital distribution and surface electrostatic potential distribution of PAVA molecular were predicted through first-principles calculation. The mechanism of PAVA solubilization was studied by 1H NMR techniques and infrared spectroscopy methods. The results showed that KOH substitutes the phenolic hydroxyl group “–OH” of PAVA, forming potassium phenoxide “–OK”, which enhanced the solubility of PAVA in water. Additionally, KOH might reduced the surface tension in the solution. It promotes the formation of the DTAC/PAVA complex micelle structure, which exhibited the PAVA agglomerates to exposing the catalytic activation reaction sites and accelerating the catalytic oxidation.

Molecular Dynamic Simulations of Aqueous Micellar Organometallic Catalysis: Methane Functionalization as a Case Study.

Molecular Dynamics (MD) simulations constitute a powerful tool that provides a 3D perspective of the dynamical behavior of chemical systems. Herein the first MD study of the dynamics of a catalytic organometallic system, in micellar media, is presented. The challenging methane catalytic functionalization into ethyl propionate through a silver-catalyzed process has been targeted as the case study. The intimate nature of the micelles formed with the surfactants sodium dodecylsulfate (SDS) and potassium perfluorooctane sulfonate (PFOS) has been ascertained, as well as the relative distribution of the main actors in this transformation, namely methane, the diazo reagent and the silver catalyst, the latter in two different forms: the initial compound and a silver-carbene intermediate. Catalyst deactivation occurs with halide containing surfactants dodecyltrimethylammonium chloride (DTAC) and Triton X-100. Computed simulations allow explaining the experimental results, indicating that micelles behave differently regarding the degree of accumulation and the local distribution of the reactants and their effect in the molecular collisions leading to net reaction.

Molecular Dynamic Simulations of Aqueous Micellar Organometallic Catalysis: Methane Functionalization as a Case Study

AbstractMolecular Dynamics (MD) simulations constitute a powerful tool that provides a 3D perspective of the dynamical behavior of chemical systems. Herein the first MD study of the dynamics of a catalytic organometallic system, in micellar media, is presented. The challenging methane catalytic functionalization into ethyl propionate through a silver‐catalyzed process has been targeted as the case study. The intimate nature of the micelles formed with the surfactants sodium dodecylsulfate (SDS) and potassium perfluorooctane sulfonate (PFOS) has been ascertained, as well as the relative distribution of the main actors in this transformation, namely methane, the diazo reagent and the silver catalyst, the latter in two different forms: the initial compound and a silver‐carbene intermediate. Catalyst deactivation occurs with halide containing surfactants dodecyltrimethylammonium chloride (DTAC) and Triton X‐100. Computed simulations allow explaining the experimental results, indicating that micelles behave differently regarding the degree of accumulation and the local distribution of the reactants and their effect in the molecular collisions leading to net reaction.

Effects of Dodecyltrimethylammonium chloride (DAC) micelle’s shape transition on chemical enhanced oil recovery; experimental & mathematical modeling study

Surfactants are widely used for enhanced oil recovery (EOR) purposes by reducing interfacial tension (IFT) of oil–water phases and wettability alteration. Some surfactants with viscoelastic properties can be used as mobility control agents due to enhanced viscosity resulting from the spherical-to-cylindrical shape transition of micelles. Dodecyltrimethylammonium chloride (DAC) shows viscoelastic behavior coupled with dominantly cylindrical shape of the micelle in ambient conditions. Nevertheless, using DAC as an IFT reduction and mobility control agent needs to be industrialized for actual operating conditions. In this study, DAC, as a cationic surfactant, was experimentally studied in reservoir conditions considering dominantly cylindrical micelles for the first time. Results showed that the viscosity of DAC solution is a strong function of DAC concentration, especially at high temperature and high salinity conditions, while it does not depend on pressure significantly. Transmission electron microscope (TEM) images were taken for a better understanding of DAC micellar structures. Analysis of the TEM results indicated the shape transition of the micelles from small spherical to large cylindrical at higher concentrations of DAC. IFT of DAC microemulsion was studied for wide ranges of temperature and DAC concentration, ruling out any significant effect of the temperature on the IFT trend line. A general mathematical model for predicting the viscosity of surfactant solution was developed and evaluated for real reservoir conditions by including all effective terms. Results showed a very good agreement with experimental data of DAC and Cetyltrimethyl ammonium bromide (CTAB, as per previous studies), justifying the applicability of the developed model for predicting the viscosity wherever experimental data is unavailable. Core flood tests were performed with saltwater (SW) and DAC solutions with spherical (SS) and cylindrical (SC) micelles as injecting phases for evaluation of IFT reduction and mobility control effects. Results showed an additional recovery factor of 13 % for SS and 23 % for SC in comparison with SW injection.

Ecotoxicity and rapid degradation of quaternary ammonium compounds (QACs) subjected to combined vacuum UV and UV-C treatment

Quaternary ammonium compounds (QACs) are active ingredients in a palette of commercially available disinfectants, sanitizers, and biocides. QACs are widely used because of their broad-spectrum antimicrobial properties but the ubiquitous uses have resulted in frequent detection in aquatic and terrestrial matrices including domestic wastewater, surface waters, urban soils and sediments. An increased domestic QACs consumption has increased the environmental occurrence, and investigation of mitigation methods and effects on non-target organisms are in demand. In this study, we examined the potential ecotoxicity of six QACs and investigated the effect of combined vacuum UV (185 nm) and UV-C (254 nm) irradiation (VUV/UVC) on degradation and mitigation of ecotoxicity of QACs. The study showed that combined VUV/UVC irradiation facilitated rapid degradation of benzalkonium chloride, benzethonium chloride, didecyldimethylammonium chloride, dodecyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride. The estimated half-lives varied between 2 and 7 min, and degradation was affected by the initial QAC concentrations, the UV fluence, and the water matrix. The potential ecotoxicity of QACs and VUV/UVC treated QACs was examined using a battery of test organisms that included the luminescent bacterium Aliivibrio fischeri, the gram-negative and gram-positive bacteria Escherichiacoli and Enterococcus faecalis, the freshwater microalga Raphidocelis subcapitata, and the crustacean Daphia magna. The potential for trophic transfer of QACs was investigated in a simplified aquatic food web. Test organisms from different trophic levels were included to assess adverse effects of bioactive compounds in VUV/UVC treated samples including transformation products. The study showed that several QACs were highly toxic to aquatic test organisms with EC50 and/or EC20 values < 1 μM. VUV/UVC treatment of QACs resulted in substantial photolysis of the parent compounds and comprehensive mitigation of the ecotoxicity potential. VUV/UVC represent an attractive oxidation technology for abatement QACs in contaminated water because the process does not require addition of catalysts or precursors.

Greener process to prepare and scale-up zwitterionic macro cyclic dihydroxy-aza-crown ether and their corresponding supramolecular pairs to enhanced oil recovery application

This manuscript discusses a green and clean route to prepare macro cyclic dihydroxy-aza-crown ether (MC-DACE) compounds, their zwitterionic derivatives, and the corresponding supramolecular pairs with a cationic surfactant. A conventional one vessel two-step process developed as the synthetic route. The first step consists of a reaction without solvent to obtain MC-DACE, and the next stage occurs in aqueous to get zwitterionic macro cyclic dihydroxy-aza-crown ether (ZWMC-DACE). We prepared the first instance in the lab scale, and a subsequent scale-up process was carried out. Green metrics were determined and performed through Andraos pentagon, showing that synthetic approaches are greener and environmentally friendly concerning other routes to prepare analog compounds. These ZWMC-DACE and corresponding supramolecular pairs with dodecyl trimethyl ammonium chloride (DTAC) have been tested with good performance in the enhanced oil recovery (EOR) application to study their wettability-altering and non-emulsion formation.

Insight into anionic and cationic flotation discrepancy of quartz with altered surface roughness by acid etching

Surface roughness has a significant effect on mineral flotation. In this study, the surface roughness of quartz was altered using HF etching and their values before and after acid etching were quantified using AFM. Anionic flotation experiments with CaCl2 as activator and sodium oleate (NaOL) as collector, and cationic flotation experiments with dodecyl trimethyl ammonium chloride (DTAC) as collector were carried out for both the raw and acid-etched samples. The results showed that acid etching is beneficial to increase the surface roughness of quartz. The rougher quartz particle has higher recovery and quicker flotation rate during anionic flotation, while lower recovery and slower flotation rate during cationic flotation. The role of surface roughness in the discrepancy of these two flotations was investigated in terms of surface chemistry by X-ray photoelectron spectroscopy, UV spectrophotometer, surface force tensiometer, and zeta potential analyzer. The rougher sample was confirmed to have more unsaturated interfacial active sites, adsorbed more Ca2+ and NaOL, and exhibited higher hydrophobicity in anionic flotation. Differently, the rougher sample was verified to have less interfacial negative charge, adsorbed less DTAC, and exhibited weaker hydrophobicity in cationic flotation. Taken together, the surface roughness altered by acid etching has different effects on the adsorption capacity of NaOL and DTAC, thus affecting the wettability and floatability of quartz particles inconsistently in anionic and cationic flotation.

Individual and combined cytotoxicity effects of positively charged polystyrene nanoplastics and ionic surfactants on budding yeast Saccharomyces cerevisiae

It is of crucial importance to understand the impact of micro/nanoplastics contaminated with the other pollutants on microorganisms in the environment. In the present paper, we have investigated the individual and combined cytotoxicity effects of positively charged fluorescence-labeled polystyrene nanoparticles (pPS-NPs; 115 and 204 nm in diameter) and ionic surfactants [sodium dodecyl sulfate (SDS) and dodecyltrimethylammonium chloride (C12TAC)] on budding yeast Saccharomyces cerevisiae after a short-time exposure (0.5 h) in a 5-mM NaCl aqueous solution. In the absence of surfactants, the smaller 115-nm pPS-NPs were more cytotoxic than the larger 204-nm pPS-NPs. In the absence of pPS-NPs, the cationic surfactant of C12TAC was more cytotoxic than the anionic surfactant of SDS, though these two ionic surfactants have the hydrophobic alkyl chains of the same length and the oppositely charged headgroups in the same magnitude. The addition of SDS decreased the number of pPS-NPs adhered on a negatively charged yeast cell to reduce the cytotoxicity, whereby the combined toxicity effect was considered as counteracting action. Although some addition of C12TAC hardly influenced the number of pPS-NPs adhered on a yeast cell, the synergistic cytotoxicity action of the pPS-NPs and C12TAC was observed.

Quaternary ammonium compounds promoted anoxic sludge granulation and altered propagation risk of intracellular and extracellular antibiotic resistance genes.

Surfactants could influence sludge morphology and disinfectants were linked to antibiotic resistance genes (ARGs). Thus, the response of activated sludge and ARGs to long-term quaternary ammonium compounds (QACs) exposure required further investigation, which is a popular surfactant and disinfectant. Here, three sequencing batch reactors were fed with 5mg/L most frequently detected QACs (dodecyl trimethyl ammonium chloride (ATMAC C12), dodecyl benzyl dimethyl ammonium chloride (BAC C12) and didodecyl dimethyl ammonium chloride (DADMAC C12)) for 180 d. The long-term inhibitory effect on denitrification ranked: DADMAC C12>BAC C12>ATMAC C12. Besides, obvious granular sludge promoted by the increase of α-Helix/(β-Sheet + Random coil) appeared in DADMAC C12 system. Moreover, intracellular ARGs increased when denitrification systems encountered QACs acutely but decreased in systems chronically exposed to QACs. Although replication and repair metabolism in ATMAC C12 system was higher, ATMAC C12 significantly promoted proliferation of extracellular ARGs. It was noteworthy that the propagation risk of extracellular ARGs in sludge increased significantly during sludge granulation process, and intracellular sul2 genes in sludge and water both increased with the granular diameter in DADMAC C12 system. The universal utilization of QACs may enhance antibiotic resistance of bacteria in wastewater treatment plants, deserving more attention.

Surface change of microplastics in aquatic environment and the removal by froth flotation assisted with cationic and anionic surfactants

Microplastics (MPs) are increasingly released into the environment due to the widespread usage and improper management of plastics. Considerable research efforts have been devoted to the remediation of MPs. Froth flotation has been demonstrated as an effective method to remove MPs in water and sediment. However, there is a lack of knowledge on the regulation of the hydrophobicity/hydrophilicity of MPs surfaces. We found that exposure to the natural environment resulted in the increased hydrophilicity of MPs. The flotation efficiencies of polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), and polyethylene glycol terephthalate (PET) MPs decreased to zero after six months of natural incubation in rivers. According to various characterizations, the hydrophilization mechanism is mainly correlated with surface oxidation and the deposition of clay minerals. Inspired by surface wettability conversion, we applied surfactants (collectors) to enhance MPs hydrophobicity and flotation efficiency. Anionic sodium oleate (NaOL) and cationic dodecyl trimethyl ammonium chloride (DTAC) were used to regulate surface hydrophobicity. The effects of collector concentration, pH, conditioning time, and metal ions on MPs flotation were thoroughly elucidated. Characterizations and adsorption experiments were performed to describe the heterogeneous adsorption of surfactants on MPs surfaces. The interaction between surfactants and MPs was explained through density functional theory (DFT) simulations. The dispersion energy between hydrophobic hydrocarbon chains attracts collectors on the MPs surface, and the collector molecules wrap and laminate to MPs surfaces. Flotation using NaOL exhibited a higher removal efficiency, and NaOL was environmentally friendly. Subsequently, we investigated the activation of Ca2+, Fe3+, and Al3+ to further improve the collecting efficiency of NaOL. Under the optimized conditions, MPs in natural rivers could be removed by froth flotation. This study shows the great promise of froth flotation for the application of MPs removal.

Photoionization of 3-Methylindole Embedded in Sodium Dodecyl Sulfate and Dodecyltrimethylammonium Chloride Micelles: Migration of Electrons Generated in Micelle Cores and Their Solvation in Outside Water

Electrons were generated in the core of micelles formed by negatively charged sodium dodecyl sulfate (SDS) or positively charged dodecyltrimethylammonium chloride (DTAC) by photoionization of 3-methylindole embedded in the core. The electrons were hydrated after they moved out of the core to the outer aqueous phase. These processes were monitored with femtosecond time-resolved absorption spectroscopy. The migration of electrons from the micelle core to the outer aqueous phase was faster than the instrumental response time of 200 fs. Hot electrons in the aqueous phase were produced in ≤320 fs. There was no significant difference observed for the micellar solutions of negatively charged SDS and positively charged DTAC, or for water. The geminate recombination between the electrons and the radical cations was hindered to a large extent once the electrons hydrated at the outer aqueous phase were separated from the radical cations remaining in the micelle core.

Unprecedented Regioselective Deuterium‐Incorporation of Alkyltrimethylammonium Chlorides and Raman Analysis

AbstractAlkyltrimethylammonium chlorides (ATACs) are widely utilized as cationic surfactants in various scientific fields. Furthermore, deuterium‐incorporated compounds can be powerful tools for elucidating the complicated morphologies of molecules with high molecular weights. Dodecyltrimethylammonium chloride (DTAC), as a representative ATAC, underwent the regioselective multi‐deuteration of alkylamine moiety, except for α and β‐positions. Deuteration was performed under Pt/C and Ru/C‐catalyzed conditions in 2‐PrOH and D2O. The stimulated Raman scattering (SRS) revealed the specific signals of multi‐deuterated DTAC in the silent region.

An investigation into shale swelling inhibition properties of dodecyltrimethylammonium chloride (DTAC) for water-based drilling fluids

Shale formations adsorb water and swell when they are in contact with water-based drilling fluids due to the content of active clay minerals. Shale swelling in the well wall is one of the main challenges of drilling operations and causes many problems and damages. Modifying drilling mud with shale swelling inhibitors is one of the solutions to this challenge. Recently, amines and their derivatives have been considered by researchers due to their ability to control the swelling of shale layers and the range of properties that can be adapted to any drilling conditions. In this study, Dodecyltrimethylammonium Chloride (DTAC) was investigated as a new shale stabilizer and swelling inhibitor. Various tests such as bentonite sedimentation, bentonite inhibition, shale sample recovery and dynamic linear swelling were used for this study. Wettability, zeta potential, isothermal water adsorption and thermogravimetric analysis (TGA) tests were performed to evaluate the mechanism of action of this amine-based shale swelling inhibitor. Based on the results, DTAC shows good inhibition power in controlling and reducing the swelling of shale and bentonite samples at both low and high temperatures, even at low concentrations. DTAC is well-compatible with other common additives in drilling fluids. On the other hand, this amine shows a relatively stronger function than Cetyltrimethyl Ammonium Bromide (CTAB) and Ammonium Chloride (NH4Cl). Adsorption of DTAC molecules on the surface of charged plates of bentonite particles reduces the negative charges of these plates, makes inaccessible places available on the plates of water molecules, increases their hydrophobicity and finally reduces the sensitivity of surfaces to adsorption of water molecules, which leads to stabilization of shale samples and bentonite particles against contact with aqueous media.

Sodium tetratungstate/tungsten oxide films prepared with dodecyltrimethylammonium chloride as structuring agent

Abstract&#x0D; The multiple forms of structuring transition metal anions in solution are important aspects to be taken into account in obtaining oxides of these metals by the sol-gel method. The formation of polyanions in aqueous media can produce a variety of structures in the solid state. Films were obtained through sol-gel method with sodium tungstate as precursor and dodecyltrimethylammonium chloride (DTAC) as structuring agent, after calcined at 700 °C in air. The films, structured as nanospheres, were composed mainly of triclinic sodium tetratungstate and monoclinic tungsten oxide. The cationic surfactant interacts in aqueous media with the precursor, affecting the obtained films' final morphology, without affecting their crystal structure. Their photocatalytic properties were also evaluated.&#x0D; Keywords: Colloidal synthesis; sol-gel; photocatalysis.&#x0D; Resumo&#x0D; Filmes de tetratungstato de sódio/óxido de tungstênio preparados com cloreto de dodeciltrimetilamônio como agente estruturante&#x0D; As múltiplas formas de estruturação de ânions de metais de transição em solução revelam aspectos importantes a ser levados em consideração na obtenção de seus óxidos pelo método sol-gel. Um desses aspectos é a formação de poliânions em meio aquoso, que pode produzir uma variedade de estruturas no estado sólido. Desta feita, foram obtidos filmes através do método sol-gel utilizando-se, como precursor, de tungstato de sódio e, como agente estruturante, cloreto de dodeciltrimetil amônio, que foram posteriormente calcinados a 700 ºC em ar. Observou-se que os filmes, estruturados como nano esferas, eram compostos principalmente de tetratungstato de sódio triclínico e óxido de tungstênio monoclínico. Por sua vez, conclui-se que o surfactante catiônico interage em meio aquoso com o precursor e afeta a morfologia final dos filmes obtidos, no entanto tem pouca influência nas suas estruturas cristalinas. Faz-se importante destacar que as propriedades fotocatalíticas foram também avaliadas na presente pesquisa.&#x0D; Palavras-chave: Síntese coloidal; sol-gel; fotocatálise. &#x0D; Resumen&#x0D; Películas de tetratungstato de sodio/óxido de tungsteno preparadas con cloruro de dodeciltrimetilamonio como agente estructurante&#x0D; Las múltiples formas de estructurar los aniones de metales de transición en solución son aspectos importantes a tener en cuenta a la hora de obtener sus óxidos por el método sol-gel. La formación de polianiones en medios acuosos puede producir una variedad de estructuras en estado sólido. Se produjeron películas por medio del método sol-gel utilizando tungstato de sodio como precursor y cloruro de dodeciltrimetilamonio como agente estructurante, luego calcinadas a 700 ºC en aire. Las películas, estructuradas como nanoesferas, estaban compuestas principalmente de tetratungstato de sodio triclínico y óxido de tungsteno monoclínico. El tensioactivo catiónico interactúa en medio acuoso con el precursor, afectando la morfología final de las películas obtenidas, pero tiene poca influencia sobre su estructura cristalina. Fueron evaluadas también las propiedades fotocatalíticas.&#x0D; Palabras clave: Síntesis coloidal; sol-gel; fotocatálisis.

Chemical Agglomeration to Enhance Blast Furnace Dust Capture Efficiency in Wet Electrostatic Precipitators

Wet electrostatic precipitators (WESPs) are increasingly used in iron and steel plants and coal-fired power plants due to their higher efficiency at capturing fine particles than conventional dry-type precipitators. In order to achieve ultra-pure purification of dust in steel plant gas, we propose an improved method that involves adding a chemical coagulant and a surfactant to a WESP. The effects of the type and concentration of chemical coagulant and surfactant on the agglomeration effect and dust removal efficiency of blast furnace dust were investigated. The results show that the addition of a chemical coagulant could promote the agglomeration of blast furnace dust particles, and the D50 of dust particles increased from 5.8 to 15.0 μm after the addition of xanthan gum (XTG). The best increase in the blast furnace’s dust particle removal occurred at a concentration of 10 mg/L of XTG, and the dust removal efficiency reached 97.59%. The surfactant dodecyl trimethyl ammonium chloride (DTAC) improved the dust removal efficiency of blast furnace dust when added alone. The dust removal efficiency reached 97.82% when 10 mg/L of XTG and 9 mg/L of DTAC were added synergistically. The addition of a chemical coagulant and surfactant promoted the agglomeration of blast furnace dust and enhanced the dust capture effect of a WESP. We thus demonstrated that we can improve the efficiency of WESP in the future via chemical coagulation. The authors will further study the effect of multi-factor synergistic coupling on the chemical coagulation method in WESPs.

The effect of quaternary ammonium salts with different chain lengths on copper filling behavior in blind holes of printed circuit board

The rapid and defect free blind hole copper super filling is the key technology to ensure the quality and development of printed circuit boards (PCBs). The linear quaternary ammonium compounds with a low molecular weight are expected to act as a potential suppressor for blind hole copper filling. Here, three quaternary ammonium salts with different molecular chain lengths (the dodecyl trimethyl ammonium chloride, the cetyl trimethyl ammonium chloride and the stearyl trimethyl ammonium chloride) were selected to study the effects of the molecular chain length of quaternary ammonium salt on the copper filling behavior of the PCB blind holes. The electrochemical results show that the three quaternary ammonium salts show greater inhibition ability on copper deposition compared with the traditional additives (polyethylene glycol (PEG) and Cl−) and furthermore, the suppressor effect becomes stronger with the increase of molecular weight. The blind hole copper filling experiment of PCB is also carried out to study the copper filling capacity of three quaternary ammonium salts. The filling experiment reveals that compared with the traditional suppressors (PEG and Cl−), the filling quality of blind hole copper is significantly improved when the three quaternary ammonium salts are used as suppressors. Moreover, under the coordination of accelerator (bis (3-sulfopropyl) disulfide (SPS)), the three quaternary ammonium salts can realize more rapid copper super filling without chloride ion in the electrolyte. Cross-section and surface morphological analysis further illuminates that the quaternary ammonium salt as an suppressor can also more effectively inhibit the deposition of copper on the PCB surface and reduce the roughness of the copper layer. The present results imply that quaternary ammonium salts have greater advantages for copper filling and are expected to replace traditional suppressors as new suppressors.

Comparison of pool boiling heat transfer performance between aqueous cationic and anionic surfactant solutions with similar ionic group

Pool boiling in aqueous surfactant solution is found to have a better heat transfer performance than that in distilled water. The present study intends to investigate the effect of functional ionic group in cationic or anionic surfactant on pool boiling performance. Two pairs of surfactants, namely, cationic surfactants of Dodecyltrimethylammonium bromide (DTAB) / Dodecyltrimethylammonium chloride (DTAC) and anionic surfactants of Sodium dodecyl sulfonate (SD-Sulfonate) / Sodium dodecyl sulfate (SD-Sulfate), are added into distilled water with a mass concentration of 100–3200 ppm. Boiling performance and thermophysical properties of the corresponded surfactant solutions are measured and compared with water. The bubble behaviour and surface wettability are also analyzed. Results indicate that the surfactant solutions can generally increase the heat transfer coefficient (HTC) compared with water and a higher concentration solution usually owns a greater HTC. The maximum relative HTC enhancement can reach up to 2.33 times. The reduction in surface tension and an additional repulsion force due to the addition of surfactant result in a denser nucleate site, a smaller bubble departure diameter and a faster bubble departure frequency, which results in a higher HTC. The surface tension reduction caused by surfactant addition and the boiling process make the copper surface more wettable, resulting in a higher critical heat flux (CHF). However, the surfactant also makes the fresh water supply difficult at a high heat flux and subsequently results in a lower CHF. The CHF is comprehensively affected by the surface wettability of boiling surface and surfactant concentration and their relative strength determines the final magnitude of CHF. The surfactants with a same or similar functional ionic group have similar boiling heat transfer performance in aqueous solutions. The present study can provide meaningful guidance for further pool boiling studies and relevant highly efficient heat exchanger design.

Efficient depolymerization of polyethylene terephthalate (PET) and polyethylene furanoate by engineered PET hydrolase Cut190

The enzymatic recycling of polyethylene terephthalate (PET) can be a promising approach to tackle the problem of plastic waste. The thermostability and activity of PET-hydrolyzing enzymes are still insufficient for practical application. Pretreatment of PET waste is needed for bio-recycling. Here, we analyzed the degradation of PET films, packages, and bottles using the newly engineered cutinase Cut190. Using gel permeation chromatography and high-performance liquid chromatography, the degradation of PET films by the Cut190 variant was shown to proceed via a repeating two-step hydrolysis process; initial endo-type scission of a surface polymer chain, followed by exo-type hydrolysis to produce mono/bis(2-hydroxyethyl) terephthalate and terephthalate from the ends of fragmented polymer molecules. Amorphous PET powders were degraded more than twofold higher than amorphous PET film with the same weight. Moreover, homogenization of post-consumer PET products, such as packages and bottles, increased their degradability, indicating the importance of surface area for the enzymatic hydrolysis of PET. In addition, it was required to maintain an alkaline pH to enable continuous enzymatic hydrolysis, by increasing the buffer concentration (HEPES, pH 9.0) depending on the level of the acidic products formed. The cationic surfactant dodecyltrimethylammonium chloride promoted PET degradation via adsorption on the PET surface and binding to the anionic surface of the Cut190 variant. The Cut190 variant also hydrolyzed polyethylene furanoate. Using the best performing Cut190 variant (L136F/Q138A/S226P/R228S/D250C-E296C/Q123H/N202H/K305del/L306del/N307del) and amorphous PET powders, more than 90 mM degradation products were obtained in 3 days and approximately 80 mM in 1 day.Graphical

Modulating aggregation behaviour and surface properties of cationic & anionic surfactant with surface active ionic liquid 1-decyl-3-methylimidazolium chloride [C10mim][Cl]: Role of surfactant head group

Aggregation behaviour of two conventional surfactants dodecyl trimethylammonium chloride (DTAC) and sodium dodecyl sulphate (SDS) in aqueous medium, in the absence and presence of different wt% (0.02,0.05,0.10) of ionic liquid (IL), 1-decyl-3-methylimidazolium chloride [C10mim][Cl] and at various temperatures (298.15,303.15,308.15) K has been studied. The critical micelle concentration (CMC) of IL-added aqueous surfactant solutions were obtained by state of art techniques i.e., conductivity, UV–Vis, fluorescence spectroscopy and surface tension. Further, the CMC value have been utilised to obtain various thermodynamic parameters and interfacial properties by conductivity and surface tension method. The recovered parameters were used to understand the effect of IL on aqueous SDS/DTAC solutions. The structural changes that occurred in the mixed system (surfactants + IL [C10mim][Cl]) were also explored by fourier transform infrared spectroscopy.