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The effects of three straight-chain alkanes (n-pentane, n-heptane, and n-octane) on the phase behaviors of aqueous solutions of sodium lauryl sulfate and hexadecyl trimethylammonium bromide with ad...

Mesoporous silica materials were synthesized using tetraethoxysilane (TEOS) as precursor and liquid crystals (LCs) formed in mixtures of cationic cetyltrimethylammonium bromide (CTAB) and anionic s...

Three-dimensional nitrogen-doped carbon network incorporated with nickel@nickel oxide core-shell nanoparticles composite (3D NC/Ni@NiO) has been facilely prepared, self-templated by the cross-linked polyacrylamide aerogel precursor containing NiCl2. Characterizations reveal that the Ni@NiO nanoparticles distribute homogeneously in the 3D nitrogen-doped carbon matrix and the composite is of hierarchical porous structure. When used as supercapacitor electrode in a three-electrode system, the 3D NC/Ni@NiO exhibits enhanced electrical conductivity and excellent electrochemical performance, presenting a high specific capacitance (389F g−1 at 5 mV s−1), good rate capability (276 F g−1 at 100 mV s−1) and outstanding cycling performance (with the capacitance retention of 70.2% after 5000 charge-discharge cycles). This is due to the synergistic effects of conductive metallic nickel, pseudocapacitive nickel oxide as well as in situ nitrogen doping of carbon network. Moreover, an asymmetric supercapacitor (ASC) was fabricated with NC/Ni@NiO as positive electrode and active carbon as negative electrode. The ASC device exhibits a maximum energy density of 19.4 W h kg−1 at a power density of 700 W kg−1 and shows good cycling stability (73.8% capacity retention after 3000 cycles), indicating that it has great promise for practical energy storage and conversion application.

A novel and effective method for synthesis of mesoporous silica is reported in this paper. The method was based on the use of the tetraethoxysilane (TEOS) as precursor and the layered liquid crystals (LCs) as templates formed by cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS). The range of the LCs was determined by exploring the phase behavior of the system with different ratios and concentrations of CTAB and SDS. The effects of the ratio of CTAB/SDS and the ratio of H2O and TEOS (defined as R) on the properties of mesoporous materials were studied. The results indicated that the specific surface area of mesoporous silica increased initially and then decreased with the increase of both R value and CTAB in the positive region. SEM photos showed that the synthesized mesoporous silica had a distinct lamellar structure.

This study explores the effects of apolar organic additives (AOAs) of n-hexane, cyclohexane, 1,3,5-trimethylbenzene (TMB) and 1,3,5-triisopropylbenzene (TIPB), on the expansion of hydrophobic space...

The photoresponsive wormlike micelles constructed by Gemini surfactants and cinnamate derivatives play a great role in the field of smart materials. However, how the structure of cinnamate derivatives affects the photoresponsive behavior of micelles is still a hotspot for scientists to research. Here, three kinds of aromatic salts with different ortho-substituted groups including trans- o-methoxy cinnamate ( trans-OMCA), trans- o-hydroxy cinnamate ( trans-OHCA), and trans-cinnamate ( trans-CA) were introduced into Gemini surfactant 12-3-12·2Br- aqueous solutions to construct photoresponsive wormlike micelles through their noncovalent interactions. Their properties were researched using the rheological method, cryo-transmission electron microscopy, and 1H NMR and two-dimensional nuclear Overhauser effect spectra. The results show that these cinnamate derivatives could well construct wormlike micelles with 12-3-12·2Br-. Furthermore, subtle differences in the ortho substituents' structure have a significant effect on the photoresponsive behavior of formed wormlike micelles. Specifically, the zero viscosity (η0) of 40 mM 12-3-12·2Br-/24 mM trans-OHCA mixed solution decreases from 26.72 to 2.6 Pa·s with the shortening of the length of wormlike micelles after UV irradiation. Correspondingly, the η0 for the same ratio of 12-3-12·2Br-/ trans-OMCA decreases from 2.42 to 0.06 Pa·s and the wormlike micelles are transited into rodlike micelles and even spherical micelles after the same UV irradiation time. However, the variation of wormlike micelles in the 12-3-12·2Br-/ trans-CA system induced by UV light is not obvious with η0 being maintained at around 2.89 Pa·s. This study will help us better understand the effects of chemical groups on macrophenomena and microinteraction for micellar systems. It provides a theoretical basis for the construction of photoresponsive micelles, thus widening their application in the field of soft materials.

We have developed a facile quaternarization strategy to an ultrathin lamellar g-C3N4 ionic liquid nanostructure (IL-CNNS) via a nucleophilic substitution between the tertiary amino groups in tri-s-triazine subunits and n-butyl bromide. After functionalization, the obtained IL-CNNS composite exhibits the enhanced conductivity, dispersibility and stability owing to the formation of IL structure. This composite has been characterized by several spectroscopic techniques (FT-IR, XRD, XPS, TGA and TEM). The IL-CNNS modified electrode displays the larger effective surface area and the faster electron transfer rate, hence resulting in the superior electrocatalytic activity toward 2,4-Dichlorophenol (2,4-DCP). Under the optimal conditions, the proposed 2,4-DCP sensor gives rise to the wide linear range from 0.02 to 160 μM with a low detection limit (6.21 nM, S/N = 3) by amperometric method. The developed sensor has been applied to detect 2,4-DCP in water samples with satisfactory recoveries and stability. This quaternarization strategy may open up a new avenue to fabricate the layered carbon nitride IL nanostructure for electrochemical sensing applications.

The influence of 1-hexanol on the phase behavior of sodium dodecyl sulfate (SDS)/cetyltrimethyl ammonium bromide (CTAB)/NaBr/H2O system has been systematically investigated in this paper. The resul...

Photoresponsive systems with adjustable self-assembly morphologies and tunable rheological properties have aroused widespread concern of researchers in recent years because of their prospect applications in controlled release, microfluidics, sensors, and so forth. In this paper, we combine a cationic Gemini surfactant 12-3-12·2Br– and trans-2-methoxy-cinnamate (trans-OMCA) together to create a representative UV-responsive self-assembly system. The system displays abundant self-assembly behaviors, and the self-assemblies with different states and different scales including wormlike micelles, vesicles, and lyotropic liquid crystals (LCs) as well as an aqueous two-phase system (ATPS) are observed even at lower surfactant concentration. The UV-responsive behavior of the formed self-assemblies is investigated systematically. The results have shown that the photoisomerization of OMCA from trans form to cis form under UV light irradiation alters the hydrophobicity and steric hindrance effect of OMCA and thus aff...

The effect of 1-hexanol on the phase behavior of aqueous solutions of sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) has been systematically studied. The phase ranges of v...

Fabricating high-performance and low-cost bifunctional electrocatalysts for both oxygen evolution and reduction reactions is vital for the practical application of renewable energy conversion. Herein, a hybrid of Co3O4/Co active species incorporated in N-doped porous carbon matrix, denoted as Co3O4/Co-NPC, has been prepared using a scalable and facile method involving the carbonization of alginate composite after a Co ion exchange with sustainable seaweed biomass. The 3D Co3O4/Co-NPC exhibits good bifunctional oxygen electrocatalytic performance in alkaline medium. The proposed catalyst gives the smaller onset potential (1.450 V vs. RHE) and overpotential (277 mV) at 10 mA cm−2 current density, indicating a superior oxygen evolution reaction activity to commercial IrO2 catalyst. It also performs the excellent oxygen reduction catalytic activity with larger onset potential (0.91 V vs. RHE), more positive half wave potential (0.806 V vs. RHE) and bigger diffusion-limiting current density (−5.86 mA cm−2 at 0.4 V). The Co3O4/Co-NPC hybrid experiences an almost ideal 4e process with better long-term stability and anti-methanol ability than commercial Pt/C catalyst in 0.1 M KOH. The prominent bifunctional activity of Co3O4/Co-NPC can be due to the synergistic effects of the well dispersed Co3O4/Co active species and N-doped porous carbon nanostructure.

A Co-metal–organic-framework (MOF) crystal has been hydrothermally synthesized. Then the corresponding Co/nitrogen-doped porous carbon (Co/NPC) composite is fabricated by direct pyrolyzation of MOF without any precursor additive. The results reveal that the MOF-derived Co/NPC exhibits a porous structure with a surface area of 412 m2 g−1 and a narrow pore size distribution (from 1.8 to 4.9 nm). The doped N mainly occurs in pyridine N and graphitic N types with total content as 4.11 at.%, which is originated from the N-based ligands in MOF. As an efficient oxygen reduction reaction (ORR) catalyst, Co/NPC shows a more positive onset potential (0.91 V vs. RHE) with a diffusion-limited current density of 5.46 mA cm−2 at 0.3 V (vs. RHE). The rotating disk electrode and rotating ring-disk electrode results suggest that the Co/NPC catalyst experiences a nearly 4e pathway with a stronger methanol tolerance and better durability than commercial Pt/C catalyst in 0.1 M KOH. The excellent ORR catalytic activity of Co/NPC can be attributed to the N-doped porous carbon structure with incorporated metallic Co active species. This work affords a new strategy for preparation of non-noble metal ORR catalysts employing MOF as a precursor.

Antibacterial modification of polymers with potent biocides via an efficient and universal approach is very desirable in both academia and industry. A polysiloxane with both quaternary ammonium and N-chloramine was prepared via a facile three-step synthetic route. Poly(methylhydrosiloxane) (PMHS) was first reacted with 2-(dimethylamino)ethyl acrylate to introduce an ending tertiary amine that was subsequently quaternized with 3-(3-chloropropyl)-5,5-dimethylhydantoin (CPDMH). The 5,5-dimethylhydantoin moiety was then transformed into its N-chloramine counterparts by chlorination with tert-butyl hypochlorite to produce quaternary ammonium (quat)/N-chloramine polysiloxane. The CO2-philic quat/N-chloramine polysiloxane was interpenetrated into polyethylene terephthalate (PET) in supercritical carbon dioxide (scCO2) and formed a 70 nm biocidal layer. The synthetic procedures and interpenetration results were characterized with Fourier transform infrared spectroscopy (FTIR), 1H NMR, scanning electron microscopy...

The study focuses on the synthesis of mesoporous silica materials using liquid crystals (LCs) formed in an aqueous mixture of cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium dodec...

This work describes the synthesis of a nanocomposite consisting of Ag2O, silver nanoparticles and N,S-doped carbon quantum dots (Ag2O/Ag@NS-CQD). The NS-CQD were prepared by hydrothermal treatment of p-aminobenzenesulfonic acid. They act as both the reducing and stabilizing agent for synthesis of Ag2O/Ag@NS-CQD. The composite was characterized by UV-vis spectroscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The glassy carbon electrode (GCE) was modified by coating it with Ag2O/Ag@NS-CQD. It exhibits excellent amperometric response to catechol, typically at a low working potential of around 0.25 V. Under the best experimental conditions, the sensor has a wide linear response (0.2 to 180 μM) and a low detection limit (13 nM; at S/N = 3). The method was applied to analysis of spiked water samples and gave satisfactory results.

It is highly essential but challengeable to explore the earth-abundant and low-cost oxygen evolution reaction catalysts to replace Ir- or/and Ru-based ones. In this article, we report an in situ growth of ultrathin NiFe layered double hydroxide nanosheets on reduced graphene oxide in formamide aqueous solution followed by simple chemical reduction. These ultrathin layered double hydroxide nanosheets in the composite occur in single- or multi-layer forms on reduced graphene oxide matrix. Consequently, the obtained catalyst exhibits the enhanced BET surface area and electrochemically active surface area, and low mass transfer resistance. This electrocatalyst displays the excellent OER activity with a small onset potential of 233 mV. Additionally, it only requires an overpotential of 254 mV to achieving current density of 10 mA cm−2, and can gives a current density of 70.60 mA cm−2 at overpotential of 300 mV in 0.1 M KOH. It also demonstrates the robust long-time electrochemical durability.

Liquid crystals formed in aqueous mixtures of cationic and anionic surfactants were used as structure- directing templates for preparation of mesoporous silicas. For this purpose, micellar particle sizes and liquid crystal regions in the mixed system containing cetyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) were investigated by Melvin laser particle size analyzer and polarizers, respectively. The formation of large organized assemblies was closely related to both the total surfactant concentrations and mixing ratios. Micelles formed at low total concentration while liquid crystals formed at high total concentration. The mixtures of CTAB and SDS favored the formations of large organized assemblies when the molar fraction of CTAB was 0.30 or 0.70. Using tetraethoxysilane as precursor and liquid crystals as templates, mesoporous silicas were prepared at different total concentrations of surfactants when molar fraction of CTAB was fixed at 0.70. Transmission electron microscopy results revealed that ordered mesoporous silicas with lamellar pore channels were prepared. Nitrogen adsorption-desorption determinations showed that these materials exhibited a pore size about 4.5 nm. In addition, the surface areas increased significantly with the increase of total surfactant concentrations. This work provided a simple and effective approach to synthesize lamellar mesoporous silicas.

Photo-responsive materials with adjustable self-assembly morphologies and tunable rheological properties have attracted widespread interests of researchers in recent years because of their potential applications in controlled release, microfluidics, sensors, and so forth. In this paper, a series of UV-sensitive anisotropic fluids were prepared by combining trans-ortho-methoxycinnamate (trans-OMCA, in its salts form) and cationic Gemini surfactant propanediyl-α, ω-bis (N-dodecyl-N, N-dimethylammonium bromide) (12-3-12·2Br−) based on the research of self-assembly behaviors of the mixed system. The photo-responsive behaviors of anisotropic fluid formed in 12-3-12·2Br−/trans-OMCA/H2O system including macroscopic phase transition, microstructure transformation, rheological property, molecular interaction and isomerization degree of trans-OMCA were investigated by various techniques including UV-vis spectrum, rheology measurement, 1H NMR and 2D NOESY spectrum, transmission electron microscopy (TEM), polarized optical microscopy (POM), and dynamic light scattering (DLS). It is proved that upon exposure to UV-light, ortho-methoxycinnamate (OMCA) undergoes a photo-isomerization from trans form to cis form, which results in geometry transitions of the 12-3-12·2Br−/OMCA aggregates accompanied by a continuous phase separation and combination macroscopically; both proportion and concentration of OMCA in anisotropic solution have great influences on the photo-responsive behaviors of the system including the durations of UV irradiation and isomerization degrees of OMCA at the phase transition points. The photo-responsiveness of this smart fluids and the quantitative analysis are expected to provide reference for academic research or practical application in the fields of biomedicine, soft matters, food engineering and sunscreen.

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Photoresponsive systems with adjustable self-assembly morphologies and tunable rheological properties have aroused widespread concern of researchers in recent years because of their prospect applications in controlled release, microfluidics, sensors, and so forth. In this paper, we combine a cationic Gemini surfactant 12-3-12·2Br

Photoresponsive micellar systems with adjustable aggregate morphologies and rheological properties may be useful in a number of fields such as in microfluidics, controlled release, and sensors. However, the complexity and great difficulty of synthesising photosensitive molecules hamper their practical applications to a significant degree. In this study, we constructed a novel photoinduced self-assembly system by introducing the photoresponsive derivative trans-2-methoxy-cinnamate (trans-OMCA) into the gemini surfactant N,N′-bis(dodecyldimethyl)-1,2-ethane diammonium dibromide (12-2-12·2Br−) solutions. The system displays abundant phase behaviors, and the long worm-like micelles, vesicles, as well as an aqueous two-phase system (ATPS) are observed in the 12-2-12·2Br−/trans-OMCA mixed system even at lower surfactant concentrations. The UV-responsive behavior of the formed vesicles and the worm-like micelles is investigated systematically. The results have shown that OMCA undergoes photoisomerization from the trans-form to the cis-form through UV light irradiation that alters the molecular packing at the micellar interface and thus leads to the transformation of micellar morphologies. The long worm-like micelles will turn into much shorter units when the sample is exposed to 365 nm UV light accompanied by a decrease in solution viscosity by more than an order of magnitude. The formed vesicle system, however, can be utilized to generate a multi-state self-assembly structure, including a worm-like micelle and a small spherical micelle, depending on the UV irradiation time. The morphologies of micelles in a 12-2-12·2Br−/trans-OMCA mixed system can be tailored by adjusting the system composition and the duration of UV light irradiation. Correspondingly, the rheological behavior of the 12-2-12·2Br−/trans-OMCA mixed system can be purposely tuned. The light-induced system with abundant self-assembly behaviors and tunable rheological properties would widen the potential application of gemini surfactants in drug delivery, smart fluids, and materials science.

The properties and extraction for [Ni(NH3)6]2+ of anionic aqueous two-phase systems (ATPS-a) that formed in mixtures of cetyltrimethylammonium bromide (CTAB) and excess sodium dodecyl sulfate (SDS) aqueous solutions were investigated. The results showed that the properties and extraction effects were strongly affected by the surfactant concentration, the temperature of system, and the mole fraction of surfactants. The increase of temperature induces narrower phase region and larger phase volume ratio. In addition, [Ni(NH3)6]2+ was extracted into the surfactant-rich phase with higher distribution coefficient when the liquid crystal had the birefringent properties. Moreover, the distribution coefficient can be improved through reducing the concentration of surfactant from 0.15 to 0.05 mol · L−1 or increasing mole fraction of CTAB from 21.9% to 23.1%. The results showed that ATPS of cationic–anionic surfactants was efficient for [Ni(NH3)6]2+ extraction with distribution coefficients of 13.5 when the total su...

Cyclic voltammetry method was used to investigate the dispersal behaviors of micelles in mixed solutions of cationic surfactant CTAB (cetyltrimethyl ammonium bromide) and anionic surfactant SDS (sodium dodecyl sulfate) at 313 K using ferrocene as the probe. Voltammetric behaviors of ferrocene on the electrode were reversible, indicating the diffusion of ferrocene in the mixtures of cationic and anionic surfactants was controlled by the microstructures of the mixtures. The results showed that the anionic micellar diffusion coefficient initially decreased and then increased with CTAB content due to the structural transformation of micelles. However, the cationic micellar diffusion coefficient curve appeared a monotonous decreasing trend with the increase of the CTAB content in the experimental range, and the diffusion coefficient of cationic micelle was smaller than that of anionic micelle.

This study demonstrated a generic and simple approach to generate durable antibacterial ability on cellulose without using covalently bonding tethering groups that limit the structure design. CO2-philic silicone with quaternary ammonium salt (QAS) pendants was synthesized through hydrosilylation reaction of poly(methylhydrosiloxane) (PMHS) and 2-(dimethylamino)ethyl acrylate in the presence of platinum-based catalyst and subsequent quaternization with 1-bromohexane. The resultant QAS silicone was deposited onto cellulose by adsorption from supercritical CO2 (scCO2) to provide potent biocidal activities against Staphylococcus aureus and Escherichia coli. Presented data also showed that the antibacterial layer was very stable toward washing and UV irradiation owning to the low surface tension and relatively high bond energy of the backbone of silicone. This procedure is applicable to substrates of other shape and chemistry.

The phase behaviors and properties of alkyl trimethyl ammonium bromide with different carbon-chain length/sodium dodecyl sulfate (SDS)/NaBr/H2O systems at the total surfactant concentration of 0.1 mol · L−1 at 333 K were investigated. The experimental results indicate that the phase behaviors of different systems have similar distributing rules. The carbon-chain length of cationic surfactant can influence the position of aqueous two-phase system region, especially for aqueous two-phase system with cationic surfactant in excess, but only have slight effect on aqueous two-phase system with anionic surfactant in excess. The ATPSc region narrows as the length of carbon-chain increases, while the trend for ATPSa is opposite. Increasing the carbon-chain length to some extent will be favorable to shortening the formation time of ATPS greatly. The investigations illustrate that the above rules result from a hydrophobic interaction relationship between surfactant molecules.

Aqueous two-phase systems (ATPS) are formed in mixtures of sodium dodecylsulfate (SDS), cetyltrimethyl ammonium bromide (CTAB), and sodium bromide (NaBr). Two different kinds of ATPS appear when CTAB and SDS surfactants are in excess, respectively. Such ATPS may provide a new, useful partitioning system for separation of bovine serum albumin (BSA). The partitioning of BSA was studied in these systems. The results show that the partitioning is affected by the electrical property, the hydrophobicity and the structure of liquid crystal (LC), which exists in the top phase of the ATPS. BSA is extracted into the top phase with higher distribution coefficient when LC and BSA are oppositely charged. The hydrophobicity of LC, which can be improved by increasing the length of alkyl group, enhances the distribution coefficient. The hydrophobicity of lamellar LC and hexagonal LC is stronger than that of cubic LC, which causes extractive capability of the former is higher than the latter.