ABSTRACT Combining excellent electrical properties, high surface area, and mechanical properties of single‐wall carbon nanotubes (SWCNTs) via a surfactant‐free method into a robust film electrode is challenging for energy applications. Here, we report free‐standing SWCNT films derived with the aid of a Zn/Al complex dispersant with electrical conductivity as high as 5.5 × 10 5 S m −1 , surface area as high as 1200 m 2 g −1 , and tensile strength of 300 MPa, that are promising for dispersed Pt nanoparticle support in fuel cells. The free‐standing Pt/SWCNT film electrode shows fuel cell activity and a drop of −5.4% in electrochemical surface area (ECSA) after 10 000 accelerated durability test (ADT) cycles, which is superior to graphene and commercial carbon supports. The electronic state of Pt on the SWCNTs was not changed during fuel cell operation at an anodic and cathodic potential scan of 0.4 – 1.0 V, as evidenced by operando X‐ray absorption fine structure (XAFS) spectroscopy. The free‐standing SWCNT films prepared from the SWCNT surfactant‐free inks offer possibilities for fuel cell electrode preparation.

The surface chemical properties and phase behaviors of the three acid-base 2:1 complexes were systematically studied. It was composed of tertiary amine as the main chain and three dicarboxylic acids as the spacer and functioned as a gemini-type surfactant. N-methyl-N-(2,3-dioxypropyl)hexadecylamine (C16amine) was used as the main chain, and octanoic acid (C8), decanoic acid (C10), and dodecanoic acid (C12) were combined to form complexes. In dilute solutions, the surface tension and luminescence behaviors of solubilized pyrene were consistent across all three complexes, indicating similar micellar characteristics at lower concentrations. However, the concentrated complexes clearly showed different behaviors. In the case of complexes composed of C16amine and C8 or C16amine and C10, as the concentration increased, hexagonal, bicontinuous, and lamellar phases were observed. For the complex composed of C16amine and C12, the hexagonal phase was not observed. This deviation in phase behavior is assumed to arise from the folding structure of the alkyl chain in the dicarboxylic acid. The folding structure may influence the packing structure of the liquid crystal phases, thereby altering the phase formation.

The main purpose of the current study was to employ filtration pretreatment to lower the K concentration in distillery wastewater (DW) from a very high level (8800 mg/L) close to severe inhibition (>12000 mg/L) to 4350 mg/L, which was in the moderate toxic range (2500-4500 mg/L) for methanogens. The filtration pretreatment system consisted of the two steps of microfiltration (MF) to remove large solid particles and nanofiltration (NF) to reduce K concentration in the retained DW. Both steps of MF and NF were operated in batch mode with continuous recirculation. The permeate of the MF step was fed to the NF unit in conjunction with different dilution ratios (dilution water volume-to-feed volume) to lower the K content in the retentate. The higher the cumulative dilution ratio, the lower the K concentration in the retentate of the NF step. However, it has to be traded off against the increasing total volume of permeate with the higher cumulative dilution ratio. Thus, at the optimum cumulative dilution ratio of 0.5:1, the DW from filtration pretreatment with a high COD value of 111500 mg/L and a low K content of 4350 mg/L was found to have significantly higher methanogenic productivities in terms of average production rate and yields of both biogas and methane with a higher optimum COD loading rate, as compared to those of the untreated DW. Moreover, the use of the two-step filtration in this investigation could significantly lower the dilution ratio as compared to the sole dilution method (0.5:1 against 2:1).

The polyol dilution (PD) method is an approach for preparing liposomes by pre-mixing a lipid/polyol binary mixture, followed by hydration, and is widely used in the cosmetics industry. In this method, polyols play an important role in the formulation design and application, however, the effect of the polyol type on liposomes (PD-liposomes) is yet to be understood. In this study, we investigated the effect of three types of polyols—glycerol (Gly), propylene glycol (PG), and 1,3-butylene glycol (BG)—on the physicochemical properties of PD-liposomes composed of hydrogenated egg yolk lecithin (EL). The particle size of PD-liposomes was controlled by adjusting the type and concentration of the polyols. Furthermore, the addition of polyols improved the dispersion stability, indicating that PD-liposomes are suitable for industrial applications. The morphology of lipid/polyol binary mixture was the determining factor of the liposome structure, and the formation region of unilamellar vesicles (ULVs) and multilamellar vesicles (MLVs) was closely related to the dielectric constant of the dispersion medium. ULVs were formed using a high dielectric constant dispersion medium, such as Gly, and MLVs were formed using a low dielectric constant dispersion medium, such as PG and BG at high concentrations. This study showed that the addition of polyols improves the phase homogeneity of the bilayer and that PG or BG is more effective than Gly. The control of the homogeneity of the bilayer phase is an effective technique to prevent leakage and control the sustained release of the active ingredient; thus, this method enhances the efficacy of the active ingredient. This study is the first to systematically elucidate the control mechanisms of the physicochemical properties of PD-liposomes, including the particle size, dispersion stability, shape, and phase state of the bilayer. Our findings will contribute to the wide range of applications of PD-liposomes.

Liposomes, which are formed from phospholipids, have been widely applied in cosmetics for skin enhancement. The polyol dilution (PD) method is commonly used to prepare liposomes in the cosmetic industry. An under-standing of liposome physicochemical properties is essential for cosmetic-formulation design and application. However, there have been few studies on the characterization of liposomes prepared by the PD method (PD-liposomes). Here, we studied the effect of 1,3-butylene glycol (BG) on the formation of egg-yolk lecithin (EL) -based PD-liposomes. Furthermore, the use of BG to control the liposome structural and membrane properties was investigated. The use of BG enables particle-size control of liposomes and improves the dispersion stability. In the preparation of PD-liposomes, the structure of the molecular assembly in the EL/BG binary system prior to hy-dration is an important factor in determining the type of PD-liposome produced. The key step in the preparation of unilamellar and multilamellar vesicles is the formation of spherical vesicles with low BG concentrations, or a stacked planar lamellar structure with high BG concentrations in the EL/BG binary system followed by hydration to form liposomes, respectively. Various properties of liposomes can be readily controlled by changing the polyol concentration. Therefore, the PD method is superior to the conventional method not only in terms of process advantages such as simplicity, ability to achieve mass production, and the absence of toxic organic solvents, but also in terms of suitability for industrial applications.

This study aimed to evaluate the membrane structure of distearoylphosphatidylcholine (DSPC) liposomes dispersed in water containing various types of polyols with low molecular weight such as glycerin (Gly), 1,3-butandiol (BG), and propylene glycol (PG). To clarify the detailed membrane structure, generalized indirect Fourier transformation (GIFT) analysis, which provides information about the bilayer spacing, bilayer thickness, number of lamellar layers, and membrane flexibility, was applied to small-angle X-ray scattering (SAXS) data of the present system. The GIFT results showed that the bilayer thickness of the DSPC liposomes followed the order Gly>>BG>PG. In addition, the membrane flexibility estimated by the Caille parameter was in the order Gly>>BG>PG; this result was supported by the gel-liquid crystal phase transition temperature (Tc) obtained by differential scanning calorimetry (DSC). These results, together with the Raman spectra, suggest that BG and PG incorporated into the bilayers of DSPC liposomes result in the formation of an interdigitated lamellar structure.

Plants of the Meliaceae family have been well documented for their ability to metabolize structurally diverse and biologically significant limonoids. To search for potential bioactive compounds from Meliaceae plants, we have investigated the limonoids and other secondary metabolites of Azadirachta indica A. Juss. (AI; neem tree) and Azadirachta indica A. Juss. var. siamensis Valeton (AIS; Siamese neem tree), and have isolated and characterized 81 limonoids, 1 diterpenoid, and 11 flavonoids. These compounds have been demonstrated potent bioactivities, including melanogenesis-inhibitory activity in B16 melanoma cells, inhibitory potential against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced Epstein–Barr virus early antigen (EBV-EA) activation, a primary screening for inhibitors of tumor promotion, cytotoxic activities against human cancer cell lines, inhibitory activity against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells, a primary screening for antiinflammatory agents, and antiinflammatory activity against TPA-induced inflammation in mice. In this review chapter, isolation, characterization, and bioactivities, including melanogenesis-inhibitory activity, cancer chemopreventive property, cytotoxic activity, and antiinflammatory activity, of limonoids and other secondary metabolites of AI and AIS, which are mostly the results of our investigations are presented.

The interaction of copolymer L61 i.e., (EO)2(PO)32(EO)2 (where EO and PO are ethylene and propylene oxides, respectively) with surfactant SDS (sodium dodecylsulfate) in relation to their self-aggregation, dynamics and microstructures has been physicochemically studied in detail employing the Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR), Small-Angle Neutron Scattering (SANS), and Freeze-Fracture Transmission Electron Microscopy (FF-TEM) methods. The NMR self-diffusion study indicated a synergistic interaction between SDS and L61 forming L61-SDS mixed complex aggregates, and deuterium (2H) NMR pointed out the nonspherical nature of these aggregates with increasing [L61]. EPR spectral analysis of the motional parameters of 5-doxyl steraric acid (5-DSA) as a spin probe provided information on the microviscosity of the local environment of the L61-SDS complex aggregates. SANS probed the geometrical aspects of the SDS-L61 assemblies as a function of both [L61] and [SDS]. Progressive evolution of the mixed-aggregate geometries from globular to prolate ellipsoids with axial ratios ranging from 2 to 10 with increasing [L61] was found. Such morphological changes were further corroborated with the results of 2H NMR and FF-TEM measurements. The strategy of the measurements, and data analysis for a concerted conclusion have been presented.

For simple removal of saturated fatty acid methyl esters (FAMEs) from a FAME mixture, our previous research described winterization using sorbitan palmitate without agitation. However, limited information exists on additive winterization of real oil biodiesels and their separation performance. We demonstrated the additive winterization of biodiesel fuel derived from commercial eatable oils and fat (palm, lard, cottonseed, rice, and soybean). Five biodiesel fuels were prepared through a transesterification reaction under alkali conditions. The biodiesel-additive mixtures were air-cooled over 48 h at a temperature equal to or several degrees lower than the cloud point (CP) of the biodiesel without agitation. The palm biodiesel showed a marked similarity to a simulated FAME mixture, and was separated into saturated FAME-rich solid fuel and unsaturated FAME-rich liquid fuel. The CP of the recovered liquid decreased by 6-10.5 degrees C, and the separation factors were between 2.4 and 7.7. The kinetic viscosity of the resultant liquid increased slightly because of the oleate fraction but was in the range of the biodiesel standard. These results indicate that additive winterization is useful for the separation and purification of biodiesel. Because the separation factor of the lard biodiesel winterization using sorbitan palmitate decreased (1.3-1.9), the separation improver retains scope for improvement under high stearate conditions. The relatively lower saturated FAME biodiesels (cottonseed, rice, and soybean) were predisposed to form a slurry during the winterization. However, the CP of the recovery liquid decreased 2-5 degrees C from the initial biodiesels. The separation factor and liquid recovery rate will increase with the use of a proper mechanical separation method such as filtration.

A biomembrane's role is to be a barrier for interior cytosol from an exterior environment to execute the cell's normal biological functions. However, a water-soluble peptide called cell-penetrating peptide (CPP) has been known for its ability to directly penetrate through the biomembranes into cells (cytolysis) without perturbating cell viability and expected to be a promising drug delivery vector. Examples of CPP include peptides with multiple arginine units with strong cationic properties, which is the key to cytolysis. Here we show the conclusive evidence to support the mechanism of CPP's cytolysis and way to control it. The mechanism we proposed is attributed to biomembrane's physicochemical nature as lamellar liquid crystal (Lα). Cytolysis occurs as the temporal and local dynamic phase transitions from Lα to an undulated lamellar with pores called Mesh1. We have shown this phase transfer of Lα composed of dioleoyl-phosphatidylcholine (DOPC) with water by adding oligo-arginine (Rx) as CPP at the equilibrium. Using giant unilamellar vesicle composed of DOPC as a single cell model, we could control the level of cytolysis of CPP (FITC-R8) by changing the curvature of the membrane through osmotic pressure modulation. The cytolysis of CPP utilizes biomembrane's inherent topological and functional flexibility corresponding to the stimuli.

Objective To evaluate the anti-ageing activity of cream containing the methanolic purple glutinous rice extract loaded in niosomes. Methods Thein vitrobiological activities of the purple glutinous rice extracted by methanol maceration were determined. The extract loaded in niosomes and the cream containing the niosomes were developed. Thein vivoanti-ageing activity in 20 human volunteers including skin hydration, pigmentation, roughness and elasticity after daily application for 28 days compared to at initial was evaluated by Corneometer, Mexameter, Visiometer and Cutometer, respectively. Results The purple glutinous rice extract showed free radical scavenging (SC50), lipid peroxidation inhibition (IPC50), metal ion chelating (CC50) and tyrosinase inhibition (IC50) values at 32.31 +/- 1.28, 57.40 +/- 2.12, 85.05 +/- 5.43 and 43.89 +/- 2.14 mg/mL which were 0.00031, 0.011, 0.0078 and 0.0016 times of the standards (0.01 +/- 0.00, 0.62 +/- 0.14, 0.66 +/- 0.05 and 0.07 +/- 0.01), respectively. The purple glutinous rice extract contained 0.35 mu g of anthocyanin/1 mg of the extract determined by HPLC. After loaded in niosomes, the solubility of the extract was not only increased in various solvents, but also the chemical stability in different environments (weak base, reducing agent and acid salt) was improved. The cream formulation containing niosomes loaded with 1%w/v of the purple glutinous rice extract indicated the anthocyanin remaining percentages after 6 cycles of heating and cooling test at 52.28% of the initial. Forin vivoanti-ageing activities, cream containing niosomes loaded with the extract gave significant decreased melanin index and skin roughness reduction of -14.05 and -9.95% of the initial, respectively. The % changes of the increased skin hydration, skin elastic extension and skin elastic recovery when applied on human volunteers' skin with this formulation were +48.73, -24.51 and +35.98%, respectively. Conclusion The cream containing niosomes loaded with the 1%w/v methanolic purple glutinous rice extract gave not only the suitablein vitroantioxidant activity and physical stability of the active anthocyanin, but also the superiorin vivoanti-ageing activity on human skin compared to the cream base and before application which can be further developed as a novel anti-ageing cosmeceutical product.

We studied the phase behavior of a ternary polymerizable gemini surfactant (PC11-6-11)/1-undecanol/water system and stabilized these liquid crystalline structures through the polymerization of surfactants. The addition of 1-undecanol to a PC11-6-11/water system formed bicontinuous cubic (V1) and reversed hexagonal (H2) liquid crystal phases in addition to hexagonal (H1) and lamellar (Lα) phases, which were also formed using the binary system of PC11-6-11/water. These new phases were formed because the fatty alcohol penetrated the palisade layer of the PC11-6-11 micelles. The polymerization of PC11-6-11 with a thermal initiator successfully preserved the Lα and H2 phases. Layered or honeycomb structures of these liquid crystals were clearly observed by transmission electron microscopy. The nanomaterials have potential applications as membranes for nano- or microfiltration and catalyst support materials.

Surfactants are active or essential ingredient of several industrial and consumer formulations. These amphiphilic organic molecules demonstrate unique ability to adsorb at the interface and self-aggregate or self-assemble into different phases in aqueous or nonaqueous solution. In recent years, environmental concerns coupled with increased consumer awareness have guided substantial growth of environmentally benign surfactant molecules often termed as ‘green surfactants’, oleochemical-based surfactants', ‘renewable surfactants’ ‘biosurfactants’, ‘natural surfactants’, and so on. These groups of new generation of eco-friendly surfactant molecules often directly or indirectly derived/developed from renewable building blocks can be broadly termed as ‘sustainable surfactants’ which are increasingly becoming popular in many application areas. The ever-increasing demand of surfactants in several application areas necessitates development of many new structural analogs of these molecules by sustainable approach. This review summarizes recent progress in the area of sustainable surfactants, their potential impact, and future perspective.

The effects of additive structure on the separation of saturated fatty acid methyl esters (FAMEs) from FAME mixtures by winterization were investigated. Six sorbitan derivatives, seven palmitate derivatives, and sorbitan monopalmitate, which is known to improve the low-temperature separation of FAME mixtures, were studied. A model FAME mixture was prepared by blending saturated FAME (methyl palmitate) and unsaturated FAME (methyl oleate). Sorbitan derivatives that had fatty-acid groups with the same carbon chain length as the main saturated FAME in the FAME mixture improved the separation significantly. Shorter chain lengths and unsaturated fatty acid groups did not promote the winterization of FAME mixtures because their interactions with the main saturated FAME were too weak. Cyclic structures and hydroxy (OH) groups in the ester groups of the palmitate derivatives were found to be essential for preventing crystal growth and liquid contamination of the recovered solid phase. Cyclic structures affected the appearance of the FAME mixture during winterization, and the presence of OH groups affected the separation factor and the cloud point (CP) of the recovered liquid FAME. Span40, which has palmitate and sorbitan groups, was found to be the most effective additive for mixtures containing approximately 50 wt% methyl palmitate. The CP of the recovered liquid decreased 4-9 K, and the separation factors were between 3.6 and 7.5. These results will be useful for the separation and purification of saturated rich-FAME mixture such as palm, lard, mahua, neem, and jatropha biodiesels.

A specific series of peptides, called a cell-penetrating peptide (CPP), is known to be free to directly permeate through cell membranes into the cytosol (cytolysis); hence, this CPP would be a potent carrier for a drug delivery system (DDS). Previously, we proposed the mechanism of cytolysis as a temporal and local phase transfer of membrane lipid caused by positive membrane curvature generation. Moreover, we showed how to control the CPP cytolysis. Here, we investigate the phospholipid vesicle’s size effect on CPP cytolysis because this is the most straightforward way to control membrane curvature. Contrary to our expectation, we found that the smaller the vesicle diameter (meaning a higher membrane curvature), the more cytolysis was suppressed. Such controversial findings led us to seek the reason for the unexpected results, and we ended up finding out that the mobility of membrane lipids as a liquid crystal is the key to cytolysis. As a result, we could explain the cause of cytolysis suppression by reducing the vesicle size (because of the restriction of lipid mobility); osmotic pressure reduction to enhance positive curvature generation works as long as the membrane is mobile enough to modulate the local structure. Taking all the revealed vital factors and their effects as a tool, we will further explore how to control CPP cytolysis for developing a DDS system combined with appropriate cargo selection to be tagged with CPPs.

New ester functionalized branched anionic surfactant-sodium citronellyl sulfoacetate (SCSA) is developed from naturally occurring acyclic monoterpene citronellol. This new surfactant is investigated for its self-aggregation, detergent, and biodegradation properties. Surface properties of the SCSA are determined by surface tension and conductivity method. Hydrodynamic radius of the micelles formed by the new surfactant is determined by dynamic light scattering technique. Detergency and foaming properties of the new surfactant are determined by Tergotometer and Ross-Miles method respectively. Further, the biodegradation property of the SCSA was determined by the BOD method. The experimental evaluation result establishes SCSA to be a good sustainable alternative to petrochemical derived surfactants. The new surfactant demonstrated good surface activity along with excellent detergent and biodegradation properties.

Cell-penetrating peptide (CPP) can directly penetrate the cytosol (cytolysis) and is expected to be a potent vector for a drug delivery system (DDS). Although there is general agreement that CPP cytolysis is related to dynamic membrane deformation, a distinctive process has yet to be established. Here, we report the key process and factors controlling CPP cytolysis. To elucidate the task, we have introduced trypsin digestion of adsorbed CPP onto giant unilamellar vesicle (GUV) to quantify the adsorption and internalization (cytolysis) separately. Also, the time-course analysis was introduced for the geometric calculation of adsorption and internalization amount per lipid molecule consisting of GUV. As a result, we found that adsorption and internalization assumed to occur successively by CPP molecule come into contact with membrane lipid. Adsorption is quick to saturate within 10 min, while cytolysis of each CPP on the membrane follows successively. After adsorption is saturated, cytolysis proceeds further linearly by time with a different rate constant that is dependent on the osmotic pressure. We also found that temperature and lipid composition influence cytolysis by modulating lipid mobility. The electrolyte in the outer media is also affected as a chemical mediator to control CPP cytolysis by following the Hoffmeister effect for membrane hydration. These results confirmed the mechanism of cytolysis as temporal and local phase transfer of membrane lipid from Lα to Mesh1, which has punctured bilayer morphologies.

Ester based anionic surfactant—sodium lauryl sulfoacetate (SLSA)—is one of the most important surface-active ingredients in several personal care products however no scientific report is available regarding its lyotropic and thermotropic phase behavior in water. In the present study, SLSA and its congener sodium myristyl sulfoacetate (SMSA) are investigated for their self-aggregation properties in aqueous system. Phase transition temperature of these surfactant–water mixtures is determined by differential scanning calorimetry (DSC). Their lyotropic and thermotropic phase behavior in water are investigated by polarized optical microscopy (POM), small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS). These surfactants predominantly exist as different types of self-assembled lamellar phases along with or without solid crystalline phases in aqueous system.