Submicron Dispersions of Hexosomes Based on Novel Glycerate Surfactants

2005 ◽  
Vol 58 (9) ◽  
pp. 683 ◽  
Author(s):  
Celesta Fong ◽  
Irena Krodkiewska ◽  
Darrell Wells ◽  
Ben J. Boyd ◽  
James Booth ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Hexagonal Phase ◽  
Phase Behaviour ◽  
Finite Degree ◽  
Micellar Phase ◽  
Subtle Change ◽  
Ambient Temperatures ◽  
New Class ◽  
Cubic Phases ◽  
Excess Water

Glycerate-based surfactants are a new class of swelling amphiphiles which swell to a finite degree with water. Among this class of surfactants, oleyl (cis-octadec-9-enyl) glycerate is very similar in structure to a well characterized mesophase-forming lipid, glyceryl monooleate (GMO). Despite the similar structural characteristics, a subtle change in connectivity of the ester bond substantially alters the binary surfactant–water phase behaviour. Whereas the phase behaviour of GMO is diverse and dominated by cubic phases, the phase behaviour of oleyl glycerate and a terpenoid analogue phytanyl (3,7,11,15-tetramethyl-hexadecane) glycerate is much simplified. Both exhibit an inverse hexagonal phase (HII), which is stable to dilution with excess water, and an inverse micellar phase (LII) at ambient temperatures. The inverse hexagonal phases formed by oleyl glycerate and phytanyl glycerate have been characterized using SAXS. Analogous to GMO cubosomes, the inverse hexagonal phase of phytanyl glycerate has been dispersed to form hexagonally facetted particles, termed hexosomes, whose structure has been verified using cryo-TEM.

scholarly journals Fabrication of Ultrathin MoS2 Nanosheets and Application on Adsorption of Organic Pollutants and Heavy Metals

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 504 ◽  
Author(s):  
Siyi Huang ◽  
Ziyun You ◽  
Yanting Jiang ◽  
Fuxiang Zhang ◽  
Kaiyang Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Electrostatic Interactions ◽  
Large Scale ◽  
Layer Structure ◽  
Structural Characteristics ◽  
Hexagonal Phase ◽  
Two Dimensional ◽  
Mos2 Nanosheets ◽  
Hybrid Strategy ◽  
Ultrathin Mos2 Nanosheets

Owing to their peculiar structural characteristics and potential applications in various fields, the ultrathin MoS2 nanosheets, a typical two-dimensional material, have attracted numerous attentions. In this paper, a hybrid strategy with combination of quenching process and liquid-based exfoliation was employed to fabricate the ultrathin MoS2 nanosheets (MoS2 NS). The obtained MoS2 NS still maintained hexagonal phase (2H-MoS2) and exhibited evident thin layer-structure (1–2 layers) with inconspicuous wrinkle. Besides, the MoS2 NS dispersion showed excellent stability (over 60 days) and high concentration (0.65 ± 0.04 mg mL−1). The MoS2 NS dispersion also displayed evident optical properties, with two characteristic peaks at 615 and 670 nm, and could be quantitatively analyzed with the absorbance at 615 nm in the range of 0.01–0.5 mg mL−1. The adsorption experiments showed that the as-prepared MoS2 NS also exhibited remarkable adsorption performance on the dyes (344.8 and 123.5 mg g−1 of qm for methylene blue and methyl orange, respectively) and heavy metals (185.2, 169.5, and 70.4 mg g−1 of qm for Cd2+, Cu2+, and Ag+). During the adsorption, the main adsorption mechanisms involved the synergism of physical hole-filling effects and electrostatic interactions. This work provided an effective way for the large-scale fabrication of the two-dimensional nanosheets of transition metal dichalcogenides (TMDs) by liquid exfoliation.

scholarly journals Effect of concentration of cadmium sulfate solution on structural, optical and electric properties of Cd1–x Zn x S thin films

2021 ◽  
Vol 42 (11) ◽  
pp. 112101
Author(s):  
Yuming Xue ◽  
Shipeng Zhang ◽  
Dianyou Song ◽  
Liming Zhang ◽  
Xinyu Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Film Growth ◽  
Structural Characteristics ◽  
Hexagonal Phase ◽  
Zinc Content ◽  
Sulfate Concentration ◽  
Cadmium Sulfate

Abstract Cd1– x Zn x S thin films were deposited by chemical bath deposition (CBD) on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film. The SEM results show that the thin film surfaces under the cadmium sulfate concentration of 0.005 M exhibit better compactness and uniformity. The distribution diagrams of thin film elements illustrate the film growth rate changes on the trend of the increase, decrease, and increase with the increase of cadmium sulfate concentration. XRD studies exhibit the crystal structure of the film is the hexagonal phase, and there are obvious diffraction peaks and better crystallinity when the concentration is 0.005 M. Spectrophotometer test results demonstrate that the relationship between zinc content x and optical band gap value E g can be expressed by the equation E g(x) = 0.59x 2 + 0.69x + 2.43. Increasing the zinc content can increase the optical band gap, and the absorbance of the thin film can be improved by decreasing the cadmium sulfate concentration, however, all of them have good transmittance. At a concentration of 0.005 M, the thin film has good absorbance in the 300–800 nm range, 80% transmittance, and band gap value of 3.24 eV, which is suitable for use as a buffer layer for solar cells.

Influence of Dodecyltrimethylammonium Halides on Interaction of Phenyltin Compounds with Model Membranes

2001 ◽  
Vol 56 (7-8) ◽  
pp. 623-628
Author(s):  
Bożenna Różycka-Roszak ◽  
Hanna Pruchnik
Keyword(s):  
Phase Formation ◽  
Nmr Spectra ◽  
Structural Changes ◽  
Hexagonal Phase ◽  
Model Membranes ◽  
Phase Behaviour ◽  
Dodecyltrimethylammonium Bromide ◽  
H Nmr ◽  
Dodecyltrimethylammonium Chloride ◽  
Triphenyltin Chloride

The effects were studied of dodecyltrimethylammonium chloride (DTAC), dodecyltrimethylammonium bromide (DTAB) and dodecyltrimethylammonium iodide (DTAI) on thermo­tropic phase behaviour of phosphatidylcholine bilayers, as well as on 1H NMR and 31P NMR spectra, in the presence of diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT). The obtained results indicate that in the presence of the surfactant studied the interaction of phenyltin compounds with model membranes was changed and the changes depended on the kind of the counterion. The surfactants studied (especially DTAC) decrease the ability of phenyltin compounds to induce structural changes in the bilayer. It is suggested that DTAB, and especially DTAC, prevent DPhT induced interdigitated phase formation as well as formation of an inverted hexagonal phase (HII) in the case of TPhT/DPPC liposomes

scholarly journals Aqueous biphasic systems formed in (zwitterionic salt+inorganic salt) mixtures

2019 ◽  
Vol 91 (8) ◽  
pp. 1351-1360 ◽  
Author(s):  
Jordan Mills ◽  
Gaelle Level ◽  
Chirangano Mangwandi ◽  
Marijana Blesic
Keyword(s):  
Ternary Phase ◽  
Inorganic Salt ◽  
Phase Behaviour ◽  
Aqueous Biphasic Systems ◽  
Aromatic Molecules ◽  
New Class ◽  
Ternary Phase Diagrams ◽  
Salt Mixtures ◽  
Aqueous Biphasic ◽  
Biphasic Systems

Abstract The manuscript reports on a new class of aqueous biphasic systems (ABSs) formed in mixtures of inorganic salts (ISs) and zwitterionic salts (ZWSs). Aqueous ternary phase diagrams characterized by a binodal curve were determined for systems consisting of four ISs, K3PO4, K2HPO4, K2HPO4/KH2PO4, and K2CO3, and three structurally similar ZWSs differing in hydrophobicity. Comparison of phase behaviour of ABSs composed of ZWSs, ionic liquids (ILs) and zwitterions was provided. Potential of ZWSs based systems for extraction of aromatic molecules and amino acids, such as glycine, L-tryptophan, DL-phenylalanine, eugenol, and phenol was examined. Feasibility and limitations of isolation of products after partition and recovery of ZWS were discussed.

The phase behaviour of lipid X at high water concentration

1990 ◽  
Vol 68 (1) ◽  
pp. 345-351 ◽  
Author(s):  
G. Lipka ◽  
H. Hauser
Keyword(s):  
Differential Scanning Calorimetry ◽  
Hexagonal Phase ◽  
Water Concentration ◽  
Critical Micellar Concentration ◽  
High Water ◽  
Phase Behaviour ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Repeat Distance ◽  
X Ray

The phase behaviour of lipid X at high water concentrations (> 60%) is studied using mainly differential scanning calorimetry (DSC) and X-ray diffraction. The critical micellar concentration (CMC) decreases from 8 × 10−5 M at −2 °C to 4 × 10−5 M at 20 °C. The critical micellar temperature (CMT) is 0 °C and decreases slightly with increasing lipid X concentration. Above the CMC and below the CMT, lipid X forms a lamellar gel phase (Lβ). Above 0 °C and at concentrations ranging from the CMC up to about 0.2 M (20%), lipid X forms small micelles. At even higher concentrations there is a transition to a hexagonal phase, probably hexagonal I. Addition of excess NaCl to lipid X dispersions at concentrations < 0.2 M (20%) has several effects on the phase behaviour of lipid X. (i) The lamellar phase is stabilized up to temperatures of ≈20 °C at [NaCl] ≥ 0.7 M. (ii) NaCl induces a tighter packing of the hydrocarbon chains. (iii) At concentrations > 0.7 M NaCl, the bilayer repeat distance decreases to about 43 Å (1 Å = 0.1 nm).Key words: lipid X, phase behaviour, effects of NaCl, differential scanning calorimetry, X-ray diffraction.

scholarly journals Aqueous phase behaviour of choline carboxylate surfactants—exceptional variety and extent of cubic phases

Soft Matter ◽  
2011 ◽  
Vol 7 (15) ◽  
pp. 6973 ◽  
Author(s):  
Regina Klein ◽  
Gordon J. T. Tiddy ◽  
Eva Maurer ◽  
Didier Touraud ◽  
Jordi Esquena ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Phase Behaviour ◽  
Cubic Phases

Cubic phases of self-assembled amphiphilic aggregates

1993 ◽  
Vol 344 (1672) ◽  
pp. 377-401 ◽  
Keyword(s):  
Liquid Crystalline ◽  
Hexagonal Phase ◽  
Hydrocarbon Chain ◽  
Planar Geometry ◽  
Cubic Phase ◽  
Stress Profile ◽  
Cubic Phases ◽  
Lamellar Phases ◽  
Micellar Aggregates ◽  
Normal Topology

In this paper we give an overview of cubic liquid-crystalline mesophases formed by amphiphiles. In § 1 we present brief descriptions of the principal types of translationally ordered lyotropic phases, and describe the locations in the phase diagrams where the different types of cubic phase occur. In §2 we discuss the various forces that act between bilayers. These transverse interactions are relatively straightforward to quantify in the case of lamellar phases, but are more complex for cubic phases, because of the non-planar geometry. In §3 we show how an intrinsic desire for interfacial curvature can lead to a state of physical frustration. We then introduce the curvature elastic energy, and describe how this may be related to the stress profile across the bilayer. In the following sections we focus attention on the inverse (water-in-oil) versions of the non-lamellar phases, although analogous effects also operate in the normal topology (oil-in-water) structures. In §4 we briefly describe the inverse hexagonal phase, which is the simplest inverse phase with curved interfaces. This allows us to illustrate the role of hydrocarbon chain packing frustration in a rather clear way before coming on to the more subtle interplay between packing and curvature frustration, characteristic of the bicontinuous cubic phases, which is discussed in §5. In §6 we describe an entirely different class of cubic phases, with positive interfacial gaussian curvature. These cubic phases are composed of complex packings of discrete micellar or inverse micellar aggregates, which may be quasi-spherical and/or anisotropic in shape. Finally, in §7 we discuss geometric aspects of transitions between lamellar, hexagonal and cubic phases, and show how determination of the epitaxial relations between phases can shed light on the precise mechanisms of the phase transitions.

scholarly journals Unique Digoldgermanes: Structural Characteristics, Dynamic Behaviour and Distinctive Reactions

2021 ◽  
Author(s):  
Liliang Wang ◽  
Guorong Zhen ◽  
Yinhuan Li ◽  
Mitsuo Kira ◽  
Liping Yan ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Dynamic Behaviour ◽  
Structural Characteristics ◽  
Bond Formation ◽  
Gold Atom ◽  
Addition Product ◽  
X Ray ◽  
Ambient Temperatures ◽  
X Ray Crystallography ◽  
H Nmr

Abstract Digoldgermanes with a gold coordinated by a dialkylgermylene ligand, R’2Ge(AuPR3)(AuGeR’2) (3a; R = Me, 3b; R = Et), were synthesized as green solids through the reactions of stable dialkylgermylene 1 with R3PAuCl followed by the reduction with KC8 at ambient temperatures. The structural characteristics of 3a and 3b were elucidated using NMR spectroscopy, X-ray crystallography, and DFT calculations. An intense absorption maximum was observed at 590 nm in the UV-vis spectrum of 3a in hexane. A pendular motion of AuPR3 group between Ge(IV) and Ge(II) of 3a and 3b occurring in the NMR time scale was found by the dynamic 1H NMR analysis, suggesting that the Ge(II) ligand has an enhanced electrophilicity to be attacked by the nucleophilic gold atom which closes to ‒1 oxidation state. DFT calculations of 3a revealed the existence of high-lying σ(Ge-Au) type HOMO and low-lying LUMO with germylene pπ nature. We show the bond formation and activation alternatively at Au or Ge atom, a methylation of digoldgermane 3a with MeOTf affords methylgermane 5. Moreover, the digoldgermane 3a reacts with Cl− ion of Ph4PCl and CH3C(O)Cl smoothly to form the corresponding chloride-addition product 7 and chlorogoldgermane 9, respectively. Cyclic trimerization reactions of aromatic isocyanates were high-efficiently catalyzed by 3a giving the corresponding 1,3,5-triaryl isocyanurates.

scholarly journals Three-dimensional periodic complex structures in soft matter: investigation using scattering methods

2012 ◽  
Vol 2 (5) ◽  
pp. 589-601 ◽  
Author(s):  
Marianne Impéror-Clerc
Keyword(s):  
Soft Matter ◽  
Hexagonal Phase ◽  
Three Dimensional ◽  
Structural Models ◽  
Close Packing ◽  
Complex Structures ◽  
Structured Materials ◽  
X Ray ◽  
X Ray Scattering ◽  
Cubic Phases

Three-dimensional periodic complex structures are encountered in various soft matter systems such as liquid crystals, block-copolymer phases and the related nano-structured materials. Here, we review several well-defined topologies: two-dimensional hexagonal phase, three-dimensional packing of spheres, tetrahedral close packing ( tcp ) bi-continuous and tri-continuous cubic phases. We illustrate how small-angle X-ray scattering experiments help us to investigate these different structures and introduce the main available structural models based on both direct and inverse methods.

STRUCTURAL CHARACTERISTICS OF La2O3 THIN FILM GROWN ON LaB6

2012 ◽  
Vol 15 ◽  
pp. 61-66 ◽  
Author(s):  
Y. A. KAFADARYAN ◽  
S. I. PETROSYAN ◽  
G. R. BADALYAN ◽  
V. G. LAZARYAN ◽  
G. H. SHIRINYAN ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Lanthanum Oxide ◽  
Annealing Temperature ◽  
Structural Characteristics ◽  
Hexagonal Phase ◽  
Lanthanum Hexaboride ◽  
Air Pressure ◽  
X Ray ◽  
Different Temperatures ◽  
Structure Versus

Within the framework of hexagonal lanthanum oxide ( h - La 2 O 3) formation, lanthanum hexaboride film on sapphire substrate ( LaB 6/ Al 2 O 3) was oxidized at different temperatures (700-1000 °C) under reduced atmospheric pressure (1·10-2,1.5·10-1Torr) during 30 min. The composition evolution of La 2 O 3/ LaB 6 structure versus annealing temperature has been studied using XRD, FIR reflectivity spectroscopy, SEM and electron probe X-ray microanalysis (EDS). The annealing of the LaB 6 film at T =700 °C under air pressure of 1·10-2 Torr generates thin La 2 O 3 layer which exhibits as inferred from XRD the hexagonal phase. The hydratation of La 2 O 3/ LaB 6/ Al 2 O 3 in distilled water for 30 min and postannealing at 900 °C under air pressure of 1.5·10-1 Torr transform h - La 2 O 3 into hexagonal La ( OH )3 phase accompanied monoclinic LaO ( OH ) and lanthanum oxide carbonate hydrate species.

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