scholarly journals Highly concentrated emulsion with a cubic liquid crystal as the external phase: characterization and obtaining of meso/macroporous material

2013 ◽  
Vol 30 ◽  
pp. 87-96 ◽  
Author(s):  
E. Santamaría ◽  
M. Cortés ◽  
A. Maestro ◽  
M. Porras ◽  
J. M. Gutiérrez ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Droplet Size ◽  
Raw Materials ◽  
Water System ◽  
Chemical Society ◽  
Continuous Phase ◽  
Rheological Parameters ◽  
Macroporous Material ◽  
Internal Phase ◽  
External Phase

High internal phase ratio emulsions (HIPRE) or highly concentrated emulsions are characterized by their large internal phase volume.The nature and concentration of surfactant affects several features of the final emulsion, such as stability, droplet size and structure of the external phase. Therefore, an ordered external mesophase (structure of liquid crystal) can be obtained. The present work studies the influence of composition and preparation variables on the final properties of HIPRE with an external phase formed by a bicontinuous cubic liquid crystal. The studied outputs variables were droplet size, stability and rheological parameters as yield stress, viscosity at a fixed shear rate and the plateau value of the storage modulus. O/W HIPREs were prepared with a decane/brij 35/water system. Once the emulsions were characterized the meso/macroporous material was obtained. In order to prepare the materials, the emulsions were formed by incorporating the catalyst of the reaction (HCl) in the continuous phase. When the emulsions were formed, tetraethylorthosilicate (TEOS) was added as a silica source In order to optimize the production process a study of reutilization and recovery of some of the raw materials (i.e: the surfactant and the EtOH used) was done.DOI: http://dx.doi.org/10.3126/jncs.v30i0.9374Journal of Nepal Chemical Society Vol. 30, 2012 Page:  87-96 Uploaded date: 12/19/2013   

Water and Oil Dual-Absorption Composite Resins Prepared from High Internal Phase Emulsion

2014 ◽  
Vol 884-885 ◽  
pp. 186-189 ◽  
Author(s):  
San Zhu ◽  
Xiao Gang Luo ◽  
Li Bin Ma ◽  
Ya Nan Xue ◽  
Ning Cai ◽  
...  
Keyword(s):  
Composite Resins ◽  
Butyl Methacrylate ◽  
Oil Uptake ◽  
Absorption Properties ◽  
High Internal Phase Emulsion ◽  
Saturated Water ◽  
Internal Phase ◽  
External Phase ◽  
Potential Applications ◽  
Scanning Electron

Novel composite resins with dual absorption properties of water and oil are prepared by the polymerization of high internal phase emulsion (HIPEs) with n-butyl methacrylate as the external phase monomer and acrylamide as the internal phase monomer. The subsequent polymerization leads to the formation of water and oil dual-absorption composite resins. The morphology of porous structure and microcosmic phase separation after water/oil uptake is observed by scanning electron microscopy (SEM). The water and oil absorbency strongly depend on composition. The composites with saturated water uptake could absorb the chloroform again but cant absorb water if saturated with chloroform first. And the resins exhibit great reusability, keeping almost constant absorbency. The present methodology could be a potential approach to obtain amphiphilic composites, which possess potential applications in the bioengineering, medical and industrial fields.

Effect of Shear and Water Cut on Phase Inversion and Droplet Size Distribution in Oil–Water Flow

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Mo Zhang ◽  
Ramin Dabirian ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Phase Inversion ◽  
Droplet Size Distribution ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Water Emulsion ◽  
Inversion Region ◽  
Oil Water ◽  
Water Cut

Oil–water dispersed flow occurs commonly in the petroleum industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties, and other factors. Production equipment, such as pumps and chokes, generates shear in oil–water mixture flow, which has a strong effect on phase inversion phenomena. The objective of this paper is to investigate the effects of shear intensity and water cut (WC) on the phase inversion region and also the droplet size distribution. A state-of-the-art closed-loop two phase (oil–water) flow facility including a multipass gear pump and a differential dielectric sensor (DDS) is used to identify the phase inversion region. Also, the facility utilizes an in-line droplet size analyzer (a high speed camera), to record real-time videos of oil–water emulsion to determine the droplet size distribution. The experimental data for phase inversion confirm that as shear intensity increases, the phase inversion occurs at relatively higher dispersed phase fractions. Also the data show that oil-in-water emulsion requires larger dispersed phase volumetric fraction for phase inversion as compared with that of water-in-oil emulsion under the same shear intensity conditions. Experiments for droplet size distribution confirm that larger droplets are obtained for the water continuous phase, and increasing the dispersed phase volume fraction leads to the creation of larger droplets.

Haematite–water system on Mars and its possible role in chemical evolution

2007 ◽  
Vol 6 (4) ◽  
pp. 267-271 ◽  
Author(s):  
Avnish Kumar Arora ◽  
Varsha Tomar ◽  
Aarti ◽  
K.T. Venkateswararao ◽  
Kamaluddin
Keyword(s):  
Chemical Evolution ◽  
Water System ◽  
American Chemical Society ◽  
Building Blocks ◽  
Chemical Society ◽  
Geological Evidence ◽  
Water On Mars ◽  
Western Regional ◽  
Living Organisms ◽  
Aqueous Conditions

AbstractRecent findings on the presence of water on Mars (Baker, V.R. (2006). Geomorphological evidence for water on Mars. Elements2(3), 139–143; DeJong, E. (2006). Geological evidence of the presence of water on Mars. Abstracts from the 40th Western Regional Meeting of the American Chemical Society, Anaheim, CA, January, 2006, pp. 22–25. American Chemical Society, Washington, DC; McSween, H.Y. Jr. (2006). Water on Mars. Elements2(3), 135–137; Mitrofanov, I.G. (2005). Water explorations on Mars. Priroda9, 34–43) strongly suggest that there existed a period of chemical evolution eventually leading to life processes on primitive Mars (Kanavarioti, A. & Maneinelli, R.L. (1990). Could organic matter have been preserved on Mars for 3.5 billion years. Icarus84, 196–202). Owing to the adverse conditions, it is quite likely that the process of chemical evolution would have been suppressed and any living organisms that formed would have become extinct over time on Mars. The presence of water as a necessity for the survival of living organisms and the presence of grey haematite, originated under aqueous conditions, have led us to investigate the possible role of haematite in the chemical evolution on Mars. Our observations suggest that iron oxide hydroxide (FeOOH), a precursor of haematite, has a much higher binding affinity towards ribose nucleotides (the building blocks of RNA) than the haematite itself. This would mean that during the process of haematite formation, especially through the probable process of Fe3+ hydrolysis by aqueous ammonia, the precursors of haematite might have played a significant role in the processes leading to chemical evolution and the possible origin of life on Mars.

Preparation of Core-Shell Particles Consisted of Polysiloxane and Styrene-Butyl Methacrylate by High Internal Phase Emulsion

2014 ◽  
Vol 1033-1034 ◽  
pp. 996-1001
Author(s):  
Shao Jin Jia ◽  
Zhen Qi Zhang ◽  
Zhen Gang Ding ◽  
Xiao Tian Hou ◽  
Ping Kai Jiang
Keyword(s):  
Weight Ratio ◽  
Continuous Phase ◽  
Butyl Methacrylate ◽  
Core Shell ◽  
Water Contact ◽  
High Internal Phase Emulsion ◽  
Transmission Electron ◽  
Internal Phase ◽  
Shell Particles ◽  
Shell Composite

A core-shell composite polymer was produced by the method of high internal phase emulsion polymerization. The continuous phase of emulsion contained styrene(St), butyl methacrylate(BMA), octamethylcylotetrasiloxane(D4), and azobisisobutyronitrile (AIBN) which worked as an initiator. The block copolymers with St, BMA, D4 units are particularly promising for surface modification and hydrophobicity. The core-shell structure is proved by the use of Transmission electron microscopy (TEM). In addition, the water contact angle increased with the increasing weight ratio of D4. The results show that the concentrated emulsion system has good stability and the water resistance of the polymer has been improved greatly.

CADMIUM REMOVAL USING VEGETABLE OIL BASED EMULSION LIQUID MEMBRANE (ELM): MEMBRANE BREAKAGE INVESTIGATION

2015 ◽  
Vol 75 (1) ◽  
Author(s):  
A. L. Ahmad ◽  
M. M. H. Shah Buddin ◽  
B. S. Ooi ◽  
Adhi Kusumastuti
Keyword(s):  
Vegetable Oil ◽  
Liquid Membrane ◽  
Corn Oil ◽  
Volume Ratio ◽  
Aliquat 336 ◽  
Emulsion Liquid Membrane ◽  
Cadmium Removal ◽  
Internal Phase ◽  
External Phase ◽  
Span 80

The aim of this research is to quantify the occurrence of membrane breakage in vegetable oil based Emulsion Liquid Membrane (ELM). Basically, ELM consists of three main phases; internal, external and membrane. In this work, the membrane phase was prepared by dissolving Span 80 as surfactant and Aliquat 336 as carrier in commercial grade corn oil. As a way to promote sustainable development, vegetable oil which is environmentally benign diluent was incorporated in the formulation of ELM. The influence of several important parameters towards membrane breakage were studied. They are carrier and surfactant concentration, W/O volume ratio, emulsification time, internal phase concentration as well as stirring speed. Based on the data obtained, emulsion prepared using 4 wt% Aliquat 336 and 3 wt% Span 80 resulted in the most stable emulsion with only 0.05% membrane breakage. The emulsion was produced using W/O volume ratio of 1/3 and it was homogenized with the assistance of ultrasound for 15 min. Moreover, emulsion produced able to provide a fair balance between emulsion stability and Cd(II) permeability as it able to remove 98.20% Cd(II) ions from the external phase. 

scholarly journals Kinetics of the alkaline hydrolysis of crystal violet in micelles, reverse micelles and microemulsions of cetyltrimethylammonium bromide

1970 ◽  
Vol 24 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Ferdousi Begum ◽  
Md Yousuf A Molla ◽  
M Muhibur Rahman ◽  
Md Abu Bin Hasan Susan
Keyword(s):  
Crystal Violet ◽  
Alkaline Hydrolysis ◽  
Reverse Micelles ◽  
Cetyltrimethylammonium Bromide ◽  
Specific Conductivity ◽  
Water System ◽  
Chemical Society ◽  
Order Rate Constant ◽  
Kinetics Of ◽  
Hydrolysis Of

Kinetics of the alkaline hydrolysis of crystal violet (CV) in micelles, reverse micelles and microemulsions of a cationic surfactant, cetyltrimethylammonium bromide (CTAB) was studied at 25 ± 0.1 oC using spectrophotometric method. The rate of alkaline hydrolysis of CV was catalyzed by micellar solutions of CTAB. The pseudo first order rate constant (k') has been found to decrease upon incorporation of 1-butanol to cationic CTAB micelles, which displaces the substrate from the micellar into the aqueous phase. In CTAB/cyclohexane/1-butanol/water system, as the content of 1-butanol increases, specific conductivity and density of the microemulsions and reverse micelles decrease. The change in physical properties also causes change in reaction environment. A change from a micelle-rich (o/w) to a reverse micelle-rich (w/o) condition is apparent for microemulsions and consequently the k' vs. % wt. of 1-butanol profiles show an initial decrease in the k' followed by a gradual increase and finally, to a sharp increase with increasing 1-butanol content. Microemulsions and reverse micelles thus offer the potential to control rate of a reaction by formation of micelles in water phase and reverse micelles in oil phase. DOI: http://dx.doi.org/10.3329/jbcs.v24i2.9706 Journal of Bangladesh Chemical Society, Vol. 24(2), 173-184, 2011

scholarly journals DEVELOPMENT OF MICROEMULSION AND WATER/OIL/WATER MULTIPLE EMULSION CONTAINING BETA-ARBUTIN, LACTIC ACID, AND SODIUM ASCORBYL PHOSPHATE

2020 ◽  
pp. 212-220
Author(s):  
SILVIA SURINI ◽  
NUR MPN NEGORO
Keyword(s):  
Lactic Acid ◽  
Droplet Size ◽  
Physical Stability ◽  
Continuous Phase ◽  
Stability Studies ◽  
Flow Properties ◽  
Multiple Emulsion ◽  
Multiple Emulsions ◽  
Whitening Agent ◽  
Oil Water

Objective: In addition to lactic acid and sodium ascorbyl phosphate, which have whitening effects, beta-arbutin is a safe whitening agent for skin.Combining these three substances should reduce the concentration of each one in a formula and achieve an optimal whitening effect. In this study,microemulsions and water/oil/water (W/O/W) multiple emulsions were applied to produce a formula containing these whitening agents.Methods: All the active ingredients were formulated into microemulsions and W/O/W multiple emulsions with different concentrations of Tween 80and Span 80 as emulsifiers to obtain a stable formula. Twelve-week physical stability studies were performed for every formula at low (4±2°C), room(28±2°C), and high (40±2°C) temperatures.Results: The produced microemulsions were transparent with a mean droplet size of 15.50 nm. In addition, the W/O/W multiple emulsions containeddroplets within droplets, which were dispersed in a continuous phase with an inner droplet size of 0.15 μm and an outer droplet size of 0.37 μm. TheW/O/W multiple emulsions showed pseudoplastic thixotropic flow properties. Furthermore, the microemulsions were stable at low (4±2°C) androom (28±2°C) temperatures, while the W/O/W multiple emulsions were stable at room (28±2°C) and high (40±2°C) temperatures.Conclusion: It was concluded that the combination of beta-arbutin, lactic acid, and sodium ascorbyl phosphate was suitable for formulating intomicroemulsions as well as W/O/W multiple emulsions as whitening cosmetic products.

SIMULATION OF CO-PLANAR WAVEGUIDE LIQUID CRYSTAL BASED PHASE SHIFTER

2015 ◽  
Vol 77 (10) ◽  
Author(s):  
Nasser A ALQuaiti ◽  
Noor Asniza Murad
Keyword(s):  
Liquid Crystal ◽  
Phase Shift ◽  
Phase Shifter ◽  
Low Cost ◽  
Continuous Phase ◽  
Phase Shifting ◽  
Telecommunication System ◽  
Liquid Crystal Material ◽  
Compact Size ◽  
5Cb Liquid Crystal

This paper discussed the design and performances of a liquid crystal phase shifter that can be used in tuning devices. Tuning devices growth with the demand in the emerging in telecommunication system. Tuning devices with smooth continuous phase shifting at low cost and compact size would be an advantage. This paper proposed a phase shifter using 5CB liquid crystal material. The advantages of using the material is the smoothness and continuity of the transitions in the phase shift. It is done by having a structure with cavity filled with the liquid crystal and applied with certain voltage that can be changed. The changes in voltage would change the applied electric field, and thus would change the permittivity of the material. The changes would affect the wave propagation and thus contribute to the phase shifting. The performance of the phase shifter was tested by means of simulation using CST Suite 2014 software. The results show that the higher the frequency, the higher the phase shift would occur. The highest FoM achieved is 68 (deg/dB) at 8 GHz. A phase shifter with smooth and continuous phase shift can be used as the feeding network in an array scanning antennas systems.

scholarly journals The Influence of Co-Surfactants on Lamellar Liquid Crystal Structures Formed in Creams

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 864
Author(s):  
Delaram Ahmadi ◽  
Najet Mahmoudi ◽  
Richard K. Heenan ◽  
David J. Barlow ◽  
M. Jayne Lawrence
Keyword(s):  
Liquid Crystal ◽  
Crystal Structures ◽  
Small Angle ◽  
Liquid Paraffin ◽  
Sodium Dodecyl ◽  
Ternary Systems ◽  
Continuous Phase ◽  
Lamellar Liquid Crystal ◽  
X Ray Scattering ◽  
Oil In Water

It is well-established that oil-in-water creams can be stabilised through the formation of lamellar liquid crystal structures in the continuous phase, achieved by adding (emulsifier) mixtures comprising surfactant(s) combined (of necessity) with one or more co-surfactants. There is little molecular-level understanding, however, of how the microstructure of a cream is modulated by changes in co-surfactant and of the ramifications of such changes on cream properties. We investigate here the molecular architectures of oil-free, ternary formulations of water and emulsifiers comprising sodium dodecyl sulfate and one or both of the co-surfactants hexadecanol and octadecanol, using microscopy, small-angle and wide-angle X-ray scattering and small-angle neutron scattering. We then deploy these techniques to determine how the structures of the systems change when liquid paraffin oil is added to convert them to creams, and establish how the structure, rheology, and stability of the creams is modified by changing the co-surfactant. The ternary systems and their corresponding creams are shown to contain co-surfactant lamellae that are subtly different and exhibit different thermotropic behaviours. The lamellae within the creams and the layers surrounding their oil droplets are shown to vary with co-surfactant chain length. Those containing a single fatty alcohol co-surfactant are found to contain crystallites, and by comparison with the cream containing both alcohols suffer adverse changes in their rheology and stability.

scholarly journals Water Droplets Translocation and Fission in a 3D Bi-Planar Multifurcated T-Junction Microchannels

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 510
Author(s):  
Inn-Leon Lu ◽  
Voon-Loong Wong ◽  
Jit-Kai Chin ◽  
Kuzilati Kushaari
Keyword(s):  
Droplet Size ◽  
Flow Behavior ◽  
Phase 1 ◽  
Maximum Velocity ◽  
Droplet Size Distribution ◽  
Continuous Phase ◽  
Fission Process ◽  
Model Studies ◽  
Daughter Droplets ◽  
Droplet Fission

Droplet fission has gained notable interest in drug delivery applications due to its ability to perform parallel operations in single device. Hitherto, droplet flow behavior in a 3D constriction was scarcely investigated. This study aims to investigate droplets fission inside a 3D bi-planar multifurcated microfluidic device. The flow behavior and droplet size distribution were studied in trifurcated microchannels using distilled water as dispersed phase (1 mPa·s) and olive oil (68 mPa·s) as continuous phase. Various sizes of subordinate daughter droplets were manipulated passively through the modulation of flowrate ratio (Q) (0.15 < Q < 3.33). Overall, we found droplet size coefficient of variations (CV%) ranging from 0.72% to 69%. Highly monodispersed droplets were formed at the upstream T-junction (CV% < 2%) while the droplet fission process was unstable at higher flowrate ratio (Q > 0.4) as they travel downstream (1.5% < CV% < 69%) to splitting junctions. Complex responses to the non-monotonic behavior of mean droplet size was found at the downstream boundaries, which arose from the deformations under nonuniform flow condition. CFD was used as a tool to study the preliminary maximum velocity (Umax) profile for the symmetrical (0.01334 m/s < Umax < 0.0153 m/s) and asymmetrical branched channels (0.0223 m/s< Umax < 0.00438 m/s), thus complementing the experimental model studies.

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