Stability of oil-in-water emulsions stabilised by silica particles

1999 ◽  
Vol 1 (12) ◽  
pp. 3007-3016 ◽  
Author(s):  
B P. Binks ◽  
S O. Lumsdon
Keyword(s):  
Silica Particles ◽  
Oil In Water

Effect of electrolyte in silicone oil-in-water emulsions stabilised by fumed silica particles

2007 ◽  
Vol 9 (48) ◽  
pp. 6398 ◽  
Author(s):  
Tommy S. Horozov ◽  
Bernard P. Binks ◽  
Torsten Gottschalk-Gaudig
Keyword(s):  
Fumed Silica ◽  
Silicone Oil ◽  
Silica Particles ◽  
Oil In Water

Preparation of a synergistically stabilized oil-in-water paraffin Pickering emulsion for potential application in wood treatment

Holzforschung ◽  
2018 ◽  
Vol 72 (6) ◽  
pp. 489-497 ◽  
Author(s):  
Jun Jiang ◽  
Jinzhen Cao ◽  
Wang Wang ◽  
Haiying Shen
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Size Distribution ◽  
Droplet Size ◽  
Surface Hardness ◽  
Pickering Emulsion ◽  
Silica Particles ◽  
Morphological Properties ◽  
Pickering Emulsions ◽  
Oil In Water

AbstractPickering emulsions (emulsions stabilized by solid-state additives) are attractive as they have strong similarities with traditional surfactant-based emulsions. In this study, an oil-in-water (O/W) paraffin Pickering emulsion system with satisfying stability and small droplet size distribution was developed by hydrophilic silica particles and traditional surfactants as mixed emulsifiers. The droplet morphology and size distribution were observed by optical microscopy and a laser particle analyzer. The emulsion stability was improved and the droplet size was reduced after addition of a suitable amount of silica particles. The silica concentration of 1% showed the optimal effect among all the levels observed (0.1, 0.5, 1 and 2%). Wood was impregnated with the prepared emulsion, and the chemical and morphological properties of the product were investigated by Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) combined with energy-dispersed X-ray analysis (SEM-EDXA). Moreover, the hydrophobicity, thermal properties, surface hardness, axial compression strength (CS) and dynamic mechanical properties were tested. The silica was evenly distributed in the wood cell wall and thus there was a synergistic positive effect from the paraffin and silica in the cell wall leading to better hydrophobicity, improved surface hardness and mechanical properties including the thermal stability.

Preparation and Flow Behaviour of Oil-In-Water Emulsions Stabilised by Hydrophilic Silica Particles

2009 ◽  
Vol 32 (7) ◽  
pp. 1107-1112 ◽  
Author(s):  
B. Braisch ◽  
K. Köhler ◽  
H. P. Schuchmann ◽  
B. Wolf
Keyword(s):  
Silica Particles ◽  
Flow Behaviour ◽  
Oil In Water

scholarly journals HYDROPHOBIZATION OF SILICA PARTICLES WITH VARIOUS CATIONIC SURFACTANTS

2021 ◽  
Vol 64 (3) ◽  
pp. 41-45
Author(s):  
Alla V. Nushtaeva ◽  
Natalia G. Vilkova
Keyword(s):  
Contact Angle ◽  
Aqueous Phase ◽  
Volume Fraction ◽  
Saturated Hydrocarbon ◽  
Vertical Surface ◽  
Contact Angles ◽  
Silica Particles ◽  
Sessile Droplet ◽  
Phase Volume Fraction ◽  
Oil In Water

Silica particles with a radius of 3-7 nm (Ludox and Aerosil) and 270 nm (synthesized by the Stöber method), modified with cetyltrimethylammonium bromide (CTAB) and hexylamine, were used to stabilize emulsions. The hysteresis angles θ of the particle selective wetting were measured by the sessile droplet method on the vertical surface or by the pulling a ball method at using a glass substrate modified by contact coagulation of silica. The contact angle at the boundary between the aqueous phase and the saturated hydrocarbon (octane, decane) reached the values θrec = 53 ± 2 ° and θadv = 116 ± 4 ° (the aqueous phase receding and advancing angle, respectively) with an increase in the initial concentration of long-chain CTAB to (1.4–9.5)·10–2 mmol/g of silica. With a further increase in CTAB concentration, a second reoriented layer was formed, which lowered the contact angle. Accordingly, using CTAB, only oil-in-water emulsions were obtained with the oil phase volume fraction Øoil = 0.5. The amount of short-chain hexylamine required to start stabilizing the emulsions turned out to be 2-3 orders of magnitude higher than the amount of CTAB. At using hexylamine, it was possible to increase the contact angle up to the values θrec ≈ θadv = 163 ± 12 ° at a concentration of 7-21 mmol/g. This is due to the fact that hexylamine is not characterized by formation of micelle or reoriented layers. Apparently, the adsorption of hexylamine is possible not only on dissociated silanol groups Si–OH, but also on siloxane groups Si–O–Si≡, which makes it possible to make the silica surface superhydrophobic. The measured contact angles were correlated with the region of stable oil-in-water and water-in-oil emulsions.

scholarly journals Encapsulation of Lactobacillus casei (ATCC 393) by Pickering-Stabilized Antibubbles as a New Method to Protect Bacteria against Low pH

2020 ◽  
Vol 4 (3) ◽  
pp. 40
Author(s):  
Vida Mardani Ghahfarokhi ◽  
Paolo P. Pescarmona ◽  
Gert-Jan W. Euverink ◽  
Albert T. Poortinga
Keyword(s):  
Aqueous Phase ◽  
Lactobacillus Casei ◽  
Silica Particles ◽  
Low Ph ◽  
New Method ◽  
Liquid Droplets ◽  
Freeze Dried ◽  
Oil In Water

Pickering-stabilized antibubbles were used as a new method to encapsulate Lactobacillus casei. Antibubbles consist of one or more liquid droplets within a shell of gas. The antibubbles were prepared from a water-in-oil-in-water (W/O/W) emulsion stabilized by silica particles, which was then freeze-dried to remove the water and oil phases, before being subsequently reconstituted in water. Different oil phases and aqueous phase compositions were tested for their effect on the survival of the bacteria. The survival of L. casei after encapsulation using decane was 29.8 ± 2.1% in antibubbles containing 10% (w/v) maltodextrin plus 8% (w/v) sucrose, which is comparable to the survival when bacteria were freeze-dried without being encapsulated. Encapsulation within antibubbles led to a 10 to 30 times higher survival of L. casei at pH 2 in comparison with unencapsulated bacteria. This study shows that probiotics can be encapsulated within a shell of gas through the use of antibubbles and that this protects probiotics against a low pH.

Quantification of Silica Uptake by Alveolar Macrophages - An Emperical Scanning Electron Microprobe Method

1982 ◽  
Vol 40 ◽  
pp. 332-333
Author(s):  
V. V. Damiano ◽  
R. P. Daniele ◽  
H. T. Tucker ◽  
J. H. Dauber
Keyword(s):  
Quantitative Analysis ◽  
Alveolar Macrophages ◽  
Bulk Sample ◽  
Silica Particles ◽  
Empirical Method ◽  
Phagocytic Cells ◽  
Calibration Standards ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Scanning Electron

An important example of intracellular particles is encountered in silicosis where alveolar macrophages ingest inspired silica particles. The quantitation of the silica uptake by these cells may be a potentially useful method for monitoring silica exposure. Accurate quantitative analysis of ingested silica by phagocytic cells is difficult because the particles are frequently small, irregularly shaped and cannot be visualized within the cells. Semiquantitative methods which make use of particles of known size, shape and composition as calibration standards may be the most direct and simplest approach to undertake. The present paper describes an empirical method in which glass microspheres were used as a model to show how the ratio of the silicon Kα peak X-ray intensity from the microspheres to that of a bulk sample of the same composition correlated to the mass of the microsphere contained within the cell. Irregular shaped silica particles were also analyzed and a calibration curve was generated from these data.

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