Direct Measurement of Contact Angles of Silica Particles in Relation to Double Inversion of Pickering Emulsions

Langmuir ◽  
2013 ◽  
Vol 29 (16) ◽  
pp. 4923-4927 ◽  
Author(s):  
Bernard Paul Binks ◽  
Lucio Isa ◽  
Andrew Terhemen Tyowua
Keyword(s):  
Direct Measurement ◽  
Contact Angles ◽  
Silica Particles ◽  
Pickering Emulsions

scholarly journals Enzyme-Loaded Mesoporous Silica Particles with Tuning Wettability as a Pickering Catalyst for Enhancing Biocatalysis

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 78 ◽  
Author(s):  
Tao Meng ◽  
Ruixue Bai ◽  
Weihao Wang ◽  
Xin Yang ◽  
Ting Guo ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Enzymatic Reaction ◽  
Interfacial Area ◽  
Mass Transfer Process ◽  
Pickering Emulsion ◽  
Contact Angles ◽  
Silica Particles ◽  
Emulsion System ◽  
Pickering Emulsions ◽  
Two Phase

Pickering emulsion systems have created new opportunities for two-phase biocatalysis, however their catalytic performance is often hindered by biphasic mass transfer process relying on the interfacial area. In this study, lipase-immobilized mesoporous silica particles (LMSPs) are employed as both Pickering stabilizers and biocatalysts. A series of alkyl silanes with the different carbon length are used to modify LMSPs to obtain suitable wettability and enlarge the interfacial area of Pickering emulsion. The results show the water/paraffin oil Pickering emulsions stabilized by 8 carbon atoms silane grafted LMSPs (LMSPs_C8) with a three-phase contact angles of 95° get the relatively large interfacial area. Moreover, the conversion of enzymatic reaction catalyzed by LMSPs_C8 Pickering emulsion system is 3.4 times higher than that unmodified LMSPs with the reaction time of 10 min. Additionally, the effective recycling of LMSPs is achieved by simple low-speed centrifugation. As evidenced by a 6-cycles reaction of remaining 75% of relative enzymatic activity, the protection of 350–450 nm mesoporous silica particles can alleviate the inactivation of enzyme from the shear stress and make a benefit to form stabile Pickering emulsion. Therefore, the biphasic reactions in the Pickering emulsion system can be effectively enhanced through changing interfacial area only by the means of adjusting the wettability of biocatalysts.

Pickering Emulsions of Hydrophilic Silica Particles and Symmetrical Organic Electrolytes

Langmuir ◽  
2020 ◽  
Vol 36 (17) ◽  
pp. 4619-4629
Author(s):  
Raojun Zheng ◽  
Bernard P. Binks ◽  
Zhenggang Cui
Keyword(s):  
Silica Particles ◽  
Pickering Emulsions ◽  
Organic Electrolytes

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.

Influence of different surfactants on Pickering emulsions stabilized by submicronic silica particles

2018 ◽  
Vol 520 ◽  
pp. 127-133 ◽  
Author(s):  
Khaoula Lebdioua ◽  
Anne Aimable ◽  
Manuella Cerbelaud ◽  
Arnaud Videcoq ◽  
Claire Peyratout
Keyword(s):  
Silica Particles ◽  
Pickering Emulsions

scholarly journals Numerical analysis of Pickering emulsion stability: insights from ABMD simulations

2016 ◽  
Vol 191 ◽  
pp. 287-304 ◽  
Author(s):  
François Sicard ◽  
Alberto Striolo
Keyword(s):  
Early Stage ◽  
Dissipative Particle Dynamics ◽  
Contact Angles ◽  
Hydrodynamic Resistance ◽  
Interfacial Region ◽  
Dense Layer ◽  
Pickering Emulsions ◽  
Mesoscopic Level ◽  
Nanoparticle Mobility ◽  
Dynamics Simulations

The issue of the stability of Pickering emulsions is tackled at a mesoscopic level using dissipative particle dynamics simulations within the Adiabatic Biased Molecular Dynamics framework. We consider the early stage of the coalescence process between two spherical water droplets in a decane solvent. The droplets are stabilized by Janus nanoparticles of different shapes (spherical and ellipsoidal) with different three-phase contact angles. Given a sufficiently dense layer of particles on the droplets, we show that the stabilization mechanism strongly depends on the collision speed. This is consistent with a coalescence mechanism governed by the rheology of the interfacial region. When the system is forced to coalesce sufficiently slowly, we investigate at a mesoscopic level how the ability of the nanoparticles to stabilize Pickering emulsions is discriminated by nanoparticle mobility and the associated caging effect. These properties are both related to the interparticle interaction and the hydrodynamic resistance in the liquid film between the approaching interfaces.

scholarly journals Synthesis of Silica Particles from Sugarcane Bagasse Ash for Its Application in Hydrophobic Coatings

2020 ◽  
Vol 2 (1) ◽  
pp. 4
Author(s):  
Jesús A. Pérez-Casas ◽  
Antonio A. Zaldívar-Cadena ◽  
Anabel Álvarez-Mendez ◽  
Juan Jacobo Ruiz-Valdés ◽  
Salomé M. de la Parra-Arciniega ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Sugarcane Bagasse ◽  
Building Materials ◽  
Contact Angles ◽  
Silica Particles ◽  
Raw Material ◽  
Molar Ratio ◽  
Future Application ◽  
Water Contact ◽  
Sugarcane Bagasse Ash

: Wastes such as sugarcane bagasse ash (SCBA) can be used as raw material in ceramics by the elaboration of bricks and tiles and the glass industry, due the high amount of silica in its composition (>70%). Another application for SCBA is the synthesis of metallic silicates. In this work, we study the synthesis of sodium silicate with SCBA as the main raw material and the future application of sodium silicate for the preparation of silica particles in order to create hydrophobic surfaces for ceramic materials to prevent their erosion. The sodium silicate synthesis was carried out by the thermochemical method with batches of ash and sodium carbonate in a 1:1 sodium oxide–silicon oxide molar ratio. The thermal treatment was in an electric furnace at 800 °C for 8 h. Then, for the synthesis of the silica particles, the sodium silicate was dissolved in water, and then we added methanol in a 3:2 water methanol volume ratio. The solution was left to age for an hour to create the Si-OH bond. Finally, tetraethylorthosilicate (TEOS) was added and the solution was stirred for 2 h to create a hydrophobic and hydrolytically resistant siloxane by the displacement of H in the Si-OH bond. The application of the solution was by the spray-coating method over substrates of concrete and red clay with the application of 10, 15, and 20 layers. The hydrophobicity was evaluated with the water contact angle test, with the results of contact angles above the 110°, thus demonstrating the capacity of a waste for the generation of coatings to prolong the useful life of building materials.

Hydrophilic and hydrophobic modifications of colloidal silica particles for Pickering emulsions

2017 ◽  
Vol 487 ◽  
pp. 250-257 ◽  
Author(s):  
Sanna Björkegren ◽  
Lars Nordstierna ◽  
Anders Törncrona ◽  
Anders Palmqvist
Keyword(s):  
Colloidal Silica ◽  
Silica Particles ◽  
Pickering Emulsions
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