Silica nanoparticles catalyse the formation of silica nanocapsules in a surfactant-free emulsion system

Zhao, Yongliang; Chen, Zhi; Zhu, Xiaomin; Möller, Martin

doi:10.1039/c5ta06947e

Cited by 25 publications

(34 citation statements)

References 50 publications

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“…So far all the experiments are performed using deionized water of pH 7 for both inner and outer aqueous phases. As shown in our previous studies, the pH value of the aqueous phase can significantly influence the conversion of PEOS, thus affecting the emulsion stability and morphology of the final capsular structure 24 – 26 , 28 . The pH of both inner and outer aqueous phases is systematically varied from acidic to basic (entries 6–16 in Table 1 ).…”

Section: Resultsmentioning

confidence: 63%

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Hybrid nanostructured particles via surfactant-free double miniemulsion polymerization

et al. 2018

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Double emulsions are complex fluid systems, in which droplets of a dispersed liquid phase contain even smaller dispersed liquid droplets. Particularly, water-in-oil-in-water double emulsions provide significant advantages over simple oil-in-water emulsions for microencapsulation, such as carrier of both aqueous and oily payloads and sustained release profile. However, double emulsions are thermodynamically unstable systems consisting typically of relatively large droplets. Here we show that nanoscale water-in-oil-in-water double emulsions can be prepared by adding a silica precursor polymer, hyperbranched polyethoxysiloxane, to the oil phase without any additional surfactants. The resulting double miniemulsions are transformed to robust water@SiO2@polymer@SiO2 nanocapsules via conversion of the precursor to silica and polymerization of the oil phase. Other intriguing nanostructures like nanorattles and Janus-like nanomushrooms can also be obtained by changing preparation conditions. This simple surfactant-free double miniemulsion polymerization technique opens a promising avenue for mass production of various complex hybrid nanostructures that are amenable to numerous applications.

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Section: Resultsmentioning

confidence: 63%

“…Recently, we reported the formation of O/W miniemulsions by emulsifying a solution of a silica precursor polymer, hyperbranched polyethoxysiloxane (PEOS) 23 , in a hydrophobic liquid in water 24 , 25 . PEOS is a water-insoluble liquid, which becomes amphiphilic upon hydrolysis at the oil/water interface.…”

Section: Introductionmentioning

confidence: 99%

Hybrid nanostructured particles via surfactant-free double miniemulsion polymerization

et al. 2018

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“…24 PEOS has many advantageous properties compared to low-molecular weight SiO 2 precursors (e.g., TEOS), like high SiO 2 content, high hydrophobicity, non-volatility, high functionality, processability to films and fibers as well as interfacial activity in an oil-water system. 41,42 Favorably, it is miscible in variable ratios in melt or solution with the TM and enables precise adjustment of ratios of organic to inorganic phase. In the present work, TM is polymerized in the presence of PEOS (Scheme 3) under formation of a phenolic resin-SiO 2 hybrid material.…”

Section: Introductionmentioning

confidence: 99%

Textile functionalization by combination of twin polymerization and polyalkoxysiloxane‐based sol–gel chemistry

Kaßner

Zhu

Schaefer

et al. 2022

J of Applied Polymer Sci

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The surface modification of textile fibers by coating with nanostructured organic–inorganic hybrid materials is presented. The hydrophobic, solvent resistant and mechanically robust coatings were produced by combining the twin monomer 2,2′‐spirobi[benzo‐4H‐1,3,2‐dioxasiline] (TM) and polyalkoxysiloxanes (silica precursor polymers) in a catalyzed polymerization process. For the application in textile finishing, both aqueous emulsions and ethanolic solutions of mixtures were developed. The precisely adjusted ratio of TM and polyalkoxysiloxanes enabled controlling of the organic and inorganic portions in the hybrid layer. The polymerization process can be advantageously combined with the ring‐opening polymerization of hexamethylcyclotrisiloxane (HMCTS). The resulting ethanolic twin prepolymer solutions and the polyethoxysiloxane emulsions were easy to handle and thus represent a novel and attractive binder for PET surfaces. The coated fabrics were analyzed by means of scanning electron microscopy and X‐ray photoelectron spectroscopy showing hybrid material formation as a homogeneous, sealed surface layer. Improved hydrophobicity as well as resistance to mechanical stress was proven by water droplet‐ and Martindale tests.

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“…The former could be separated easily under gravity. The latter could hardly dispart from water due to the dynamic stabilization of emulsion system . So the strong external chemical or physical actions on oil/water interface are needed for demulsification, such as air flotation, absorption, centrifugalization, coagulation, flocculation, etc .…”

Section: Introductionmentioning

confidence: 99%

Cellulose Sponge with Superhydrophilicity and High Oleophobicity Both in Air and under Water for Efficient Oil–Water Emulsion Separation

Chen

Zhang

Cheng

et al. 2017

Macro Materials & Eng

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Oil–water emulsions stabilized by surfactants are fine dispersions of oil in water or of water in oil and difficult to separate which will lead to serious water pollution. A more recent development is the ability to fabricate oleophobic–hydrophilic surfaces in air, which are not easy to construct due to the difference surface tension between water and oil. Herein, a cellulose sponge with multipore structure is fabricated to increase the removal efficiency. Amphiphilic molecular brushes of polyethylene glycol with short perfluorinated end caps (F‐PEG) are grafted on cellulose sponges to solve the contradictory relation of hydrophilicity and oleophobicity and improve oil/water selective wettability and fouling resistance. Besides, stable superhydrophilicity and superoleophobicity under water, corrosive liquids, and high oleophobicity in air conditions are exhibited in the F‐PEG grafted porous cellulose sponges with textured surfaces (F‐g‐CS). And the separation efficiency and rate of F‐g‐CS with surface of nanopores are 99.92% and 180 L m−2 h−1, while that of micropores are 99.83% and 297 L m−2 h−1 only under gravity. It is demonstrated that the grafting F‐PEG molecules imparted F‐g‐CS of micropores surface with high flux and separation efficiency simultaneously. Furthermore, antifouling property and collection of water in oil–water mixture without fouling are possessed in F‐g‐CS.

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Silica nanoparticles catalyse the formation of silica nanocapsules in a surfactant-free emulsion system

Abstract: Interplay between methylated silica nanoparticles and polyethoxysiloxane at oil/water interface leads to a variety of silica capsule structures.

Cited by 25 publications

References 50 publications

Hybrid nanostructured particles via surfactant-free double miniemulsion polymerization

Hybrid nanostructured particles via surfactant-free double miniemulsion polymerization

Textile functionalization by combination of twin polymerization and polyalkoxysiloxane‐based sol–gel chemistry

Cellulose Sponge with Superhydrophilicity and High Oleophobicity Both in Air and under Water for Efficient Oil–Water Emulsion Separation

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