Aqueous foams stabilized solely by particles

Stocco, Antonio; Rio, Emmanuelle; Binks, Bernard P.; Langévin, D.

doi:10.1039/c0sm01290d

Cited by 216 publications

(165 citation statements)

References 45 publications

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“…38,39 The intensity of this barrier can be surprisingly higher than the hydrodynamic forces pushing the particle towards the droplet. 40,41 As a result of that, even in the presence of weak forces, external work must be often applied via high shear or sonication in order to observe adsorption of particles at a reasonable rate, which would confirm our results. 41,42 Furthermore, curvature effects may play a role.…”

Section: On the Adsorption Of The Pickering Stabilizer Onto Monomer Dsupporting

confidence: 79%

A mechanistic investigation of Pickering emulsion polymerization

Lotierzo

Bon

2017

Polym. Chem.

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A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. Pickering emulsion polymerization offers a versatile way of synthetising hybrid core-shell latexes where a polymer core is surrounded by an armour of inorganic nanoparticles. A mechanistic understanding of the polymerization process is limited which restricts the use of the technique in the fabrication of more complex, multilayered colloids. In this paper clarity is provided through an in-depth investigation into the Pickering emulsion polymerization of methyl methacrylate (MMA) in the presence of nano-sized colloidal silica (Ludox TM-40). Mechanistic insights are discussed by studying both the adsorption of the stabiliser to the surface of the latex particles and polymerization kinetics. The adhesion of the Pickering nanoparticles was found not to be spontaneous, as confirmed by cryo-TEM analysis of MMA droplets in water and monomer-swollen PMMA latexes. This supports the theory that the inorganic particles are driven towards the interface as a result of a heterocoagulation event in the water phase with a growing oligoradical. The emulsion polymerizations were monitored by reaction calorimetry in order to establish accurate values for monomer conversion and the overall rate of polymerizations (Rp). Rp increased for higher initial silica concentrations and the polymerizations were found to follow pseudo-bulk kinetics.

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Section: On the Adsorption Of The Pickering Stabilizer Onto Monomer Dsupporting

confidence: 79%

A mechanistic investigation of Pickering emulsion polymerization

Lotierzo

Bon

2017

Polym. Chem.

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“…Alternatively, the stabilized particles are too hydrophilic, leading to preferential partitioning into the aqueous phase. This energy barrier can be overcome by applying high energy forces such as turbulent mixing and using a combination of particles and proteins giving an appropriate contact angle at the air-water surface (close to 90°) [31]. Once particles are adsorbed at the interface of an air bubble, it is almost impossible to force them out of the interface, indicating a network formation at the interface.…”

Section: Np-stabilized Mbsmentioning

confidence: 99%

Nanoparticle‐stabilized microbubbles for multimodal imaging and drug delivery

Mørch

Hansen

Berg

et al. 2015

Contrast Media & Molecular

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Microbubbles (MBs) are routinely used as contrast agents for ultrasound imaging. The use of ultrasound in combination with MBs has also attracted attention as a method to enhance drug delivery.We have developed a technology platform incorporating multiple functionalities, including imaging and therapy in a single system consisting of MBs stabilized by polyethylene glycol (PEG) coated polymeric nanoparticles (NPs). The NPs, containing lipophilic drugs and/or contrast agents, are composed of the widely used poly(butyl cyanoacrylate) (PBCA) polymer and prepared in a single step. MBs stabilized by these NPs are subsequently prepared by self-assembly of NPs at the MB air/liquid interface. Here we show that these MBs can act as contrast agents for conventional ultrasound imaging. Successful encapsulation of iron oxide NPs inside the PBCA NPs is demonstrated, potentially enabling the NPs/MBs to be used as magnetic resonance imaging (MRI) and/or molecular ultrasound imaging contrast agents. By precise tuning of the applied ultrasound pulse, the MBs burst and the NPs constituting the shell are released. This could result in increased local deposit of NPs into target tissue providing improved therapy and imaging contrast compared to freely distributed NPs.

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“…Since demonstrating the feasibility of the method 13,19 , there has been much interest in the study of particle stabilised bubbles, 3,14,[20][21][22][23][24][25] though preparation of Pickering bubbles still remains a more difficult proposition compared to Pickering emulsions. 26 In achieving the desired bubble stability a number of points have to be considered. In all cases it is necessary to achieve the correct balance of surface activity versus the tendency for bulk aggregation.…”

Section: Introductionmentioning

confidence: 99%

Effect of particle adsorption rates on the disproportionation process in pickering stabilised bubbles

Ettelaie

Murray

2014

The Journal of Chemical Physics

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The degree of shrinkage of particle stabilised bubbles of various sizes, in a polydisperse bubble dispersion, has been investigated in the light of the finite adsorption times for the particles and the disproportionation kinetics of the bubbles. For the case where the system contains an abundance of particles we find a threshold radius, above which bubbles are stabilised without any significant reduction in their size. Bubbles with an initial radius below this threshold on the other hand, undergo a large degree of shrinkage prior to stabilisation.As the ratio of the available particles to the bubbles is reduced, it is shown that the final bubble size, for the larger bubbles in the distribution, becomes increasingly governed by the number of particles, rather than their adsorption time per se. For systems with "adsorption controlled" shrinkage ratio, the final bubble distribution is found to be wider than the initial one, while for a "particle number controlled" case it is actually narrower. Starting from an unimodal bubble size distribution, we predict that at intermediate times, prior to the full stabilisation of all bubbles, the distribution breaks up into a bimodal one. However, the effect is transient and an unimodal final bubble size distribution is recovered once again, when all the bubbles are stabilised by the particles.-3-1

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Aqueous foams stabilized solely by particles

Cited by 216 publications

References 45 publications

A mechanistic investigation of Pickering emulsion polymerization

A mechanistic investigation of Pickering emulsion polymerization

Nanoparticle‐stabilized microbubbles for multimodal imaging and drug delivery

Effect of particle adsorption rates on the disproportionation process in pickering stabilised bubbles

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