Imperial College London
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DrValeriaGarbin

Faculty of Engineering, Department of Chemical Engineering

Visiting Professor
 
 
 
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Contact

 

v.garbin

 
 
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Assistant

 

Ms Sevgi Thompson +44 (0)20 7594 1478

 
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Location

 

ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Poulichet:2016:10.1039/C6SM01603K,
author = {Poulichet, V and Huerre, A and Garbin, V},
doi = {10.1039/C6SM01603K},
journal = {Soft Matter},
pages = {125--133},
title = {Shape oscillations of particle-coated bubbles and directional particle expulsion},
url = {http://dx.doi.org/10.1039/C6SM01603K},
volume = {13},
year = {2016}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Bubbles stabilised by colloidal particles can find applications in advanced materials, catalysis anddrug delivery. For applications in controlled release, it is desirable to remove the particles fromthe interface in a programmable fashion. We have previously shown that ultrasound waves excitevolumetric oscillations of particle-coated bubbles, resulting in precisely timed particle expulsiondue to interface compression on a ultrafast timescale [Poulichet et al., Proc. Natl. Acad. Sci.USA, 2015, 112, 5932]. We also observed shape oscillations, which were found to drive directionalparticle expulsion from the antinodes of the non-spherical deformation. In this paper weinvestigate the mechanisms leading to directional particle expulsion during shape oscillations ofparticle-coated bubbles driven by ultrasound at 40 kHz. We perform high-speed visualisation ofthe interface shape and of the particle distribution during ultrafast deformation at a rate of upto 105 s−1. The mode of shape oscillations is found to not depend on the bubble size, in contrastwith what has been reported for uncoated bubbles. A decomposition of the non-sphericalshape in spatial Fourier modes reveals that the interplay of different modes determines the locationsof particle expulsion. The n-fold symmetry of the dominant mode does not always leadto desorption from all 2n antinodes, but only those where there is favourable alignment with thesub-dominant modes. Desorption from the antinodes of the shape oscillations is due to different,concurrent mechanisms. The radial acceleration of the interface at the antinodes can be upto 105 − 106 ms−2, hence there is a contribution from the inertia of the particles localised at theantinodes. In addition, we found that particles migrate to the antinodes of the shape oscillation,thereby enhancing the contribution from the surface pressure in the monolayer.
AU  - Poulichet,V
AU  - Huerre,A
AU  - Garbin,V
DO  - 10.1039/C6SM01603K
EP  - 133
PY  - 2016///
SN  - 1744-6848
SP  - 125
TI  - Shape oscillations of particle-coated bubbles and directional particle expulsion
T2  - Soft Matter
UR  - http://dx.doi.org/10.1039/C6SM01603K
UR  - http://hdl.handle.net/10044/1/39775
VL  - 13
ER  -
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