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This and the following five slides are from:
A. Fery, F. Dubreuil and H. Möhwald (Max-Planck Institute of Colloids and Interfaces, D 14424 Potsdam, Germany),
"Mechanics of artificial microcapsules", New Journal of Physics, Vol. 6, 2004, 18,
doi: 10.1088/1367-2630/6/1/018
ABSTRACT: In recent years, an increasing number of microcapsule systems have been realized and have found applications in various fields of research and technology. Amongst others, polyelectrolyte multilayer capsules (PMCs) offer a great variety of materials and superior control over the wall thicknesses. We present here a review on the different techniques that are available for characterizing the mechanical properties of PMCs. We compare results that were obtained using these techniques on the same system, namely PMCs made from polyallylamine and polystyrenesulfonate multilayers and discuss perspectives of the field.
This figure shows schematically production of hollow polyelectrolyte multilayer capsules (PMCs) by coating of colloidal particles (a, b) and subsequent dissolution of the colloidal inner layer under conditions that do not destabilize the multilayers (c, d).
It is necessary to determine the mechanical properties of a PMC. One of the ways of doing this is to observe the dependence of external osmotic buckling pressure on the normalized wall thickness t/R of the PMC and then to derive the modulus of the PMC from the classical buckling load formula for a perfect externally pressurized spherical shell, as demonstrated in the next two slides.
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