Issue 5, 2013
From the journal:

Soft Matter

Charged microcapsules for controlled release of hydrophobic actives. Part I: encapsulation methodology and interfacial properties†

Markus Andersson Trojer,*a   Ye Li,a   Christoffer Abrahamsson,a   Azmi Mohamed,b   Julian Eastoe,b   Krister Holmberga  and  Magnus Nydénac  

* Corresponding authors

a Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, Göteborg, Sweden
E-mail: markus.andersson@chalmers.se

b School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK

c Ian Wark Research Institute, University of South Australia, Mawson Lakes Campus, Adelaide, South Australia 5095, Australia

Abstract

Highly charged microcapsules have been prepared using the internal phase separation technique. The charges are introduced by using ionic dispersants, which have been characterized with respect to surface activity with a quartz crystal microbalance with dissipation monitoring and with optical tensiometry. The long-term stability of the microcapsule suspension without excess dispersant, as well as the stability at high ionic strength, have been investigated. Three types of ionic dispersants have been evaluated: a weak polyacid (poly(methacrylic acid)), a small set of ionic amphiphilic block copolymers of poly(methyl methacrylate)-block-poly(sodium (meth)acrylate) type and an oil-soluble anionic surfactant, sodium 1,5-dioxo-1,5-bis(3,5,5-trimethylhexyloxy)-3-((3,5,5-trimethylhexyloxy)carbonyl)pentane-2-sulfonate, in combination with a water-soluble polycation, poly(diallyldimethylammonium chloride). The block copolymer based microcapsule suspension is characterized by a long-term stability, even at high ionic strength, provided by electrostatic and steric stabilization. The weak polyacid based microcapsule suspension is stable for a few weeks, after which aggregation starts due to desorption of the dispersant. The surfactant–polycation based microcapsules appear to have a multicore morphology in contrast to the weak polyacid or block copolymer based microcapsules, which are core–shell particles.

Graphical abstract: Charged microcapsules for controlled release of hydrophobic actives. Part I: encapsulation methodology and interfacial properties

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Article information

DOI
https://doi.org/10.1039/C2SM27275J
Article type
Paper
Submitted
02 Oct 2012
Accepted
12 Nov 2012
First published
03 Dec 2012

Soft Matter, 2013,9, 1468-1477

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Charged microcapsules for controlled release of hydrophobic actives. Part I: encapsulation methodology and interfacial properties

M. Andersson Trojer, Y. Li, C. Abrahamsson, A. Mohamed, J. Eastoe, K. Holmberg and M. Nydén, Soft Matter, 2013, 9, 1468 DOI: 10.1039/C2SM27275J

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