Eur. Phys. J. E 5, 13-20
Shrinking of ultrathin polyelectrolyte multilayer capsules upon annealing: A confocal laser scanning microscopy and scanning force microscopy study
S. Leporatti1, C. Gao1, 2, A. Voigt1, 3, E. Donath1 and H. Möhwald11 Max-Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
2 Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P.R. China
3 Institute of Transfusion Medicine Medical Faculty Charité, Humboldt University of Berlin, 10098 Berlin, Germany
edwin.donath@mpikg-golm.mpg.de
(Received 20 January 2000 )
Abstract
Heating-induced morphological changes of micrometer size capsules prepared by step-wise
deposition of oppositely charged polyelectrolytes onto melamine formaldehyde (MF) latex
particles and biological cells with subsequent dissolution of the core have been investigated
by confocal laser scanning microscopy (CLSM) and scanning force microscopy (SFM). For
poly(styrenesulfonate-Na salt)/poly(allylamine hydrochloride) polyelectrolyte capsules a
remarkable heating-induced shrinking is observed. An increase of the wall thickness
corresponding to the capsule diameter decrease is found. The morphology of these
microcapsules after temperature treatment is characterized. The thickening of the
polyelectrolyte multilayer is interpreted in terms of a configurational entropy increase via
polyanion-polycation bond rearrangement.
61.16.Ch - Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc..
61.41.+e - Polymers, elastomers, and plastics.
68.60.Dv - Thermal stability; thermal effects.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001