The effect of pH on charge, swelling and desorption of the dispersant poly(methacrylic acid) from poly(methyl methacrylate) microcapsules

Markus Andersson Trojer; Anne Wendel; Krister Holmberg; Magnus Nydén

doi:10.1016/j.jcis.2012.02.026

The effect of pH on charge, swelling and desorption of the dispersant poly(methacrylic acid) from poly(methyl methacrylate) microcapsules

J Colloid Interface Sci. 2012 Jun 1;375(1):213-5. doi: 10.1016/j.jcis.2012.02.026. Epub 2012 Feb 23.

Authors

Markus Andersson Trojer¹, Anne Wendel, Krister Holmberg, Magnus Nydén

Affiliation

¹ Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, Göteborg, Sweden. markus.andersson@chalmers.se

PMID: 22405565
DOI: 10.1016/j.jcis.2012.02.026

Abstract

Poly(methyl methacrylate) microcapsules have been prepared using the solvent evaporation technique with poly(methacrylic acid) (PMAA) as dispersant. The charge, swelling and desorption of PMAA from the microcapsules after treating the suspension with base have been followed using microelectrophoresis, X-ray photoelectron spectroscopy and quartz crystal microbalance with dissipation monitoring on model PMMA surfaces. Basic treatment of the microcapsule suspension leads to temporary colloidal stability through the introduction of charges on the PMAA chain. However, the increase in charge causes a continuous desorption of PMAA from the microcapsule surface, eventually leading to aggregation. If instead poly(diallyldimethylammonium chloride) is added to the base treated microcapsule suspension, good colloidal stability is obtained.