Formation and mechanical characterization of aminoplast core/shell microcapsules

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Melanie Pretzl - , University of Bayreuth (Author)
  • Martin Neubauer - , University of Bayreuth (Author)
  • Melanie Tekaat - , University of Bayreuth (Author)
  • Carmen Kunert - , University of Bayreuth (Author)
  • Christian Kuttner - , University of Bayreuth (Author)
  • Géraldine Leon - , Firmenich SA (Author)
  • Damien Berthier - , Firmenich SA (Author)
  • Philipp Erni - , Firmenich SA (Author)
  • Lahoussine Ouali - , Firmenich SA (Author)
  • Andreas Fery - , University of Bayreuth (Author)

Abstract

This work aims at establishing a link between process conditions and resulting micromechanical properties for aminoplast core/shell microcapsules. The investigated capsules were produced by the in situ polymerization of melamine formaldehyde resins, which represents a widely used and industrially relevant approach in the field of microencapsulation. Within our study, we present a quantitative morphological analysis of the capsules size and shell thickness. The diameter of the investigated capsules ranged from 10 to 50 μm and the shell thickness was found in a range between 50 and 200 nm. As key parameter for the control of the shell thickness, we identified the amount of amino resin per total surface area of the dispersed phase. Mechanical properties were investigated using small deformations on the order of the shell thickness by atomic force microscopy with a colloidal probe setup. The obtained capsule stiffness increased with an increasing shell thickness from 2 to 30 N/m and thus showed the same trend on the process parameters as the shell thickness. A simple analytical model was adopted to explain the relation between capsules geometry and mechanics and to estimate the elastic modulus of the shell about 1.7 GPa. Thus, this work provides strategies for a rational design of microcapsule mechanics.

Details

Original languageEnglish
Pages (from-to)2940-2948
Number of pages9
JournalACS Applied Materials and Interfaces
Volume4
Issue number6
Publication statusPublished - 27 Jun 2012
Peer-reviewedYes
Externally publishedYes

Keywords

ASJC Scopus subject areas

Keywords

  • compression behavior, controlled release, elastic properties, emulsions, hollow polymer shells, melamine formaldehyde capsules, stability