title: Melamine-Formaldehyde Microcapsules: Micro- and Nanostructural Characterization with Electron Microscopy.
abstract: A systematic study has been carried out to compare the surface morphology, shell thickness, mechanical properties, and binding behavior of melamine-formaldehyde microcapsules of 5-30 μm diameter size with various amounts of core content by using scanning and transmission electron microscopy including electron tomography, in situ nanomechanical tensile testing, and electron energy-loss spectroscopy. It is found that porosities are present on the outside surface of the capsule shell, but not on the inner surface of the shell. Nanomechanical tensile tests on the capsule shells reveal that Young's modulus of the shell material is higher than that of bulk melamine-formaldehyde and that the shells exhibit a larger fracture strain compared with the bulk. Core-loss elemental analysis of microcapsules embedded in epoxy indicates that during the curing process, the microcapsule-matrix interface remains uniform and the epoxy matrix penetrates into the surface micro-porosities of the capsule shells.
authors.affiliation: 1Electron Microscopy for Materials Science (EMAT),University of Antwerp,Groenenborgerlaan 171,2020 Antwerp,Belgium.
authors.forename: Hamed
authors.initials: H
authors.lastname: Heidari
authors.affiliation: 2Department of Organic and Macromolecular Chemistry,Polymer Chemistry Research Group,Ghent University,Krijgslaan 281 S4,9000 Ghent,Belgium.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Rivero
authors.affiliation: 1Electron Microscopy for Materials Science (EMAT),University of Antwerp,Groenenborgerlaan 171,2020 Antwerp,Belgium.
authors.forename: Hosni
authors.initials: H
authors.lastname: Idrissi
authors.affiliation: 1Electron Microscopy for Materials Science (EMAT),University of Antwerp,Groenenborgerlaan 171,2020 Antwerp,Belgium.
authors.forename: Dhanya
authors.initials: D
authors.lastname: Ramachandran
authors.affiliation: 2Department of Organic and Macromolecular Chemistry,Polymer Chemistry Research Group,Ghent University,Krijgslaan 281 S4,9000 Ghent,Belgium.
authors.forename: Seda
authors.initials: S
authors.lastname: Cakir
authors.affiliation: 1Electron Microscopy for Materials Science (EMAT),University of Antwerp,Groenenborgerlaan 171,2020 Antwerp,Belgium.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Egoavil
authors.affiliation: 1Electron Microscopy for Materials Science (EMAT),University of Antwerp,Groenenborgerlaan 171,2020 Antwerp,Belgium.
authors.forename: Mert
authors.initials: M
authors.lastname: Kurttepeli
authors.affiliation: 5Research Group Electrochemical and Surface Engineering (SURF),Department of Materials and Chemistry,Vrije Universiteit Brussel,Pleinlaan 2,1050 Brussels,Belgium.
authors.forename: Amandine C
authors.initials: AC
authors.lastname: Crabbé
authors.affiliation: 5Research Group Electrochemical and Surface Engineering (SURF),Department of Materials and Chemistry,Vrije Universiteit Brussel,Pleinlaan 2,1050 Brussels,Belgium.
authors.forename: Tom
authors.initials: T
authors.lastname: Hauffman
authors.affiliation: 5Research Group Electrochemical and Surface Engineering (SURF),Department of Materials and Chemistry,Vrije Universiteit Brussel,Pleinlaan 2,1050 Brussels,Belgium.
authors.forename: Herman
authors.initials: H
authors.lastname: Terryn
authors.affiliation: 2Department of Organic and Macromolecular Chemistry,Polymer Chemistry Research Group,Ghent University,Krijgslaan 281 S4,9000 Ghent,Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Du Prez
authors.affiliation: 1Electron Microscopy for Materials Science (EMAT),University of Antwerp,Groenenborgerlaan 171,2020 Antwerp,Belgium.
authors.forename: Dominique
authors.initials: D
authors.lastname: Schryvers
keywords: EELS; electron tomography; in situ mechanical TEM; melamine formaldehyde; transmission electron microscopy