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.

Original languageEnglish
Pages (from-to)1222-1232
Number of pages11
JournalMicroscopy and Microanalysis
Volume22
Issue number6
DOIs
Publication statusPublished - 1 Dec 2016

    Research areas

  • EELS, electron tomography, in situ mechanical TEM, melamine formaldehyde, transmission electron microscopy

ID: 29952430