Half-moon morphology

Scanning electron microscopy (SEM) of microcapsules from which HD is extracted have been studied to understand the extent of encapsulation. One-hole, large-hole and half-moon morphologies imply that HD is not encapsulated completely by polymer, whereas a hollow morphology indicates complete encapsulation. Figure 5.8 shows SEM images of polymer microcapsules as a function of HD amount at lower monomer conversion (without DMAEMA). In the absence of DMAEMA, one-hole or... 

When monomers of drastically different solubiUty (39) or hydrophobicity are used or when staged polymerizations (40,41) are carried out, core—shell morphologies are possible. A wide variety of core—shell latices have found appHcation ia paints, impact modifiers, and as carriers for biomolecules. In staged polymerizations, spherical core—shell particles are made when polymer made from the first monomer is more hydrophobic than polymer made from the second monomer (42). When the first polymer made is less hydrophobic then the second, complex morphologies are possible including voids and half-moons (43), although spherical particles stiU occur (44). 

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