Core-crosslinked nanostructures

Figure 6.4 The preparation of nanostructured materials in solution evolves from (a) the classic examples of suspension, dispersion, or emulsion polymerization, to the methods that include the covalent crosslinking of select domains within supramolecular polymer assemblies (b) core crosslinking of polymer micelles (c) shell crosslinking of polymer micelles (SCKs) (d) nanocages from core-eroded SCKs (e) shaved hollow nanospheres from outer shell/core-eroded vesicles.

Figure 6.5 Illustrations of nanoscale spherical assemblies resulting from block copolymer phase separation in solution are shown, along with the chemical compositions that have been employed to generate each of the nanostructures (a) core crosslinked polymer micelles (b) shell crosslinked polymer micelles (SCKs) with glassy cores (c) SCKs with fluid cores (d) SCKs with crystalline cores (e) nanocages, produced from removal of the core of SCKs (f) SCKs with the crosslinked shell shielded from solution by an additional layer of surface-attached linear polymer chains (g) crosslinked vesicles (h) shaved hollow nanospheres produced from cleavage of the internally and externally attached linear polymer chains from the structure of (g)...

The new connective sites provide the opportunity to destroy or disconnect other regions of the nanostructure without destruction of the entire nanoscale entity. This was demonstrated by the excavation of the core of shell crosslinked polymer micelles, by the removal of the colloid from colloidally templated... 

All of the reported crosslinking techniques are very efficient and generate robust phase-separated nanostructures (Figure 17.8) (Read and Armes, 2007). The stabilization methodologies all allow for the complete protection of the core or bilayer domain by the uniform stabilized shell layer, while maintaining the desired nanoscale particle diameters with narrow size distributions (with distributions of around 1-5 nm) - thus providing a confined environment within the core or bilayer domain in which reagents can be sequestered. 

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