Dendrimers are nanosized molecules with spherical shape, regular branching, and multiple functionalities. These molecules are promising nanomaterials as drug carriers, nano reactors, catalyst carriers, rheological modifiers, and so on. The traditional way of dendrimer synthesis is, however, laborious. Recently, we developed a synthetic approach for dendrimer-like polymers through anionic polymerization. The synthetic procedure is constituted by iterative steps of anionic polymerization and reaction. Therefore, living polystyrenyllithium, possessing ca. 10 p-vinylethyl styrenic units at the w-end (w-vinyl-PSLi), was coupled to a trifunctional core, 1,3,5-tribromomethyl benzene, to form the first generation (three-arm star). After transforming the vinyl groups into chlorosilane moieties by hydrosilylation, the same w-vinyl-PSLi chains were attached again to yield the second generation (ca. 30 arms). Repeating the process 3-4 times yielded dendrimer-like polystyrenes with molecular weight up to tens of millions Da and the size up to tens or nearly hundred of nanometers. The advantage of the present approach is the synthetic efficiency. The molecular weight grow fast with generation number. It is also easy functionalize the dendritic products with various functionalities or functional polymer segments such as poly(p-tert-butoxy)styrene, poly(a-methyl)stryene (G4-PaMeSt), poly(meth)acrylates (G4-PtBMA), poly(ethylene oxide), and poly(2-vinylpyridine) (G4-P2VP) through proper reactions. These products were used as model molecules for the investigation of various properties such as rheology, unimolecular morphology, unimolecualr micelle, and as nanoreactors.

Dendritic molecular nanospheres by living anionic polymerization

256th National Meeting (2018)

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