Tailoring of the interplay of different packing motifs allows to tune the self-assemblies and hierarchies of block copolymers and polymeric complexes. This allows routes to uncommon self-assemblies and even to nanoscale porosity (N. Houbenov et al, Angew. Chem., Int. Ed. 2011, 50, 2516.). However, if the level of frustration becomes excessive, the structure becomes poor. Here we describe two approaches leading to uncommon self-assemblies. The first example deals anionically synthesized polystyrene-block-poly(1,4-isoprene)-block-poly(dimethyl siloxane)-block-poly(tert-butyl methacrylate)-block-poly(2-vinylpyridine) pentablock copolymers (P. Fragouli et al, J. Polym. Sci, A 2008, 46, 3938). Here its self-assembly to form complicated multicompartmental micelles is described based on transmission electron microscopy tomography and several staining protocols (J. Haataja et al, in progress). The second example deals four-arm miktoarm polyethylene glycol polymer that has ammonium chloride end groups. Upon complexing with iodoperfluoroalkanes by halogen bonding, it adopts a particularly well developed lameller order, due to the very high repulsion between the fluorous tails and the hydrophilic polymer, leading to minimized interface area (N. Houbenov et al, Nature Commun, 2014, 5, 4043). In combination with reduced entanglements as allowed by star-shaped polymers in comparison to corresponding linear ones, and the high packing tendency of the fluorous rods, the self-assembly extends from nanometers to millimeters in a common alignment.

Tailoring molecular packing for uncommon polymeric self-assemblies

249th National Meeting (2015)

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