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Creators/Authors contains: "Cheng, Stephen Z. D."

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  1. Abstract Three sets of polyoxometalate (POM)‐based amphiphilic hybrid macromolecules with different rigidity in their organic tails are used as models to understand the effect of molecular rigidity on their possible self‐recognition feature during self‐assembly processes. Self‐recognition is achieved in the mixed solution of two structurally similar, sphere‐rigid T‐shape‐linked oligofluorene(TOF4) rod amphiphiles, with the hydrophilic clusters being Anderson (Anderson‐TOF4) and Dawson (Dawson‐TOF4), respectively. Anderson‐TOF4is observed to self‐assemble into onion‐like multilayer structures and Dawson‐TOF4forms multilayer vesicles. The self‐assembly is controlled by the interdigitation of hydrophobic rods and the counterion‐mediated attraction among charged hydrophilic inorganic clusters. When the hydrophobic blocks are less rigid, e.g., partially rigid polystyrene and fully flexible alkyl chains, self‐recognition is not observed, attributing to the flexible conformation of hydrophobic molecules in the solvophobic domain. This study reveals that the self‐recognition among amphiphiles can be achieved by the geometrical limitation of the supramolecular structure due to the rigidity of solvophobic domains. 
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  2. Abstract Self‐assembled nanostructures of rod‐like molecules are commonly limited to nematic or layered smectic structures dominated by the parallel arrangement of the rod‐like components. Distinct self‐assembly behavior of four categories of dendritic rods constructed by placing a tri(hydroxy) group at the apex of dendritic oligo‐fluorenes is observed. Designed hydrogen bonding and dendritic architecture break the parallel arrangement of the rods, resulting in molecules with specific (fan‐like or cone‐like) shapes. While the fan‐shaped molecules tend to form hexagonal packing cylindrical phases, the cone‐shaped molecules could form spherical motifs to pack into various ordered structures, including the Frank–Kasper A15 phase and dodecagonal quasicrystal. This study provides a model system to engineer diverse supramolecular structures by rod‐like molecules and sheds new light into the mechanisms of the formation of unconventional spherical packing structures in soft matter. 
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