Depletion-driven morphological transitions in hexagonal crystallites of virus rods
Résumé
The assembly of nanometer-sized building blocks into complex morphologies is not only of 11 fundamental interest but also plays a key role in material science and nanotechnology. We show 12 that the shape of self-assembled superstructures formed by rod-shaped viruses can be controlled 13 by tuning the attraction via the depletion interaction between the rods. Using non-adsorbing 14 polymers as a depleting agent, we demonstrate that a hierarchical unidimensional self-15 organization into crystalline clusters emerges progressively upon increasing depletion attraction 16 and enhanced growth kinetics. We observe a polymorphic change proceeding from two-17 dimensional (2D) crystalline monolayers at weak depletion to one-dimensional (1D) columnar 18 fibers at strong depletion, via the formation of smectic fibrils at intermediate depletion strength. A 19 simple theory for reversible polymerization enables us to determine the typical bond energy 20 between monomeric units making up the smectic fibrils. We also demonstrate that gentle flow-21 assistance can be used to template filament-like structures into highly aligned supported films. 22 Our results showcase a generic bottom-up approach for tuning the morphology of crystalline 23 superstructures through modification of the interaction between non-spherical building blocks. 24 This provides a convenient pathway for controlling self-organization, dimensionality and 25 structure-formation of anisotropic nanoparticles for use in nanotechnology and functional 26 materials. 27 28 29 30
Domaines
Matière Molle [cond-mat.soft]
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