| Abstract
| - The self-organization of rotaxane thin films into spatially correlated nanostructures is shown tooccur upon a thermal stimulus. The mechanism of formation of nanostructures and their organization hasbeen investigated using atomic force microscopy, bright field transmission electron microscopy, selectedarea electron diffraction, and molecular mechanics simulations. The evolution of the nanostructures followsa complex pathway, where a rotaxane thin film first dewets from the substrate to form nanosized droplets.Droplets coalesce by ripening, generating spatially correlated motifs. In a later stage, the larger dropletschange shape, nucleate, and coalesce to yield crystallites that grow into larger crystals by incorporatingthe surrounding droplets. The results show the following: (i) the nanostructures represent a metastablestate of a crystallization process; (ii) spatial correlations emerge during ripening, but they are destroyed asstable nuclei are formed and crystallization proceeds to completion; iii) crystallization, either on graphite oramorphous carbon films, leads to a precise basal plane, viz. (010), which has minimum surface energy.The inherent degrees of freedom permitted in the rotaxane architecture favors the re-organization andnucleation of the film in the solid state. Low-energy trajectories leading to crystallites with stable surfacesand minimum energy contact plane are found to occur via concerted, small amplitude, internal motionswithout disruption of packing and intermolecular contacts.
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