Fabrication of crystalline assemblies, or superlattices, of 1D nanoscale building blocks has been of great interest because of the collective properties that may result from their uniform arrangements.  To tune the collective properties, the control over not only the symmetry but also the gap between building blocks is crucial. Various assembly methods that utilize enthalpic or entropic interactions, such as solvent evaporation, DNA base-pairing, or charge have been developed to fabricate superlattice structures, as well as strategies based on external magnetic and electric forces. Recently, the depletion interaction has received considerable attention because it is a simple but powerful means to direct and control the self-assembly of anisotropic particles with tunable inter-particle distances. The attractive depletion interaction induced by the depletant is often balanced by the repulsive electrostatic interaction originating from the surface charge of the particles.In this presentation, we will show that a wide range of inter-particle distances between rod-like particles can be achieved by employing rigid polymers as depletants; the lattice parameter, d , of the superlattice of rod-like particles can be tuned from approximately 1 to 5 times the diameter, D ,of the rod-like particles. Notably, we found that depletion alone cannot explain these large inter-particle distances, and propose as second mechanism by which the polymers are able to induce self-assembly. In addition, we show that the inter-particle distance can be controlled reversibly in response to external stimuli such as temperature by employing rigid-gel forming polymers.

Stimulus-responsive superlattice assembled and tuned by polymer

246th National Meeting (2013)

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