Facile Fabrication Of Oriented Anisotropic Particle Arrays Via Solvent Vapor Treatment

The self-assembly of nanobowl into ordered arrays also has applications in low cost, large area micro- and nanofabrication, for example, in microlens arrays and micro conductor. However, there are a limited number of methods to have a controlled orientation of anisotropic particles, so we need a facile and reproducible process for the formation of oriented anisotropic particles. Nonspherical-based colloidal crystals have been desired as photonic materials because of the enhanced light control provided by the anisotropy of structure. For example, the structure was found to lift the symmetry induced degeneracy of photonic bands, leading to complete photonic band gaps in hexagonal close-packed structure. Although the magnetic and electric fields have been demonstrated to successfully induce the self-assembly of asymmetric particles, which were first prepared by certain specific methods, field-induced particle interactions and hence the resulting ordered arrays of asymmetric particles are strongly dependent on the strength of the external field applied, as well as the size, aspect ratio, and polarizability of the particles, which is not favorable for wide-ranging applications. To overcome these restrictions, we need method to create large-area, ordered arrays of anisotropic non-spherical particles.The two step dispersion polymerization has been used in order to prepare PS-DVB core-shell particles in this paper, assemble the particles into hexagonal close-packed structure with the help of needle, then ordered nanobowl array or ordered nonspherical particles array can be obtained after annealing in solvent vapor. Here we report a facile and reproducible process for the formation of oriented nanobowl array or ordered nonspherical particles array respectively.In the progress of synthesis of PS-DVB particles, the hydrophobicity of particles, and the degree of cross-linking or the thickness of shell can be adjusted by the factors of the time of adding reagent and the amount of DVB respectively. In the progress of annealing in solvent vapor, the morphology of particles can be adjusted by the factors of the hydrophobicity of particles, the degree of cross-linking and the type or amount of solvent. The ordered nanobowl array is easily observed after annealing the particles with low degree of cross-linking, and the depth of buckling is linked with annealing time. The ordered nonspherical particles array is easily observed after annealing the particles with proper hydrophobicity and degree of cross-linking, and the morphology of particles can be adjusted by the factors of the annealing time and solvent.