Polymer pattern transformation and inorganic polygonal networks driven by thermal degradation process

We describe a simple method to produce novel transformation of polymer pore patterns from circular to noncircular by annealing porous PVA films. These films were prepared by modified microcontact printing (μcp) technique of transferring colloidal crystals onto PVA-coated substrate. Two-dimensional ordered noncircular patterns, such as squares or hexagons depending on the lattice of colloidal templates, were fabricated. The pattern transformation from circular to noncircular is driven by thermal degradation of PVA. Furthermore, inorganic network structures were fabricated by mixing different decomposable inorganic precursors with PVA and using polymer matrix as structure-directing agent in the following pyrolysis process. The organic components of the hybrid film were removed by calcinations and finally inorganic polygonal networks were left on the substrate. These noncircular nanostructures may have unique size- and shape-dependent optical, electronic and magnetic properties.