Keywords: nanoimprint lithography, 2D, 3D, hierarchical structures, polymers, polymer microstructures, polymer nanostructures, nanotechnology, reversal imprinting, combinatorial mould imprinting, sequential imprinting, colloidal self-assembly
Complex and useful polymer micro- and nanostructures via nanoimprint lithography
This paper presents an overview on three major fabrication techniques developed in our laboratory for achieving complex polymeric structures using nanoimprint lithography (NIL), namely reversal imprinting, combinatorial-mould imprinting and sequential imprinting. The key strategy employed by all three techniques is the use of conventional two-dimensional (2D) molds to achieve greater degrees of complexity than are ordinarily achievable with conventional imprinting techniques. For example, reversal imprinting combined with colloidal self-assembly allows for structures that have variations with depth as well as scale. Combinatorial-mould imprinting enables the fabrication of three-dimensional (3D) structures that have variations in length, width as well as depth. Sequential imprinting enables hierarchical structures that have scale-dependent variations and complexity. 3D structures, hierarchical structures, and combinations thereof are obtained in fewer processing steps and without the use of a sacrificial component or process.