Vertically Aligned Nanopillar Arrays with Hard Skins Using Anodic Aluminum Oxide for Nano Imprint Lithography

Abstract

Master molds with nano-pillar structures were fabricated by using anodic aluminum oxide (AAO) for nano-imprint lithography (NIL). The proposed method consists of (1) AAO fabrication, (2) transfer of the thin AAO layer onto a substrate, (3) aluminum sputtering, (4) aluminum melting, and (5) removal of the thin AAO layer. Since the sputtered aluminum penetrated into the porous alumina walls of the AAO template during the melting step, the pillars had skin layers of aluminum/alumina composite which added additional mechanical strength and chemical resistance. The diameter of a pillar in the nano-pillar master mold was larger than that of the hole diameter of the original AAO template because of the hard skin of aluminum/alumina composite layer which covers the pillar surface. The pillar structure could be used as a mold for NIL, resulting in a regular pore array on a polymer film.

One-dimensional polymer nanofiber arrays with high aspect ratio obtained by thermal nanoimprint method

“…Recently, polymer nanostructure improvement with various morphologies has been attracting interest. Nanofibers , nanowires , and nanopillars are prominent structures used for nanotechnology. Various methods have been developed for their fabrication so that clarification of this field has been investigated.…”

Microcantilevers with Nanochannels

“…[16][17][18][19][20] Moreover, replicas of these nanochannels can also be applied in many important fields such as nanoimprint lithography, superhydrophobic surface, and photonic crystals. [21][22][23] Recently, AAO technology has experienced a major technological leap by adopting photolithography. [24][25][26] This combination will result in various MEMS/NEMS structures with nanochannels in the years to come.…”

Multiscale Structures Aggregated by Imprinted Nanofibers for Functional Surfaces

“…Owing to its multiscale structure having a large number of nano-scale pores and micro-scale height, AAO is widely used as the template for fabrication of nanofibers and nanotubes with a high aspect ratio 27,28,29,30 . However, because of the surface tension at such a high aspect ratio, nanofibers tend to easily aggregate 31,32,33 . Existing research has proved that nanofibers having an aspect ratio greater than 15:1 do not stand upright but instead aggregate, whereas those having a ratio less than 5:1 are individually isolated without aggregation 33,34 .…”