Fabrication of macrolens with fully covered nanopillars in large area by air-assisted deformation and nanoimprinting

Abstract

A macrolens with fully covered nanopillars in large area was fabricated by a combination of air-assisted deformation and nanoimprinting. The planar nanopillars were transformed into macrocurved distribution by air-assisted deformation. We tested the nonwetting and antireflectance performance of the fabricated structures and both performances improved by the addition of nanopillars relative to the planar surface. The nanopillars and the curved architecture increased the contact angle by 27 deg and 13 deg, respectively. In addition, the height and diameter of the macrolens could be controlled precisely by the change of the mold size and adjustment of applied negative pressure. Furthermore, the surface reflection was reduced by 1% to 2% over a wavelength range of 500 to 2200 nm by the introduction of gradual index variation. The proposed method is simple, controllable, and has high fabrication efficiency. The macrolens with nanopillars have wide potential applications, such as in optical devices for harsh environments.