Single-imprint moth-eye anti-reflective and self-cleaning film with enhanced resistance

Abstract

Antireflective transparent materials are essential for a myriad of applications to allow for clear vision and efficient light transmission. Despite the advances, efficient and low cost solutions to clean antireflective surfaces have remained elusive. Here, we present a practical approach that enables the production of antireflective polymer surfaces based on moth-eye inspired features incorporating photoinduced self-cleaning properties and enhanced mechanical resistance. The methodology involves the fabrication of sub-wavelength moth-eye nanofeatures onto transparent surface composite films in a combined processing step of nanoparticle coating and surface nanoimprinting. The resulting surfaces reduced the optical reflection losses from values of 9% of typical PMMA plastic films to an optimum value of 0.6% in the case of double-sided moth-eye nanoimprinted films. The composite moth-eye topography also showed an improved stiffness and scratch resistance. This technology represents a significant advancement not limited by scale, for the development of antireflective films for low cost application products.

Methylated Silica Surfaces Having Tapered Nipple-Dimple Nanopillar Morphologies as Robust Broad-Angle and Broadband Antireflection Coatings

“…This also suggests that the intrinsic scattering from the underlying glass support is actually the main limiting factor for light transmission of the double face ARC shown in Figure 2 A). These performances in transmission are in line with those reported for double-side coated graded ARC systems 30,31,32,33 . A graded ARC from a similar sol-gel hybrid material was reported 28 , exhibiting an excellent ARC effect close to 0% in reflection (at ~560 nm) with a fluctuation of 3% in the full visible range.…”

Bioinspired antireflective flexible films with optimized mechanical resistance fabricated by roll to roll thermal nanoimprint

“…Above the glass transition, the maximum height of the nanofeatures remains approximately constant in all experiments and the topmost protruding nanocones with better replica accuracy were obtained with height values slightly above 300 nm at T g + 35 °C, which is close to that of the moth-eye patterns of Ni mold (see Figure S1 in Supporting Information). This result indicates that at a temperature above T g , the web speed of 0.02 m•min −1 is slow enough to allow for the viscous polymer flow to reach a comparable level of cavity filling into the mold, rendering a mean nanocone height equivalent to that obtained under conventional thermal NIL conditions 28 .…”

“…Evaluation of the mechanical properties were carried out by nanoindentation and nanoscratch tests 28,36,37 . Figure 3a shows the characteristic curves corresponding to the load-unload nanoindentation cycles upon application of a monotonically increasing nanoindentation load up to a maximum of 200 µN on the different substrates under study.…”

Multilevel Hierarchical Topographies by Combined Photolithography and Nanoimprinting Processes To Create Surfaces with Controlled Wetting

“…47 Working molds of PDMS with the moth-eye topography and 500 nm period microridges were prepared by replicating a master nickel (HT-AR-02, Temicon) and a silicon (LightSmyth Technologies) mold, respectively, by using the procedure described elsewhere. 48 For the fabrication of the hierarchical multilevel structures, the first step was the production of the two-level second-order hierarchical h-PDMS working mold. The substrates obtained on the sequential replication steps are illustrated by SEM images in Figure S2.…”