“…Airbrushing can provide one promising solution for continuous and uniform resin coating over a large-area substrate, prior to feeding it to the mold-contacting zone in UV NIL. Koo et al demonstrated the uniform airbrushing of UV-curable resin on a substrate that was continuously fed to the R2R UV NIL [ 162 ]. Controlling the resin concentration and airbrushing conditions can enable residual layer-controlled R2R NIL in a continuous manner without resorting to spin-coating or other non-continuous resin coating methods [ 163 ].…”
Metasurfaces have shown promising potential to miniaturize existing bulk optical components thanks to their extraordinary optical properties and ultra-thin, small, and lightweight footprints. However, the absence of proper manufacturing methods has been one of the main obstacles preventing the practical application of metasurfaces and commercialization. Although a variety of fabrication techniques have been used to produce optical metasurfaces, there are still no universal scalable and high-throughput manufacturing methods that meet the criteria for large-scale metasurfaces for device/product-level applications. The fundamentals and recent progress of the large area and high-throughput manufacturing methods are discussed with practical device applications. We systematically classify various top-down scalable patterning techniques for optical metasurfaces: firstly, optical and printing methods are categorized and then their conventional and unconventional (emerging/new) techniques are discussed in detail, respectively. In the end of each section, we also introduce the recent developments of metasurfaces realized by the corresponding fabrication methods.
“…Airbrushing can provide one promising solution for continuous and uniform resin coating over a large-area substrate, prior to feeding it to the mold-contacting zone in UV NIL. Koo et al demonstrated the uniform airbrushing of UV-curable resin on a substrate that was continuously fed to the R2R UV NIL [ 162 ]. Controlling the resin concentration and airbrushing conditions can enable residual layer-controlled R2R NIL in a continuous manner without resorting to spin-coating or other non-continuous resin coating methods [ 163 ].…”
Metasurfaces have shown promising potential to miniaturize existing bulk optical components thanks to their extraordinary optical properties and ultra-thin, small, and lightweight footprints. However, the absence of proper manufacturing methods has been one of the main obstacles preventing the practical application of metasurfaces and commercialization. Although a variety of fabrication techniques have been used to produce optical metasurfaces, there are still no universal scalable and high-throughput manufacturing methods that meet the criteria for large-scale metasurfaces for device/product-level applications. The fundamentals and recent progress of the large area and high-throughput manufacturing methods are discussed with practical device applications. We systematically classify various top-down scalable patterning techniques for optical metasurfaces: firstly, optical and printing methods are categorized and then their conventional and unconventional (emerging/new) techniques are discussed in detail, respectively. In the end of each section, we also introduce the recent developments of metasurfaces realized by the corresponding fabrication methods.
“…Figure 1A describes the rollto-roll imprinting process on the PET film. First, we wrapped a cylindrical roll with an imprinting mold for stamping nanoarchitecture on the PET film coated with UV-curable polymer resin using an airbrush coating process (Koo et al, 2016). As the resin-coated PET films pass through the cylindrical roller, UV light cures the imprinted film at the outlet.…”
Section: Resultsmentioning
confidence: 99%
“…Au LSPR strip was fabricated using roll-to-roll nanoimprint lithography (Koo et al, 2016;Wi et al, 2017). First, nanograting structures were fabricated with polyurethane acrylate (PUA) on PET film using a 200 nm-pitch and 100 nm-height silicon master.…”
Localized surface plasmon resonance (LSPR) is a powerful platform for detecting biomolecules including proteins, nucleotides, and vesicles. Here, we report a colloidal gold (Au) nanoparticle-based assay that enhances the LSPR signal of nanoimprinted Au strips. The binding of the colloidal Au nanoparticle on the Au strip causes a red-shift of the LSPR extinction peak, enabling the detection of interleukin-10 (IL-10) cytokine. For LSPR sensor fabrication, we employed a roll-to-roll nanoimprinting process to create nanograting structures on polyethylene terephthalate (PET) film. By the angled deposition of Au on the PET film, we demonstrated a double-bent Au structure with a strong LSPR extinction peak at ∼760 nm. Using the Au LSPR sensor, we developed an enzyme-linked immunosorbent assay (ELISA) protocol by forming a sandwich structure of IL-10 capture antibody/IL-10/IL-10 detection antibody. To enhance the LSPR signal, we introduced colloidal Au nanocube (AuNC) to be cross-linked with IL-10 detection antibody for immunogold assay. Using IL-10 as a model protein, we successfully achieved nanomolar sensitivity. We confirmed that the shift of the extinction peak was improved by 450% due to plasmon coupling between AuNC and Au strip. We expect that the AuNC-assisted LSPR sensor platform can be utilized as a diagnostic tool by providing convenient and fast detection of the LSPR signal.
“…Notably, this is valid as long as the resin concentration is within a proper range; too thick resin causes an uneven surface while too thin resin cannot form a continuous thin film after PGMEA is dried. In our case, an adequate concentration range of SSQ for making uniform thin films and later well-imprinted patterns is found to be between 5 and 10 wt% [12]. We focus on the two cases, 5 and 10 wt% with maximum propellant air pressure of 0.15 MPa, for parametric investigations hereafter, unless otherwise specified.Fig.…”
Section: Resultsmentioning
confidence: 99%
“…A UV-curable polymeric resin is diluted in a volatile solvent for smooth flowing, which is airbrushed over the substrate to leave a uniform thin resin film behind. This quick process is well-suited to the continuous and high-speed R2R NIL; we first review that a uniform nanoscale line (nanograting) pattern can be faithfully fabricated by conducting R2R NIL with a flexible nanograting mold onto the airbrushed resin films based on our previous work [ 12 ]. By modulating the resin concentration and airbrushing time, the initial thin film thickness as well as the residual layer thickness (RLT) of the nanopatterns created by R2R NIL can be readily controlled.…”
We present a facile and scalable coating method based on controlled airbrushing, which is suitable for conformal resin coating in continuous roll-to-roll (R2R) nanoimprint lithography (NIL) process. By controlling the concentration of UV-curable polymeric resin with mixing the volatile solvent and its airbrushing time, the coated resin film thickness can be readily tuned. After R2R NIL using a flexible nanoscale line pattern (nanograting) mold is conducted upon the airbrushed resin film, a large-area uniform nanograting pattern is fabricated with controlled residual layer thickness (RLT) based on the initial film thickness. We investigate the faithful airbrushing condition that can reliably create the uniform thin films as well as various nanopatterns with controlled morphologies. Using more diluted resin and shorter airbrushing time can reduce the RLTs favourably for many applications, yet is apt to induce the nanoscale pores and discontinued lines. We also discuss how to further improve the quality and scalability of resin airbrushing and its potential applications particularly requiring high-speed and conformal coating on highly topographic and flexible surfaces.
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