[
    {
        "id": 1,
        "chunk": "# ADVANCED MATERIALS  \n\nSupporting Information  \n\nfor Adv. Mater., DOI: 10.1002/adma.202002710  \n\nWet-Style Superhydrophobic Antifogging Coatings for Optical Sensors  \n\nJongsun Yoon, Min Ryu, Hyeongjeong Kim, Gwang-Noh Ahn, Se-Jun Yim, Dong-Pyo Kim,\\* and Hyomin Lee\\*  \n\nCopyright WILEY-VCH Verlag GmbH & Co. KGaA, 69469 Weinheim, Germany, 2020.",
        "category": " References"
    },
    {
        "id": 2,
        "chunk": "# Supporting Information",
        "category": " References"
    },
    {
        "id": 3,
        "chunk": "# Wet-Style Superhydrophobic Antifogging Coatings for Optical Sensors  \n\nJongsun Yoon, Min Ryu, Hyeongjeong Kim, Gwang-Noh Ahn, Se-Jun Yim, Dong-Pyo Kim\\*, and Hyomin Lee\\*",
        "category": " Abstract"
    },
    {
        "id": 4,
        "chunk": "# WILEY-VCH",
        "category": " References"
    },
    {
        "id": 5,
        "chunk": "# Experimental Section",
        "category": " Materials and methods"
    },
    {
        "id": 6,
        "chunk": "# Materials  \n\nChitosan (CHI, low molecular weight), Carboxymethyl cellulose (CMC, $\\mathrm{Mw}=250{,}000\\ \\mathrm{g}$ $\\mathrm{mol^{-1}}.$ ), Cationic silica nanoparticles LUDOX® CL ( $30\\mathrm{wt}\\%$ $\\mathrm{SiO}_{2}$ suspension in water, average particle size of $12\\ \\mathrm{nm}$ , and specific surface area of $220{\\mathrm{~m}}^{2}{\\mathrm{~g}}^{-1}.$ ), Anionic silica nanoparticles LUDOX® HS-40 ( $40\\ \\mathrm{wt}\\%$ $\\mathrm{SiO}_{2}$ suspension in water, average particle size of $12\\ \\mathrm{nm}$ , and specific surface area of $220{\\mathrm{~m}}^{2}{\\mathrm{~g}}^{-1}.$ ), Silicone oil (viscosity $10~\\mathrm{cSt}$ at $25~^{\\circ}\\mathrm{C}$ ), Acetic acid, and 2-Hydroxy-2-methylpropiophenone (Darocur 1173) were purchased from Sigma-Aldrich (Korea). Negative photoresist (SU-8 50, Microchem), Perfluoropolyether (PFPE)-urethane methacrylate (Fluorolink® MD700, Solvay), and Polydimethylsiloxane (PDMS, Sylgard® 184, Dow Corning) were used for lithography. Sand (40-100 mesh) was purchased from Acros Organics. Glass slides $76\\times26\\times1~\\mathrm{mm}$ ) were purchased from Marienfeld.  \n\nPolymer-Silica Nanocomposite Fabrication via Layer-by-Layer Assembly: Sequential stacking of polymer and nanoparticle layers were performed using a StratoSequence 8 spin dipper (nanoStrata Inc.), controlled by StratoSmart operating software. The concentrations of CHI, CMC, positive charged $\\mathrm{SiO}_{2}$ , and negative charged $\\mathrm{SiO}_{2}$ in the dipping solutions were 1 $\\mathrm{mg\\ml^{-1}}$ , $1~\\mathrm{mg~ml^{-1}}$ , $0.03\\%$ (w/w), and $0.03\\%$ (w/w), respectively. For CHI, $0.3\\%$ (v/v) acetic acid (Sigma-Aldrich) was added prior to dissolving the polymer and was filtered with $5~{\\upmu\\mathrm{m}}$ pore filter (Millex®) after stirring overnight. Deionized water ( $18.2~\\mathrm{M}\\Omega\\cdot\\mathrm{cm}$ at $25~^{\\circ}\\mathrm{C}$ ) was used for all aqueous solutions. The dipping time in each solutions was $10~\\mathrm{min}$ followed by three rinsing steps (2, 1, and $1\\mathrm{min}^{\\cdot}$ ) in deionized water. The polymeric reservoir, (CHI/CMC)n ( $\\mathrm{\\dot{n}=}$ number of bilayers) was produced by alternately dipping in CHI and CMC solutions with rinsing steps in between. The polymer-silica nanocomposite was prepared by additionally depositing two complementary interacting nanoparticles on the polymeric reservoir.",
        "category": " Materials and methods"
    },
    {
        "id": 7,
        "chunk": "# WILEY-VCH  \n\nCold-Fog Transition Test: The cold-fog transition test described in Figure 1e and Figure 1f was performed by incubating glasses coated with various types of films in a $-15^{\\circ}\\mathrm{C}$ freezer for 12 hours and subsequent transfer to ambient lab conditions ( $21~^{\\circ}\\mathrm{C}$ , $35\\%$ RH). The cold-fog transition test described in Figure 3b and Figure 3e was conducted by contacting the coated glasses with a Peltier plate $\\left(-20^{\\circ}\\mathrm{C}\\right)$ for 1 minute and exposure to an ambient condition $(25^{\\circ}\\mathrm{C}$ , $22\\%$ RH) for 10 seconds. The optical photographs were obtained by a digital microscope (AM4113, Dino-Lite). For the observation of surface-induced fog, an inverted microscope (Eclipse Ti2, Nikon) was used. The cold-fog transition test described in Figure S5 was performed by incubating micro-pillar assembled polymer-silica nanocomposite in a $4~^{\\circ}\\mathrm{C}$ freezer for 1 hour and subsequent transfer to a temperature and humidity condition of $50~^{\\circ}\\mathrm{C}$ , $55\\%$ RH.  \n\nLow Surface Energy Micro-Pillar Array Transfer on the Polymer-Silica Nanocomposite via Two-Step Lithography: To transfer the micro-pillar array, SU-8 pillar array was fabricated using typical lithography with a negative photoresist (SU-8 50). PDMS was poured onto the master and cured in an oven set at $70~^{\\circ}\\mathrm{C}$ for 3 hours. Then, photocurable PFPE polymer precursor containing $4\\%$ (w/w) Darocur 1173 was poured into the PDMS microwell and the excess was removed using a razorblade. Prior to attachment and curing, the polymer-silica nanocomposite was infused with a silicone oil to avoid PFPE film formation on the polymersilica nanocomposite. UV with an intensity of $20\\mathrm{mW}\\mathrm{cm}^{-2}$ was irradiated for 5 min to induce photocuring of the independent PFPE pillars. The residue was washed off with acetone.  \n\nOther Measurements: The thickness of the films were characterized using profilometry (Dektak XT, Bruker). The Fourier transform infrared (FT-IR) spectra were collected using FT-IR spectroscopy (PerkinElmer) in transmittance mode. The X-ray photoelectron spectroscopy (XPS) spectra were obtained at the 4D beamline in the Pohang Accelerator",
        "category": " Materials and methods"
    },
    {
        "id": 8,
        "chunk": "# WILEY-VCH  \n\nLaboratory (PAL). The refractive index of the polymer and the silica layer was measured using spectroscopic ellipsometry (M-2000, J.A. Woollam). The water contact angles were measured using goniometry (SmartDrop, FemtoBiomed Inc.). The transmission spectra of the substrates were measured by spectrophotometer (UV-1800, Shimadzu) with a scanning rate of $50\\mathrm{nm\\sec^{-1}}$ . To demonstrate the utility of the wet-style superhydrophobic antifogging coating, an image sensor (Pixy2) was used to identify the specific colors in various simulated conditions.  \n\n![](images/f0bbcdb774ad87d3f5b6ad0ddd0052fc2563f2de9dc8421db5e4b36d32bc7e57.jpg)  \nFigure S1. (a) The thickness of the polymeric reservoir with respect to the number of bilayers (n) of (CHI/CMC). (b) Transmission spectra of the polymeric reservoir, $(\\mathrm{CHI/CMC)_{n}}$ .  \n\n![](images/22e5099fdd4a40e4ef5ba334544127873aedfa5dd9a3e5c6fcdb1e309e0e1813.jpg)  \nFigure S2. XPS spectra of the polymer-silica nanocomposite (blue line) and polymeric reservoir (green line) (a) O 1s spectra, (b) Si 2p spectra.  \n\n![](images/03f412d4f5145d728b4ee93f7ddd6dcb07ee51ec49d535c3ae12c449834d3f2c.jpg)  \nFigure S3. (a) The thickness of the polymer-silica nanocomposites with respect to the number of bilayers (n) of $\\mathrm{(SiO_{2}/S i O_{2}}$ ). (b) Transmission spectra of the polymer-silica nanocomposites, $\\mathrm{(CHI/CMC)_{30}(S i O_{2}/S i O_{2})_{n}}$ .  \n\n![](images/bdb7317c6108b493c24e95ceea72fa850795b76575bb4e61b7088a7b87de628c.jpg)  \nFigure S4. FT-IR spectra of the (a) individual materials used in the wet-style superhydrophobic antifogging coating and (b) the coating in each step during the assembly.  \n\n![](images/9fe424ea88d0358ed1f3c7d52f292833e6982ea21b2be3d55c83dfdaac5b9607.jpg)  \nFigure S5. (a) A plot showing the water advancing (black bar), and receding (red bar) contact angles of the wet-style superhydrophobic antifogging coatings after exposure to various solvents for 1 hour (micro-pillar interval/diameter value of 4.0). (b) Optical photographs taken after transfer to an environmental chamber equilibrated at $50~^{\\circ}\\mathrm{C}$ , $55\\%$ RH from a $4^{\\circ}\\mathrm{C}$ refrigerator for the wet-style superhydrophobic antifogging coatings treated with various solvents. The scale bar is $1\\mathrm{cm}$ .  \n\n![](images/596ec72813e8a38ba027cab08fc9bf65cfec1b2878c95fc93248bab072c0e5d5.jpg)  \nFigure S6. Scanning electron microscopy (SEM) images of the substrates after two-step lithography. (a) Bare glass. (b) Polymeric reservoir. (c) Silica nanoporous film. (d) Polymersilica nanocomposite coated glass. The scale bar is $100\\upmu\\mathrm{m}$ .  \n\n![](images/0d7905174b0704ba30b3e8a9c76a3db10c9cd7fbe63ac8a5fb066f3d0cbb457b.jpg)  \nFigure S7. Transmission spectra of the wet-style superhydrophobic antifogging coatings with respect to the micro-pillar interval to diameter ratio $(I/D)$ with a fixed micro-pillar diameter of $25\\upmu\\mathrm{m}$ .",
        "category": " Materials and methods"
    },
    {
        "id": 9,
        "chunk": "# WILEY-VCH  \n\n![](images/4019c428711fb45426f817c3b71bba5a4e6424a91b108ee26fb223fe5237cbd0.jpg)  \nFigure S8. Optical micrograph of the wet-style superhydrophobic antifogging coating before and after removal of the contaminant (sand, 40-100 mesh) via self-cleaning. The scale bar is $100\\upmu\\mathrm{m}$ .  \n\n![](images/17cc6e35cc6e3a542475f0f6ae020b6babd01ee95f7d93f81f9a10823ecd9ab5.jpg)  \nFigure S9. Transmission spectra of the various films under ambient condition (before) and in a fogging condition (after).",
        "category": " Results and discussion"
    },
    {
        "id": 10,
        "chunk": "# Supporting Movies  \n\nMovie S1. The application of the wet-style superhydrophobic antifogging coating on a curved surface.  \n\nMovie S2. Mechanical durability test of the wet-style superhydrophobic antifogging coating.  \n\nMovie S3. Water droplet repellency of the wet-style superhydrophobic antifogging coating under the fogging condition.",
        "category": " Results and discussion"
    }
]