[
    {
        "id": 1,
        "chunk": "# Article Long-Term Antifogging Coating Based on Black Phosphorus Hybrid Super-Hydrophilic Polymer Hetero-Network  \n\nLie ${\\mathbf{W}}{\\mathbf{u}}^{1,2}(\\mathbb{D}),$ , Yihong Kang 1, Yuhao Deng 1, Fan Yang 1,\\*, Rui He 1,\\* and Xue-Feng $\\Upsilon\\mathfrak{u}^{1,2,3,*\\oplus}$  \n\n1 Materials Interfaces Center, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China   \n2 University of Chinese Academy of Sciences, Beijing 100049, China   \n3 Hubei Three Gorges Laboratory, Yichang 443007, China   \n\\* Correspondence: fan.yang1@siat.ac.cn (F.Y.); rui.he1@siat.ac.cn (R.H.); xf.yu@siat.ac.cn (X.-F.Y.) Citation: Wu, L.; Kang, Y.; Deng, Y.; Yang, F.; He, R.; Yu, X.-F. Long-Term Antifogging Coating Based on Black Phosphorus Hybrid   \nSuper-Hydrophilic Polymer   \nHetero-Network. Nanomaterials 2023, 13, 86. https://doi.org/10.3390/ nano13010086  \n\nAcademic Editor: Sergei Kulinich  \n\nReceived: 26 November 2022   \nRevised: 20 December 2022   \nAccepted: 22 December 2022   \nPublished: 24 December 2022  \n\nCopyright: $\\circledcirc$ 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).  \n\nAbstract: The antifogging coating based on super-hydrophilic polymer is regarded as the most promising strategy to avoid fogging but suffers from short-term effectiveness due to antifogging failure induced by water invasion. In this study, a black phosphorus nanosheets (BPs) hybrid polymer hetero-network coating (PUA/PAHS/BPs HN) was prepared by UV curing for the first time to achieve long-term antifogging performance. The polymer hetero-network (HN) structure was composed of two novel cross-linked acrylic resin and polyurethane acrylate. Different from physical blending, a covalent P-C bond between BPs and polymer is generated by UV initiated free radical reaction, resulting in BPs firmly embedded in the polymer HN structure. The BPs enriched on the coating surface by UV regulating migration prevent permeation of water towards the inside of the coating through its own good water-based lubricity and water absorption capacity. Compared with the nonhybrid polymer HN, PUA/PAHS/BPs HN not only has higher hardness and better friction resistance properties, but also exhibits superior water resistance and longer antifogging duration. Since water invasion was greatly reduced by BPs, the PUA/PAHS/BPs HN coating maintained antifogging duration for $60~\\mathrm{{min}}$ under a $60~^{\\circ}C$ water vapor test and still maintained long-term antifogging performance after being immersed in water for 5 days.  \n\nKeywords: black phosphorus; hybrid; polymer; hetero-network; coating; long-term antifogging",
        "category": " Abstract"
    },
    {
        "id": 2,
        "chunk": "# 1. Introduction  \n\nWhen saturated water vapor condenses on a surface with a temperature lower than the dew point of the vapor, fog forms as tiny droplets that can scatter visible light [1–3]. For those transparent materials, surface fogging greatly reduces light transmittance, resulting in undesirable failure when applied in optical-related fields. For example, surface fog largely impacts the precision of optical and analytical instruments, such as infrared microscopes and clinical laparoscopy [4].  \n\nMany strategies, referring to super-hydrophobic and super-hydrophilic surfaces, have been developed for effective antifogging. Super-hydrophobic surfaces eliminate the effect of fog droplets by rolling down from the surface, but the light transmission tends to be compromised by the surface’s own micro/nano-structured roughness [4–7]. Different from super-hydrophobic surfaces, the antifogging coating based on super-hydrophilic polymer avoids fogging by quickly spreading fog droplets into a continuous water film, so as to effectively prevent the light scattering. Therefore, in the field of antifogging, superhydrophilic surfaces are easier, more reliable and more promising than super-hydrophobic surfaces [8–12]. However, as the water film on a super-hydrophilic surface grows to a certain thickness, polymer-based coatings suffer from loss of water-soluble components and swelling-induced peeling and cracking, which results in the antifogging failure of the coatings [13]. Therefore, polymer-based coatings are usually limited to short-term antifogging effectiveness due to their insufficient water resistance capability. To improve the water resistance of polymer-based coatings, some water-resistant organics such as hydrophobic components are usually added into the coatings. Unfortunately, these organics usually weaken the hydrophilicity of the coating, resulting in a decline in its antifogging ability. To date, it is still a huge challenge to balance the hydrophilicity and water resistance of polymer-based coatings [14].  \n\nGenerally, hydrophilic inorganic nanomaterials are able to absorb and store water without swelling, thus bringing a new strategy to regulate the balance between the hydrophilicity and water resistance of polymer-based coatings [15]. To improve the comprehensive properties of these organic–inorganic composites, more strategies for regulating compatibility, dispersion and stability of inorganic nanomaterials in the polymer-based coatings are required [16]. As a new hydrophilic two-dimensional inorganic nanomaterial [17,18], black phosphorus (BP) can improve the wear resistance and drainage capacity of the coating due to its excellent water-based lubrication performance [19–21]. On the other hand, BP possesses excellent compatibility with hydrophilic polymers, leading to universally good stability of the BP/polymer complex materials [22,23]. Unfortunately, the combination mode of BP with polymer reported at present is mostly weak physical blending rather than strong chemical combination [24–27], which greatly affects various performance attributes of BP-based polymer coatings. Therefore, although the BP-based polymer coating is a promising material for antifogging, some huge challenges, especially the chemical combination and microstructure regulation between BP and polymer, still need to be overcome.  \n\nIn this study, a long-term antifogging coating based on BP nanosheets (BPs) hybrid super-hydrophilic polymer hetero-network (HN) was designed and prepared by construction of P-C bond under UV curing. The polymer hetero-network (HN) structure [28,29] was composed of two novel cross-linked compounds, acrylic resin and polyurethane acrylate. Different from physical blending, a covalent P-C bond between BPs and polymer is generated by UV-initiated free radical reaction, resulting in BPs firmly embedded in the polymer HN structure. The BPs enriched on the coating surface by UV regulating migration can effectively prevent the permeation of water towards the inside of the coating through its own good water-based lubricity and water absorption capacity.",
        "category": " Introduction"
    },
    {
        "id": 3,
        "chunk": "# 2. Materials and Methods",
        "category": " Materials and methods"
    },
    {
        "id": 4,
        "chunk": "# 2.1. Materials  \n\nThe BP crystals were obtained from Mophos (www.Mophos.cn, Yichang, China). Polyethylene glycol 2000 (PEG 2000), 4-methoxyphenol (MeHQ, AR, $99.0\\%$ ), butylated hydroxytoluene (BHT), $>99.0\\%$ (GC)), dibutyltin dilaurate (DBTDL, $95\\%$ ), N-Methyl pyrrolidone (NMP), isophorone diisocyanate (IPDI, $99\\%$ ), pentaerythritol triacrylate (PETA, $96\\%$ ), ethyl acetate $(99.0\\%$ , GC), acrylic acid (AA, $>99.7\\%$ , GC), 2-hydroxyethyl methacrylate (HEMA, $99\\%$ ), sulfobetaine methacrylate (SBMA), azodiisobutyronitrile (AIBN, $99\\%$ ) and diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide (TPO, $97\\%$ ) were purchased from Aladdin Chemical Reagent Co., Ltd. (Shanghai China). All chemical regents were directly used without any further purification.",
        "category": " Materials and methods"
    },
    {
        "id": 5,
        "chunk": "# 2.2. Instruments  \n\nThe physicochemical properties of materials were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), optical microscopy, Raman scattering microscopy, $\\mathsf{X}$ -ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy and $^1\\mathrm{H}$ nuclear magnetic resonance spectroscopy $({}^{1}\\mathrm{HNMR})$ .  \n\nThe mechanical properties of coatings were characterized by mechanical instruments. The adhesion strength, hardness and friction resistance of coatings were measured on a direct pull tensile force machine, pencil hardness tester and ball disc friction tester, respectively.  \n\nThe hydrophilicity of coatings was measured by the water contact angle (WCA) tester, and the antifogging performance of the coatings was tested through a thermostatic water bath.",
        "category": " Materials and methods"
    },
    {
        "id": 6,
        "chunk": "# 2.3. Methods",
        "category": " Materials and methods"
    },
    {
        "id": 7,
        "chunk": "# 2.3.1. Preparation of Materials  \n\nSynthesis of polyurethane acrylate (PUA): $_{2\\mathrm{~g~}}$ PEG 2000, 6 mg MeHQ, $3\\mathrm{mg}$ BHT and $3\\mathrm{mg}$ DBTDL were dissolved in $20~\\mathrm{ml}$ ethyl acetate to obtain the dropping solution. A $444\\mathrm{mg}$ amount of IPDI was put into a three-port flask, and then the dropping solution was added to the three-port flask for $2\\mathrm{h}$ at room temperature under the stirring speed of $200\\mathrm{rpm}$ . The reaction was carried out at $40^{\\circ}C$ for $6\\mathrm{h},$ and then $500\\mathrm{mg}$ PETA was added to continue the reaction for $^{3\\mathrm{h}}$ at $80^{\\circ}C$ . After filtration and solvent evaporation, the residue was dried in a vacuum to yield a colorless oil.  \n\nSynthesis of P(AA-HEMA-SBMA) acrylic resin (PAHS): In a three-port flask, $3.6\\mathrm{g}$ AA, $6.5\\:\\mathrm{g}$ HEMA, $14\\mathrm{g}$ SBMA and $24\\mathrm{mg}$ AIBN were dissolved in $30\\mathrm{ml}$ ethyl acetate, and the reaction was carried out at $80~^{\\circ}C$ for $6\\mathrm{{h}}$ . After filtration and solvent evaporation, the residue was dried in a vacuum to yield a white powder.  \n\nSynthesis of black phosphorus nanosheets $(B P s)$ : The BPs were prepared by a liquid exfoliation method reported by our group. In brief, $10~\\mathrm{mg}$ of the bulk BP crystal was dispersed in $10~\\mathrm{mL}$ NMP and sonicated for $6\\mathrm{{h}}$ with an ultrasonic frequency of $19{-}25\\mathrm{kHz}$ (2 s ON and 4 s OFF; 1800 W; $6{}^{\\circ}\\mathrm{C}\\mathrm{\\cdot}$ ). The dispersion was centrifuged for $15\\mathrm{min}$ at $7000\\mathrm{rpm},$ and the collected supernatant was centrifuged for $15\\mathrm{min}$ at $12000\\mathrm{rpm}$ for further use.  \n\nSynthesis of super-hydrophilic polymer hetero-network coating $(P U A/P A H S H N)$ : The UVcurable solution was prepared by dissolving the photo initiator TPO and the obtained PUA, PAHS in 2-propanol with about $40\\%$ total solid content. The UV-curable solution was spin-coated on a plastic substrate, and then followed by UV irradiation (broadband, $400\\mathrm{mj}/\\mathrm{cm}^{2})$ to obtain a cured PUA/PAHS/BPs HN coating.  \n\nSynthesis of BPs hybrid super-hydrophilic polymer hetero-network coating (PUA/PAHS/BPs HN): The UV-curable solution was prepared by dissolving the photo initiator TPO and the obtained PUA, PAHS, BPs in 2-propanol with about $40\\%$ total solid content. The UV-curable solution was spin-coated on a plastic substrate, and then followed by UV irradiation (broadband, $400\\mathrm{\\mj/cm}^{2},$ ) to obtain a cured PUA/PAHS HN coating.",
        "category": " Materials and methods"
    },
    {
        "id": 8,
        "chunk": "# 2.3.2. Physicochemical Properties of Materials  \n\nCharacterization: SEM images were acquired from a Zeiss SUPRATM 55 SAPPHIRE (Oberkochen, Germany) field-emission scanning electron microscope. The SEM images were used to analyze the morphology of materials. The preparation method for samples was to take part of the UV- cured coating and paste it onto the sample table through conductive resin. The cross-section samples were pasted onto the cross-section sample table after freezing extraction. The AFM images were acquired from the Bruker Icon (Karlsruhe, Germany) atomic force microscope and were used to analyze the morphology of materials by detecting the atomic force between the sample and the probe. The samples were dispersed in EtOH and then dropped onto Si substrates for investigation. FTIR spectra were collected in a wavenumber range of $4000{\\mathrm{-}}400{\\mathrm{cm}}^{-1}$ on a Thermo Nicolet IS5 instrument (Waltham, MA, USA). The FTIR spectra were used to analyze the molecular structure of materials through functional group recognition. The preparation method for samples was KBr tableting. Raman scattering was conducted on a Horiba Jobin-Yvon Lab Ram HR VIS high-resolution confocal Raman microscope (Paris, France) equipped with a $633\\mathrm{nm}$ laser. The Raman FTIR spectra were used to analyze the structure of materials by Raman peak recognition. The samples were dispersed in EtOH and then dropped onto Si substrates for investigation. The $^1\\bar{\\mathrm{H}}$ NMR spectroscopy was performed on the Bruker Advance DRX-300 spectrometer (Karlsruhe, Germany) at $25^{\\circ}C$ and was used to analyze the structure of materials by NMR peak recognition. The samples were dissolved in deuterium reagent and then put into the nuclear magnetic tube. XPS spectra were obtained from a  \n\nThermo Escalab $250\\mathrm{{Xi}}$ spectrometer (Waltham, MA, USA) equipped with an $x$ -ray source producing Al $\\operatorname{K}\\alpha$ radiation $(1486.6\\mathrm{eV})$ . The XPS spectra were used to analyze the surface elements of materials. The samples were dispersed in EtOH and then dropped onto Si substrates for investigation.",
        "category": " Materials and methods"
    },
    {
        "id": 9,
        "chunk": "# 2.3.3. Performance Testing of Materials  \n\nMeasurement of mechanical properties of coatings: The adhesion strength of coatings was measured on a BGD500 direct pull tensile force machine by a pull-off test. The pull-off test was classified as a near to surface, partially destructive method that was able to measure the maximum tensile strength of the coatings. The hardness of the UV-cured coatings was measured by industrial pencil hardness tests (JIS K5400) on a QHQ-A pencil hardness tester. The tip of the pencil is placed on the coated substrate and scratched over the film. The hardness designation of the pencil that just fails to cut the film is the pencil hardness of the film. The lubrication performance of coatings was evaluated by coefficient of friction tests. The friction tests were completed using an MS-T3001 ball disc friction tester. A GG15 ball with a diameter of $6\\mathrm{mm}$ was a fixed friction, pair and the coating to be tested is a rotary disc.  \n\nThe friction coefficient was recorded in real time by the equipment system.  \n\nMeasurement of antifogging performance of coatings: The antifogging performance of coatings was evaluated by three methods. The first method was the hot water vapor test. The samples were held above a water bath containing $60^{\\circ}C$ water, and the distance between the samples and water surface was $5\\mathrm{cm}$ . The antifogging performance was measured by observing the fogging of coated substrates. The second method was to measure the hydrophilicity of coatings by testing the WCA. A $6~{\\upmu\\mathrm{L}}$ drop of water was placed onto the surface of the coating, and the WCA was analyzed by the image of water spreading. The third method was to investigate the light transmission over the $300{-}800\\mathrm{nm}$ wavelength range using a UV-Vis spectrophotometer during fogging tests.  \n\nMeasurement of antifogging cycle of coatings: The antifogging cycle tests were carried on a $60~^{\\circ}C$ water bath. The sample was first exposed to hot water vapor $(60~^{\\circ}\\mathrm{C})$ for $15\\mathrm{min}$ (denoted as the wet state). Then, the sample was dried at $40~^{\\circ}\\mathrm{C}$ for $^{4\\mathrm{h}}$ (denoted as the dry state). One cycle was completed, and the next cycle was carried out according to this method.  \n\nMeasurement of high and low temperature cycling resistance of coating: Placing the sample in a high and low temperature box, the program was set as follows: cool down to $-20^{\\circ}\\mathrm{C},$ keep the temperature at $-20^{\\circ}C$ for ${12\\mathrm{h}},$ and then raise the temperature to $80~^{\\circ}C,$ keep the temperature at $80~^{\\circ}C$ for ${12\\mathrm{h}},$ and the rate of temperature rise and fall is $1\\mathrm{{}^{\\circ}C/m i n}$ . One cycle was completed, and the next cycle was carried out according to this method. The antifogging performance of the coatings was evaluated after 10 cycles.",
        "category": " Materials and methods"
    },
    {
        "id": 10,
        "chunk": "# 3. Results and Discussion",
        "category": " Results and discussion"
    },
    {
        "id": 11,
        "chunk": "# 3.1. Material Synthesis and Characterization  \n\nThe polymer HN consisted of polyurethane acrylate (PUA) and acrylic resin (poly (acrylic acid (AA)-2-hydroxyethyl methacrylate (HEMA)-sulfobetaine methacrylate (SBMA), short for PAHS)), prepared by UV-initiated cross-linking. Both polymers have outstanding hydrophilicity and prominent adhesion on plastic substrates [11,30]. The UV-curable six functional PUA was prepared by polymerization of polyethylene glycol (PEG) with diisocyanate and end-capping with pentaerythritol triacrylate (PETA) (Supporting Information, Figure S1). PAHS was obtained by radical polymerization of three hydrophilic monomers AA, HEMA, SBMA, which contained generous hydrophilic groups (Figure S2). The $^1\\mathrm{H}$ nuclear magnetic resonance $\\cdot^{1}\\mathrm{HNMR})$ spectra and the Fourier transform infrared (FTIR) spectra of PUA and PAHS illustrated the successful synthesis of the two polymers (Figure S3–S5).  \n\nThe BP nanosheets (BPs) were obtained by a liquid exfoliation method reported by our group [31]. The scanning electron microscope (SEM) image (Figure S6) shows BPs about $200{-}300\\mathrm{nm}$ in size. The UV-curable solution prepared by dissolving the as-obtained PUA, PAHS, BPs and photootoiniintitaitaotroirnisnoslvolevnetnwt aws asspisnp-icno-actoeadteodn aonplasptilcastuicb sturabtset ranted iarnraddiirartaediatbeyd UbyV UtoV tsoynstyhnetshizeesiztehethBePBsPshyhbyrbirdidpoploylymerer HN coattiing (denoted  as PUA/PAHS//BBPsP s HN)N.).AsAshsohwonwin  iFnigFuirgeur1ea 1tah,ethyebhriydbirziadtizoant iofnBoPfs BanPsd tahnedctrhoessc-lrionsksliingkionfgPUofAPaUnAd PaAndHSPAocHcSuroreccdusrirmedu tsainmeuoltuaslnyeouunsdleyruUnVdierraUdiVatiiroran.diTahtieopn. tTohieniptihaottor ipnritoidatuocrepdrfordeuecreadifrcealesrtaodicnailtisattoeipniotliyatmeepriozlyatmioenrizoaftiaocrnyolfa taecrgyrloautepsgraonudpsgaenedrgateinoenr aotfioPnoCf bPo-nCdsb,otnhdus,etmhubsededminbge dBdPisnign tBhPespion ythme rpoHlyNmsterucHtuNres.tIrnucatdudriet. In oatdhdeitgioenetroa tiohen gofenPe-rCatbiondosf, tPh-eCibntoenrdacst,itohnesibnetterwaecetinoPn satboetmws eaendPhyatdorompshailnicdghryodurpospahlisloicegnrhoaunpcsesatlshoe estnahbailnitcyesotfhBePsst.abPilUitAy/PofABHPSs/.BPUs AH/NPAshHoSw/eBdPsnoHtNonslhyolwoendg-tneortmonsltyabliolintgy-tbeurtmalsstaobhiliigtyh bmuetcahlasonihciaglhstrmencghtahnidcuale  sttoretnhgetchrdosuselitnoktihnegcorfospsolilnykminergs.ofWpholeynmwerast.erWvhaepnorwcaotenrdveanspeodr con tdhensuerdfaocnetohfePsuUrAfa/cPeAoHf SP/UBPAs/PHANH, Sa/hBePmsi-HwNi,c kainhegmpih-ewnicokminegnopnheonccoumrerendononoctchuerrheydodnrotphheilhiycdrroupghiliscurfoaucgeh( Fsiugrufarcee1(bF)ig[3u2r]e. 1Tbh)e[3h2y].brTihdiezhatyibornidoifzaBtiPosninocfrBeaPseidnctrheaseudrftahce sruorufgachenreossu,gwhnhiecssh  mwahidcehthmeadweatehreswparteeardspmroeraedrmapoirdelryaopindtlhyeosnutrhfaecseurofatcheeocfotahteincgo,atihnugs, trheaulsizrienalgiztihnegetffhecteifvfecatinvteifaongtgiifnoggpienrgfopremrfaonrcmeaonfcPeUofAP/PUAH/SP/ABHPsS/HBNP.s HN.  \n\n![](images/a0fac85a11bc2673496e716195b4babf334aab305a87b842bfc6967257a2eb02.jpg)  \nFigure  1.  Schemattiic diiaagrraamofofdedseisgingnofoBfPBhPyhbyribdr ipdolpyolmyermeHrNHcNoactionagtifnogr feoffrecetffiveectaivnteifaongtigfionggpinergfpoerrmfoarnmcea.n(cae).S(ya)ntShyensitsheofs iPsUofAP/UPA/HPSA/BHPSs/BHPNs .H(bN) .A(nbt)ifAongtgiifnog gminecghamneicshma noifsPmUoAf/PUAAH/SP/ABHPsS/HBPNs.  \n\nThe SEM images of PUA/PAHS HN and PUA/PAHS/BPs HN are shown in Figure 2a,b, respeTcthiev eSlEy.MT hiemnaegtesworfkPsUtrAu/cPtuAreHfSorHmNe danbdy tPhUeAcr/oPsAs-HliSn/kBiPnsg oHfNPaUrAe sahnodwPnAiHnSFhigaudrae d2ia,bm, erteesrpeofctaivbeoluyt. $300{-}500\\mathrm{nm}$ ,k swtirtuhctmuircerofonr-smcealdebhyoltehedicaromsest-leirnakindgaobfoPutU $70\\%$ pdoProAsiHtyS. Thhaed amodriaphmoeltoegryofofatbhoeutne3t0w0–o5rk00stnrumc,tuwriethremiacirnoend-sbcalsiechalollyeudniachmaentgeredanwditahbtohueta7d0d%itiponrofosBitPys.. hTehemcoropshs-osleocgtyionf tShEeMneitmwaogrek sotfruPcUtuAre/PreAmHaSi/neBdPsbaHsiNcalilny FuingcuhraenSg7edshwoitwhs ihtse gaododidt ohnomofoBgePns.eiTthyeacnrdostsi-gsehct iconmSbEinMatiimonagewiotfhPtUheA/sPuAbsHtrSa/tBePs.s HTNhe nAFigMurdei aSg7rsahmowofs iPtsUgAo/oPdAhHoSm/oBgPesnHeitNysahnodwteigdhtthcatoBmPbsinwateiroenrewliathivtehley seuvebsntlryatdeis.trTibhueteAdFiMn tdhieagcroatminogf (Figure S8). The FTIR peaks of PUA at $3000{-}3100\\ \\mathrm{cm}^{-1}$ and $1650\\mathrm{cm}^{-1}$ were attributed t(oF gCu–rHe aS8n)d. ${\\mathrm{C}}{=}{\\mathrm{C}},$ TreIsRppecetaikvseloyf (PFiUgAuraets320c0a0–n3d10S09).cmC−1o amnpdar1e6d50wcitmh 1PwUeAr,etahtet $\\mathrm{{C-H}}$ adntdo $C{=}C$ peaks of PUA/PAHS/BPs HN disappeared, and some new peaks such as those at $10\\bar{3}9\\ \\mathrm{cm}^{-1}$ and $1240~\\mathrm{cm}^{-1}$ associated with the characteristic peak of PAHS and BPs, respectiv−1ely, appeared. 1This result shows that the free radical polymerization of $C{=}C$ and the hybridization of BPs were realized synchronously. High-resolution XPS (HR-XPS) spectra of PUA/PAHS/BPs HN were acquired and analyzed (Figures 2d,e and S10). As shown by the C 1s XPS spectrum, $\\mathrm{P-C},\\mathrm{C-O},$ and $C{=}0$ peaks at 284.1, 286.1, and $288.4\\mathrm{eV},$ respectively, confirmed the existence of P-C bonding and carbon oxygen covalent bonding of the polymers. The $\\mathrm{~P~}2\\mathrm{p}$ spectrum showed the $\\mathrm{P}2\\mathsf{p}_{3/2}$ and $\\mathrm{P}2\\mathrm{p}_{1/2}$ doublets at 129.6 and $130.5\\mathrm{eV},$ respectively, characteristic of crystalline BP. In addition, the broad peak at $133.3\\mathrm{eV}$ corresponded to P-C covalent bonds, corroborating chemical binding between BP aPnUdAPUbyAfbreyef reaedricaadlicraelarcetiaoctni.oCn.oCmopmarpeadrewditwhitPhUPAU/AP/APHAS HSNH,Nt ,htehReaRmaamnasnpsepcetrcturmumofof PUA/PAHS/BPss HNsshoowsst thhreree prroominineentntppeaeaksksofofBBPsP srerlealtaetdedtotoA $\\mathbf{A}_{\\mathrm{~g~}}^{1}$ a3t $361\\mathrm{{cm}^{-1}}$ ,g $\\mathsf{B}_{2\\mathrm{g}}$ a4t $438\\mathrm{cm}^{-1}$ danAd2 $\\mathrm{A}_{\\mathrm{~g~}}^{2}$ 4a6t $466\\thinspace\\mathrm{cm}^{-1}$ ,s presctpievcetliyve[l3y3[],33i]n,diincdaitcinatginpgrepsrersveartviaotnioonfoBfPBsPstsrturcutcutruere during hybridization (Figure 2f).. Thesserressultltss impllyyssuccceessfsuflulpprerepparartaitoinonofofthteh e HNN structure  and hybridization of BPs.  \n\n![](images/5b89d4e5bec727956e1df97ebc9ab6863434498404b1fcaf7ed315dcb99ba3db.jpg)  \nFigure  2.. Characterization  of BPs hybriid pollymeerr HNccooataitninggaannddnnoonnhyhbyrbirdidpoploylymemrerHHNNcocaotiantign.g. ((a)) SEMiimage of  PUA/PAHS HN..  ( b) SEM iimage offPUA//PPAHS/SB/PBsPsHHN.N(.c)(cF)TFITRIsRpsepctercatroafoPfAPHASH,S, PUA,,  PUA/PAHS HNaannddPPUA/AP/APHASH/BSP/sBPHsN.H(Nd.)  (Hd)R-HXRP-SXCPS1sCsp1escstrpuecmtroufmPUofA/PUAH/SP/BAPHsSH/BN.Ps (He)N.H(eR)-XHPRS-XPS2pP s2pescptreuctmruomf  oPfUPAU/PA/PHAS/HBSP/sBHPsN.H(Nf). (Rf)aRmamn asnpsecptercatroafoPf UPUA/AP/APHASHSHNHNanadnd PUA/PAHS/BPs HN.",
        "category": " Materials and methods"
    },
    {
        "id": 12,
        "chunk": "# 3..2. Mechanical pProperties offcCoaotaitningsgs  \n\nThe  mechanical  properties  of  PUA/PAHS  HN  and  PUA /PAHS/B/PBsPsHNNwererefufrutrhtehrer evalluated.. Compared with PUA/PAHS HN,, the  pencil  hardness  of  PUA/PAHS/B/PBsPs HNN iincreased from HB to 3H, which illustratestthatt BPsiimprroveedtthee haarrdnesessofofthtehecocaotaitnigng ((Fiigure 3a). Meanwhile, the WCA of PUA/PAHS//BBPsP s HNNdedcerceraesaesdedwiwtihththteh einicnrceraesaeseinin BPs contten t, iindiicattiing tthatttthe iinttrroducttiion offBPssiimprroveed ttheerorouugghhnnesessofofththeecocaotaitn-g. Tinhge siTmheulstiamneulotuasnieomupsroivmepmroevnetmofernotuogfhrnoeusgshaneds sharndnhesasrdthnreosusgthrBoPusghyBbPrisdhizyabtriiodnizwa-as btieonefiwcaisa lbteontehfiecisaclrtaotctheresscirsatacnhcre soifstahnecceoaftitnhge.cSoianticnega.dSihnecseioandshterseinogntshtroefntghtehcofathineg dceotaetrinmginedseitesrpmeienliensg irtesistpaeneclien,gpulrle-soifsftadnche,siopnusllt-roefnfgtahdtehsetsi onf PsUtrAe/nPgtAhHSt/esBtPss HofN aPnUdAP/UPA/HPS/ABHPSs HN oandpoPlyUeAt/hPylAenHeSteHreNpohtnhpaloaltye(tPhyElTe)n,eptoelryecparhbthoanlatte((PCE)T, )p, oploylmyceatrh-yl bmoenthataecr(yPlCa)t,ep(oPlMymMetAh)yalnmdetahcraycrloylnaiteri(leP-MbuMtaAd)ieaned- satcyryelnoeniterirlpe-oblyutmaedrie(nAe-BsSt)yrweneere epre-rfpoorlmyemde.rA(lAl sBuS)bswtrearte spewrefroer tmraend.spAalrlesnutbasntrdatsemsowotehreptlratensp(sairzen $50\\mathrm{mm}\\times50\\mathrm{mm},$ tehsic(ksinzess $3\\mathrm{mm}^{\\cdot}$ )m,  a×n5d0thmemt,hitchkicnkenssesosf3thme cmo),ataingdstohbettahiincekdneosnstohfetdhieffceoreatnitnsgusbostbrtatiensedwaosn $50~{\\upmu\\mathrm{m}}$ f-by df erfeanutlts.uAbstrsahtoeswnw aisn  5F0igμumreb3yb,dtehfaeualtd.hAesisohnoswtrneingtFhigoufrPeU3bA,/thPeAaHdSheHsiNonwstarsebnegthweoefn $1.7{-}3.5\\mathrm{MPa}$ ,HillNuswtraastibnetgwteheant t1.o7p–o3l.o5gMicPala eilnltuasntrgalteinmgetnht atntodpcolvoagliecanltebnotanndgilnegmweinthasnudbsctoravtaelsenotfbponlydimnegrwHitNh smuabdstertahtescofatpionlgyfimremr lHyNadmhaerde otnhedcifofaetriengt fpirlamsltiycasduhbesrteraotnesd[i2f-8]. Tfehre nitntprloadstuictisounbsotrfatBePss f2u8]r.thTehreeinthraondcuecdt tohneoafdBhPesifounr hoefrtheenhcaonactiendgt,hienadidchaetisinogntohfat hthyeb rciodaitziantigo,ninodficBaPtsinigmtphraotvhesytbhriedtiozaptoilongiocfalBePnstiamngplreomvesn thbettwoepeolnopgioclaylmeenrtsa.nTghlemcoeenftficbietnwt eoefnfrpicotliyomne(rCs.OTFh)econetfifnicuiendttof fdreictlionne (wCitOhF)thceonitnicnrueeadsetoindeBcPlisnceowntitehnt.heCioncmrpearsed iwnitBhPtshceonHteNntc.oCatoinmgpawrietdhowuithBtPhse, tHhNe cCoOatFinogf wPiUthAo/uPtABPHsS, t/hBePsCOHFNofdPecUreAa/sPeAdHbSy/ $68\\%$ , inHdNicdateicnrgeatsheadt sbuycc6e8ss%f,uilnhdyicbartiidnigzathioatnsoufcBcePssfgurelahtlybirimdipzraotvieodn tohfeBlPusbrgircietaytloyfitmheprcovateidng (Figure 3c). Benefiting from the lubrication of BPs, the WCA of PUA/PAHS/BPs HN did not rise significantly after 1000 friction test cycles, showing its excellent friction resistance property (Figure 3d). These results indicate that the hybridization of BPs can effectively improve the hardness, roughness, adhesion strength and friction resistance of polymer HN.  \n\n![](images/a656091653c1a971bff54c6dfdf54892c77eb8a3e01c03ecab7074bcad947428.jpg)  \nFigure  3. Mechanical properties of BPs hybrid polymer HN coating and nonhybrid polymer HN coating. (a) Pencil hardness offPUA/PAHS/BPs HN with different BPs conttentt. Inset: WCA of PUA/PAHS/BBPPss HN witihthdidfiffefrernetntBPBsPscocnotnetnet.nt(.b()bA)dAhdeshieosniosntrsetnregtnhgtohf oPfUPAU/PA/HPAS/HBSPs/ BHPNs  aHnNd and PUA/PAHS on PET, PC, PMMA and PBS substrates. (c) Coefficient of friction (COF) curve of PUA/PAHS/BPs HN with different BPs content. Inset: schematic diagram of ball disc friction tests. (d) WCA of the PUA/PAHS/BPs HN and PUA/PAHS HN under different friction cycle tests.",
        "category": " Results and discussion"
    },
    {
        "id": 13,
        "chunk": "# 3.3 Antifogging Pperformances of cCoattiings  \n\nWhen  BPs conttentt offtthe HN coattiing wasslleessstthaan $6\\mathrm{wt\\%}$ %, ,PPUA//PAHS/BPs HN  had a lliight ttransmittance higher than $90\\%$ ((Fiigure S11)). Considering the transmittance and mechanical properties of the coating, we chose to add $6\\mathrm{wt\\%}$ BPs into the HN coating thereafter. The susttaiined anttiiffoggiing peerrfforrmaancceeooff PUA/ PAHS/BPs HN was evaluated by  the $60^{\\circ}C$ hot water vapor test for $60\\mathrm{min}$ . Compared with bare PMMA slide, the PMMA slide coated with PUA/PAHSS/B/PBsPsHHNNprpersesnetnetdeadsauspuepr-ehr-yhdyrodrpohpilhicilsitcasttea(teW $(\\mathrm{W}{\\bf C}\\mathbf{A}=8^{\\circ}$ ) ahnad haalidghatlitrgahntstrmaitntsamncitet ahnigcehehritghaenr t9h0a%n $90\\%$ tohvee3r0t0h–e8 $300{-}800~\\mathrm{nm}$ ewnagvtehleranngtghe ruandger u60ndmeir $60\\mathrm{min}$ cuonutsinaunotiufsogagnitinfgogtegsitn(gFtiegsutr(eFi4ga)u.reTh4ea)o.pTtihcealopthicoatlogprhaoptohgsrianpFhisgiunr eFi4gbusrheo4wb sthaotwthtehactotahtedc oPatMeMd APMsliMdeAdsilidneodtifdognowt fhoegn ewxhpeonsedxptosheodt two ahtoetr vwapteor  v(6a0po°rC $(60~^{\\circ}\\mathrm{C})$ fmori $60~\\mathrm{{min}}$ , twhehiblearteheP bMaMreAPsMlidMeAfosgligdedfeovgegne idnetvhenfirns thme nfiurstte.mTihneuste. Tsuhletse nredsicualtse itnhdaitctahte tBhPasththyeb rBidPspholybrmiedrpHolNy cmoeartiHngNpcosasteisnsgespossusetasisnesedsuasnttaiifnoegdgiangtiafboigligtiyn.gInabaidlidtiy-. Itinoand, dPitUioAn/,PPAUHAS/BPAsHS/NBoPns PHMNMonAPslMidMesArselimdaeisnredmhaiignheldyhtirgahnlsyptaraenstp(aorpetnicta(lotprtaicnasltrmaitntsamncitetaonvceer 9o0v%er) $90\\%$ )ngdsuerivnegn sweevte–ndrwyecty–cdlreys ocfyaclnetsi ofggaintgiftoegstgsi,nigl tuessttrsa, inllguistsrlaotingitesr lmonagn-dtesrtmablaenadntsitfaobglge nagntipfeorgfogrinmganpcer f(oFrigmuarnec4ec)(.FiTgoufruer $\\mathsf{4c}\\mathbf{\\bar{\\Psi}}$ )e.r Tnoalfyuzrethtehre ainfalluyeznecethoef iBnPflsueoncetohfeBPasn toifnotghgeinagn tipfoergfgoirnmg apnecrfeoromf atnhce  ocfotahtiencgo,atsiunsgt,asinuestdainaentdi faongtigfiong itnegstsestosf oPfUPAU/PAA/PHASHSNHaNndanPdUPAU/PA/PHAS/HBSP/sBHPsNHwNithwidtihffedrifefnetrethnitctkhnicesksnessweesrewecroencdounctdeudc.teAds. tAhsethinecirnecarseasien  icnocaotiantigngthtihcikcnkensesscocouludld delelaayy watter invasion,,  thicker PUA/PAHS HN yielded antifogging performance for a longer duration (Figure 4d). Unfortunately, it was still difficult to maintain $60\\mathrm{min}$ antifogging duration with the PUA/PAHS HN even with increased thickness. In contrast to the PUA/PAHS HN, the PUA/PAHS/BPs HNs with $5\\upmu\\mathrm{m},20\\upmu\\mathrm{m}$ and $50~{\\upmu\\mathrm{m}}$ thicknesses were able to maintain over $90\\%$ light transmittance when exposed to hot water vapor $(60^{\\circ}\\mathrm{C})$ for $60\\mathrm{min}$ . The optical photographs in Figure 4e s4heoswhtohwat haant iafontgifgoinggipnegrfpoer fmoarnmcaenocfePofUPAU/AP/APHAS HSNHdNedcleicnliendeadftaefrtebrebineignigmimemresresdeidn winatewraftoer f1odra1y,dany,dacnodmcpolemtepllye tfealiylefda ialfetderaf5tedra5ysd. aHyso.wHeovewr,etvheer,PthUeAP/UPA/HPSA/HBSP/sBHPsNHstNill mstaiillntmaianinetdailnoendg -ltoenrgm-taerntmifoagntgiifnoggaibniglitaybielivteyneavfetenrabfteirngb eiimngmiermsemderisnedwianterwfaotrer5fdora y5s. Tdhaeysse. rTehseusletsredseulmtso ndsetrmaotenstthrae eo uthtsetaonutdsitnagndwinatgerwraetesirsrteasnicsteaancnedalnodngl-otnegr-mteramntiafnotgifgoign-g pgeirnfgormpaenrfcoeromfaPncUeA/oPfAHPSU/AB/PsAHSN/.BTPos fuHrtNh.er sTtoudfyutrhtehesrt absitliutdyyof tPhUe As/tPabAilHitSy/BoPfs HPNU,Ai/tsPAhyHdSr/oBpPsh ilHicNit,yitswhaysdtreostpehdi iacfiteyrwloasngte-tseterdmaeftxeprolsounrge-tteormhuexmpiodsuaire. ToheumWiCdAa ro.f PTUhAe /WPCAAHSo/f BPUsAH/PNAoHnS/dBifPfserHenNt sounbdsitfrfaetresntdisdubnsottrartiesse  sdigdnifiotcarinstelysiagftneifriceaxnptloysuarfetetro aeirxpforsu6rewteoeakisr (fFoirg6urwe e4efk),s (wFhiigluerteh4e ),WwChAi eofthPeUWAC/PAAoHf SPUHAN/PrAosHeSsiHgnNi fircoasentsliygnaifftie-r ecxapnotlsyuraeftteor aeixrpfosrur1ewtoe eakir. Ionr a1dwdieteiko.nI,nPaUdAdi/tiPoAn,HPSU/BA/PsAHNS/hBaPds bHeNtt ehrahdibgehttaenrdhilgohw teanmdpleorawttuerempceyrcalitnurgerceyscilsitnagncrestishtancPe tUhAa/nPAUHAS/PHANHS( FHigNu(rFe gSu1r2e),Ss1u2)g,gseusgtignesg tnhgathtahte htyhberihdyibzraitdiioznatoifonBPosf eBnPhsaencheadntcheed thertmhearlmstalbsitliatbyiloitfyHofN.HTNh.eTseherses rueltsuilltlsuislltruasterattheathtahte BtPhsehByPbsrihdybproildypmoelryHmeNrcHoaNticnogathiansgehxacselelexncte llweanterw-raetseirs-traenstisatanndt antidf oagntgifnoggpienrgfopremrfaonrc-e anmdanocuetsatnadndoiuntgstsatnadbilnitgy,s tahbuilsitayc,htiheuvsinagchitisevliong-itserlomnag-nteifromggaintigfocgagpianbgilictayp.  \n\n![](images/cf779cc0d3fe4fbe0dd30d9fb1309a8f41ae52022433379804bc43f416b1b64d.jpg)  \nFFiiggurree4.4.Anttiiffoggiing  performances of BPs hybrid polymer HN coattiing and nonhybrriid pollymeerr HN ccooataiting.g.((a))The averrage ttrransmiitttance offPUA/PAHS/BPss HN--ccoaatteed PMMAaanddbbaraere PMMA (t(rtarannsspparaerentntaannddssmootohthplpaltaetse,s,siszize $75\\times25\\:\\mathrm{mm}.$ ,tthicickneesss $3\\mathrm{mm}$ ) wheenneexxpoosseeddttoo hoot t wataetrervvaapoorr $(60\\ ^{\\circ}\\mathrm{C})$ for $60\\mathrm{min}$ . Inset: WCA of PUA/PAHS/BPs HN-coated PMMA $(8^{\\circ})$ and bare PMMA $(73^{\\circ})$ . (b) Optical photographs of a bare PMMA slide and a PMMA slide coated with PUA/PAHS/BPs HN when exposed to hot water vapor $(60~^{\\circ}C)$ for $1\\mathrm{min}$ and $60~\\mathrm{{min}}$ . (c) The average transmittagnracephosfoaf tPhMe PMAMslAidsel dcoeastheodwwai tghooPdUfAie/ldPAofHvSis/ioBnPdsuHrinNgdaunrtifnog gciyncglicteastntaiftoerg gsienvgentewstest. Trhye ocpytcilceasl p(hdo)toTghraephasveorfatghee tPraMnsMmAittsalindce  shofowPaMgMoAod sfiliedledsofcovaistieodn dwuitrhingPUanAt/ifPoAgHgiSngHteNst afntder sePvUeAn/PwAetH–dS/rByPcsycHleNs,. r(eds)pTechteivaevleyr,awgiethtrvaanrsyminitgtathnicekonfesPsMwMheAnselixdpeos ecdoattoehdotwiwthatPerUvAa/pPorA(H60S°HC)N aonvderPtUimAe/.P(Ae)HASn/tiBfPosg gHinNg,  breshpaevcitoirvoelfy,PMwitMhAvsalriydiensg( trhaincskpnaersesntwahnedn semxpootshedpltaotehso,tsiwzeat5e0r vmamp×or $(60\\ ^{\\circ}\\mathrm{C})$ ,otvheircktinmeses. 3(em) mA)ntciofaotgegdi nwgitbhePhUavAi/oPrAofHPSMHMNAansdliPdeUsA(/trPaAnHspS/a6rewnt%anBdPsmHoNo,trhespleactteisv,esliyz,e $50\\mathrm{mm}\\times50\\mathrm{mm}$ , thickness $3\\mathrm{mm}$ ) coated with PUA/PAHS HN and PUA/PAHS/ $6\\mathrm{wt\\%}$ BPs HN, respectively, after being immersed in water for different periods of time. (f) WCA of PUA/PAHS/BPs HN on PET, PC, PMMA and PBS substrates after exposure to air for 1, 2, 3, 4, 5 and 6 weeks, respectively.",
        "category": " Results and discussion"
    },
    {
        "id": 14,
        "chunk": "# 3.4. Long-Term Antifogging Mechanism of Coatings  \n\nBased on these results, the long-term antifogging mechanism of PUA/PAHS/BPs HN is proposed in Figure 5a. Due to the different surface tensions of BPs and organic polymers, solvent evaporation drives Bénard Marangoni convection during the process of  \n\nUsuVrfcaucreinmga[k3e4]i.t BdiPfsfitceunltdftor  mwiagtreartteotopewnaertdrsattehteocwoartidnsgthseurifnasciededuofe thoeBcéonatirndg,Mpareavnegnot-ni ciongvaenctifong,girnesguflatilnugreiin tdhuecegdenbeyrawtiatoenr ionfvamsiicorno.stTroucvteurirfeyathnids aisnscuremaspetidonr,ouWgChAnetses so,n thmeicsruorsfcaocpei. oDbuse rtvoaetixocnesllaentdwatter-bpaesnedtrlautibornictiteystsanofd PwUatAe/rPaAbHsSo/rBptPisonHcNapwaecrietyc,oBnP-s odnutchteds.uWrfiatchethmeaiknecrietadseififincuUltVfcourriwnagtteirmteo, tpheeneWtrCatAe otfotwhaerdHsNthcoeaitninsigddeeocfretahse cdofartoinmg, p2r3e°vteon t8in°,gianndtiicfaotgingignignfcarielausredinrdoucgehdnebsyswofa tehreincovatsinogns. TdourvienrgifyUtVh icsuarsisnugm(Fpitigounr,eW5bC).A teOsptst,icmalicmriocsrcospciocpoicbsoebrsveartviaotniosnaonfdthweacteora tpinegnesturraftaicoen(taebstosutof1PμUmAt/hiPcAk)HbSe/fBorPesaHndNafwtere cUonVdcucrtiendg. wWaisthfutrhteheirncroenadseucitnedU.VThceurminicgrtoismcoe,pitchephWotCogAraopf hthseofHPNUcAo/aPtiAnHgSd/BecPrseaHsNed firnomF $23^{\\circ}$ eto5 $8^{\\circ}$ s,hinodwictahtiant gBiPnscrmeiagsreadterodutgohwnaersdssotfhtehecocaotaitninggsudrfuarciengduUriVncgurUinVgc(uFriignugr,er5eb-). Osuplttiicnagl imnicernorsicohpmicenotbosferBvPastion tohfethseurcfoactei.nTghseusrefarcesu(altbsopurt $1\\upmu\\mathrm{m}$ atthiBcék)n abredforMeaaranndgaofnteir UcoVncvuercitniognwoafsBfuPrstahnerdcponldyumcetresd.ocTchuerrmeidc rionstchoipsisctupdhyo.toTghreaipmhsprofo vPeUmAe/ntPAofHhSy/dBrPosphHilNici-n Fiitgyuisreat5tcrisbhuotewdtthoathBePinscmreiagsreatiendctoatwinargdrsotuhgehcnoeastsi nafgtesruerfnarcicehdmuerintgofUBVPsc uorni tnhge, rseusrufaltcien.g inToe fnurircthemreantaolfyzBePtshoenwtahtersurerfsaisctea.nTcheeosfePreUsAu/ltPsApHroSv/eBPthsaHt BNé,nitasrdwaMtear apnergmoneiacboilnitvyecwtiaosn otfesBtPesdanafdteprolybeminergs oicmcumrerresdeidn tihnis swtautdery. fTohre i5mpdraoyvs.emTehnet ofwhatyedrropehnileitcriattyioisnatrtaritbeutoefd tPoUthAe/PinAcrHeSa/sBePisnHcoNatdinecgreraosuegdhnweitshs atfhteradendirtiicohnmoefntBPosf cBoPnsteont tahnedsuprfoamceo. oTon foufrther amnalsyszreatihoeofwaPtUerArteosisPtAanHcSe(oFfigPuUreA5/dP).ATHhSe/cBrPosslHinNk,iintgs dweantseirtypeorfmpoelaybimlietrys iwnacsretaesetedd afwtietrhbtehiengadi dmitmioernseofd iPnUwAactoerntfeonrt,5 rdeasyusl.t Tngheinwatdere npsenretHraNtisotnrurcatueroefaPnUdAlo/wPAerHwS/atBePrs HpeNnedtercartieoanserdatew.iItnh  athdediatidodni,titohen ionftrBoPdsucotinotne notf aBnPds cpornotrmiobtuitoendotfotbhleo cmkiansgs trhateiopeorfmPeUa-A ttoioPnAoHf Sw(aFtiegr,utrheu5sde)n. hTahnec cnrgostshleinwkaitnegr rdesnistitayncoefopfoPlyUmAe/rPsAiHncSr/eBaPsedHNwiitnhatheuamdiditeino-n ovfirPoUnAmecnotn.tent, resulting in a denser HN structure and lower water penetration rate. In additiTohne, athbeovien trreosdulutcstidoenmofnsBtPrastceothnterliobnugt-etdertmo balnoticfkoigngintghepeprefrormeatnicoenmofecwhatneirs,mthoufs etnhheapnrcoipnogstehdecwoatienrgr.esistance of PUA/PAHS/BPs HN in a humid environment.  \n\n![](images/a4d497e4073a54918d80903b24e881eea1c4d10b87b5c149ab4ea3ff109fdb78.jpg)  \nFiigurre 5. (a) Schematiticc diaiaggraramofoflolnogn-gte-tremrmanatinftoifgogigngginmg emcheacnhiasnmisomf PofUPA/UPA/HPSA/BHPSs/HBPNs. (Hb)N. (b) WCA of PUA/PAHS/BPs HN with different UV curing times. (c) Microscopic photographs of PUA/PAHS/BPs HN before and after UV curing. (d) Water penetration rate of PUA/PAHS/BPs HN with different BPs content and mass ratio of PUA to PAHS.  \n\nThe above results demonstrate the long-term antifogging performance mechanism of the proposed coating.",
        "category": " Results and discussion"
    },
    {
        "id": 15,
        "chunk": "# 4. Conclusions  \n\nIn summary, for the first time, a BPs hybrid super-hydrophilic polymer HN coating (PUA/PAHS/BPs HN) was prepared by UV curing for long-term antifogging performance. Different from physical blending, covalent P-C bonds between BPs and polymer were generated by UV-initiated free radical reaction, resulting in BPs firmly embedded in the polymer HN structure. The BPs enriched on the coating surface by UV regulating migration can effectively prevent the permeation of water towards the inside of the coating through its own good water-based lubricity and water absorption capacity. Compared with nonhybrid polymer HN, PUA/PAHS/BPs HN not only has higher hardness and better friction resistance properties, but also exhibits superior water resistance and longer antifogging duration. Since water invasion is greatly reduced by BPs, PUA/PAHS/BPs HN maintained 60 min antifogging duration under the $60~^{\\circ}C$ water vapor test and still maintained long-term antifogging performance after being immersed in water for 5 days. After exposure to air for 6 weeks, the antifogging performance of PUA/PAHS/BPs HN did not decline, showing its outstanding stability. This study provides not only a method for fabricating BP hybrid polymer materials through the generation of P–C bonds induced by free radical reaction, but also a new way for regulating the directional enrichment of BP towards the surface of a composite structure, which presents new approaches for long-term antifogging in humid environments.  \n\nSupplementary Materials: The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/nano13010086/s1, instruments; Figures S1 and S2: Schematic diagram of synthesis of PUA and PAHS; Figures S3 and S4: 1 H NMR spectra of PUA and PAHS; Figure S5: FTIR spectrum of (a) PUA; (b) PAHS; Figure S6: SEM image of BPs; Figure S7: Crosssectional SEM image of PUA/PAHS/BPs HN; Figure S8: AFM image of PUA/PAHS/BPs HN; Figure S9: FTIR spectrum of (a) PUA/PAHS HN; (b) PUA/PAHS/BPs HN; Figure S10: XPS spectrum of PUA/PAHS/BPs HN; Figure S11: Transmission spectra of PUA/PAHS/BPs HN with (a) $0{-}6~\\mathrm{wt\\%}$ BPs; (b) $8–18\\mathrm{wt\\%}$ BPs; Figure S12: Transmission spectra of PUA/PAHS/BPs HN during high and low temperature cycles.  \n\nAuthor Contributions: Project administration, X.-F.Y., R.H. and F.Y.; conceptualization, X.-F.Y., R.H., F.Y. and L.W.; funding acquisition, X.-F.Y., R.H. and F.Y.; investigation, L.W., Y.K. and Y.D.; methodology, L.W.; visualization, L.W.; writing—original draft, L.W.; writing—review and editing, X.-F.Y., R.H., F.Y. and L.W. All authors have read and agreed to the published version of the manuscript.  \n\nFunding: This study was supported by Guangdong Basic and Applied Basic Research Foundation (2020B1515120040); Shenzhen Basic Research Foundation (JCYJ20200109115408041); Guangdong Basic and Applied Basic Research Foundation (2020A1515110831); Shenzhen Science and Technology Program (Grant No. RCJC20200714114435061).  \n\nData Availability Statement: The data presented in this study are available on request from the corresponding author.  \n\nConflicts of Interest: The authors declare no conflict of interest.",
        "category": " Conclusions"
    },
    {
        "id": 16,
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        "category": " References"
    }
]