[
    {
        "id": 1,
        "chunk": "# Anti-fogging properties of amphiphilic copolymer films deposited by chemical vapor deposition (CVD)  \n\nMelek Dinç Tuna a, Emine Sevgili Mercan b, Mehmet Gürsoy b,c, Mustafa Karaman b,c,\\*  \n\na Mechanical and Chemical Industry Inc., Ankara 06560, Turkey   \nb Department of Chemical Engineering, Konya Technical University, Konya 42030, Turkey   \nc Nanotechnology and Advanced Materials Development Application and Research Center, Konya Technical University, Konya 42030, Turkey",
        "category": " Abstract"
    },
    {
        "id": 2,
        "chunk": "# A R T I C L E  I N F O",
        "category": " Abstract"
    },
    {
        "id": 3,
        "chunk": "# A B S T R A C T  \n\nKeywords: Anti-fogging Amphiphilic Copolymer Thin film CVD  \n\nThis study demonstrates the deposition of an amphiphilic copolymer as an anti-fogging coating on the glass and mirror surfaces. For this purpose, copolymer films of 2,2,2,3,4,4,4,4 hexafluorobutyl acrylate (HFBA) with 2- (dimethylamino)ethyl methacrylate (DMAEMA) were synthesized using initiated chemical vapor deposition (iCVD). During the iCVD process by adjusting the flow rate ratio of the monomers, the amount of fluorinated moiety in the P(HFBA-DMAEMA) was systematically tuned, which was confirmed through FTIR and XPS ana­ lyses. According to the water contact angle measurements, coatings were shown to be more hydrophobic with increasing fraction of fluorine atoms in their structures. The P(HFBA-DMAEMA)-deposited surfaces showed outstanding and long-lasting anti-fogging performance while maintaining high optical transmissivity. Films were observed to be functional in terms of anti-fogging behavior even after 1-year from the initial coating process, which confirms the durability of the films.",
        "category": " Abstract"
    },
    {
        "id": 4,
        "chunk": "# 1. Introduction  \n\nGlasses and mirrors, widely used in a wide range of applications, are essential materials for everyday life. In the future, smart devices using glass and mirror are expected to become more widespread in both in­ dividual and industrial level. When the temperature of the surrounding air is equal to or lower than the dew point, fogging occurs on the surface of the materials. Water droplets accumulated on the surface cause the refraction and reflection of light [1]. This not only reduces the trans­ parency of glass and mirror, but also adversely affects the efficiency of the devices in which they are used. Therefore, it is very important to prevent surface fogging. Various strategies have been developed for this purpose. Changing ambient conditions (e.g. relative humidity and air flow), heating, and wiping material surfaces are among the most tradi­ tional strategies to prevent fogging [2]. These strategies often require infrastructure and complex equipment to be implemented effectively. Another anti-fogging strategy is coating material surfaces to change their wetting properties. It is possible to prevent fogging by transforming surfaces into hydrophobic or hydrophilic coatings. The purpose of the hydrophobic coating is to minimize the contact area of the fog droplets with the surface and to ensure that the droplets roll away from the surface [3]. In most cases, for this to be successful, the droplets need to reach a certain weight and/or the materials need to be inclined [4,5]. Moreover, hydrophobic coatings are not always sufficient for the sepa­ ration of water droplets from the surface, so superhydrophobic coatings are mostly needed [6,7]. Generally, superhydrophobic coatings contain nano- and micro-sized roughness’s, which may limit their use in some application areas. The purpose of hydrophilic coatings is to allow the fog to spread on the surface as a thin film instead of droplets. In this way, drop-sourced light scattering is prevented [8]. However, when the amount of condensation on the surface exceeds the capacity of the film, the overflowing water layer can cause various problems. They are also susceptible to organic pollutant contamination due to their high surface energy [9]. Neither hydrophilic nor hydrophobic coatings can perform excellent anti-fogging performance in all conditions due to the afore­ mentioned handicaps.  \n\nThe coatings having hydrophilic and hydrophobic properties at the same time are expected to exhibit effective fogging performance. While the hydrophilic parts allow water to spread on the surface, the hydro­ phobic parts prevent the coating from dissolving. Therefore, there has been a growing interest in the production of amphiphilic coatings to be used for anti-fogging purposes in recent years [10–13]. The techniques used to produce amphiphilic coatings can be classified under two main groups: wet and dry techniques. Atom transfer radical polymerization (ATRP), electrospinning, sol-gel, and reversible addition–fragmentation chain-transfer (RAFT) can be given as examples of wet techniques [14–17]. These techniques require time-consuming extra steps such as purification, heating, and washing. In addition, the use of aggressive and toxic solutions poses a threat to both living organisms and the envi­ ronment. Dry techniques eliminate the problems encountered in using wet techniques such as the consumption of toxic solutions and excess chemicals. The environmentally friendly initiated chemical vapor deposition (iCVD) process, as a dry technique, is a versatile technique in polymer production [18]. In iCVD process, monomers are not dissolved in any solution as in wet techniques, their vapors are fed directly into the reactor. Therefore, iCVD process eliminates the solvent related prob­ lems, including surface-tension-driven instability, microphase separa­ tion, post purification steps, and solvent disposal costs [19,20]. All these unique advantages make the iCVD process an ideal technique for the production of amphiphilic polymers. However, there are very few studies on the production of amphiphilic polymers using iCVD. In these studies, antifouling and antibiofouling performances of the films have been investigated [21–24]. In this study, for the first time, amphiphilic polymeric thin films were produced by copolymerization of 2,2,2,3,4,4, 4,4 hexafluorobutyl acrylate (HFBA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) monomers using iCVD technique. Copolymer films with different chemical compositions were produced by changing the flow rate ratios of the monomers. The anti-fogging properties of copolymer films coated on glass and mirror were investigated.",
        "category": " Introduction"
    },
    {
        "id": 5,
        "chunk": "# 2. Materials and methods",
        "category": " Materials and methods"
    },
    {
        "id": 6,
        "chunk": "# 2.1. Materials  \n\nThe monomers HFBA $(95~\\%)$ ), DMAEMA $(98~\\%)$ and the initiator di‑tert butyl peroxide (TBPO, $98\\%$ ) were acquired from Sigma–Aldrich. The precursors were utilized as received without any additional modi­ fication or post-purification procedures. Glass slide (ISOLABLaborgera¨te GmbH), mirror and silicon wafer (100, p-type) were used as substrates.",
        "category": " Materials and methods"
    },
    {
        "id": 7,
        "chunk": "# 2.2. iCVD of amphiphilic film  \n\nThe iCVD process for amphiphilic film coatings was conducted within a specially constructed stainless-steel chamber measuring $20\\mathrm{cm}$ in width, $30\\mathrm{cm}$ in length, and $5\\mathrm{cm}$ in height. The schematic drawing of the iCVD system used is given in Fig. 1a and a more detailed description of the system used in this study was given elsewhere [25]. The reaction scheme of HFBA and DMAEMA in iCVD in the presence of TBPO initiator is shown in Fig. 1b.  \n\nThe substrates were kept at a constant temperature during polymerization by placing them on the reactor floor with a heat exchanger on the backside, which was connected to a recirculating chiller (Thermo Neslab). The energy required for the polymerization was provided by a tungsten filament array (Alfa-Aesar, $99.95\\:\\%$ ) placed $22~\\mathrm{mm}$ above the reactor floor. The resistive heating of tungsten fila­ ment was achieved by using a variac. The temperature of the filament array was continuously monitored using a K type thermocouple (Omega) in contact with it. According to the temperature reading, the current passing through the filament was manually adjusted by variac to reach the desired filament temperature. The precursors were placed in individual stainless-steel jars and their vapors were fed in the reactor using needle valves (Swagelock). The temperatures of DMAEMA, HFBA and TBPO were kept constant at $55^{\\circ}\\mathrm{C},$ , $25~^{\\circ}\\mathrm{C}$ and $25^{\\circ}\\mathrm{C}_{:}$ , respectively, using a proportional-integral-derivative (PID) controlled heaters. Vac­ uum environment was created inside the reactor by a rotary vacuum pump (Edwards RV8). The pressure within the reactor was monitored using a capacitance-type manometer (MKS). To maintain the pressure at the desired level, a PID-controlled butterfly valve (MKS) was placed between the vacuum pump and the reactor. By adjusting the flow rate ratios of HFBA/DMAEMA, it was aimed to fabricate amphiphilic poly­ mers with different chemical compositions. The amphiphilic polymers were deposited using three different DMAEMA flow rates, while the flow rates of both TBPO and HFBA were kept constant at 1.0 sccm. Thin films were named as follows: AP1, AP2 and AP3. AP1, AP2 and AP3; which were produced with HFBA/DMAEMA flow rate ratio of 1/0.3, 1/0.7 and 1/1, respectively. Table 1 summarizes the details of the iCVD experi­ mental conditions.",
        "category": " Materials and methods"
    },
    {
        "id": 8,
        "chunk": "# 2.3. Characterization  \n\nThe film thickness was measured in-situ during the experiments using a laser interferometry, details of which are given elsewhere [26]. The ex-situ measurement of film thickness was conducted using a reflec­ tometer, comprising an Avaspec-ULS2048L spectrometer with an AvaLight-DH-S BAL light source. This was employed to verify the pre­ cision of interferometric thickness measurements. The experiments were repeated three-times and the film thicknesses were measured for each as-deposited films. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analyses were used to reveal the chemical structures of the polymeric films. FTIR spectra were acquired with a resolution of $4~\\mathrm{cm}^{-1}$ using a FTIR spectrometer (Thermo Scien­ tific, Nicolet 380).  \n\nXPS analysis of the polymeric films was carried out by a Specs spectrometer (Specs EA 300) equipped with a monochromatized Al Kα X-ray source. A contact angle goniometer (Krüss Easy Drop) was employed to measure water contact angle values at room temperature using $4.0~\\upmu\\mathrm{l}$ of pure water $\\mathrm{(pH=}7.0\\AA)$ ). The topographical scans of polymeric films were revealed by atomic force microscopy (AFM) (Veeco MultiMode). Two different approaches were applied to test antifogging performances. In the first approach, the samples were placed 4 cm above a hot water bath at $100^{\\circ}\\mathrm{C}$ for $100\\ s.$ . The temperature and relative humidity of the environment were measured as $23.1\\pm1^{\\circ}\\mathrm{C}$ and $55\\pm2\\%$ , respectively. In the second approach, the samples were kept in the freezer part of a refrigerator (Arçelik1060T) for $120\\ s$ and then exposed to open air laboratory environment ${\\cdot}^{\\sim23^{\\circ}\\mathrm{C}}$ and $\\sim30~\\%$ hu­ midity). After the fogging test, a UV–vis spectrophotometer (Shanghai Spectrum Instruments Co., Ltd.) was employed to measure the optical transmission spectra of uncoated and coated glasses in the wavelength range from 400 to $700\\ \\mathrm{nm}$ . In addition, in order to investigate the durability of the anti-fogging properties of the thin films over time, the thin film coated samples were kept in the open air laboratory environ­ ment ( $\\cdot\\sim23^{\\circ}\\mathrm{C}$ and ${\\sim}30\\%$ humidity) for one year and then re-exposed to fog.  \n\n![](images/9c763cc63c9598818345af054d50ae53d8de50848882bcf96108664ef14b404f.jpg)  \nFig. 1. (a) Schematic illustration of iCVD process, (b) iCVD copolymerization reaction of HFBA and DMAEMA.  \n\nTable 1 iCVD experimental conditions for amphiphilic thin film depositions.   \n\n\n<html><body><table><tr><td>Amphiphilic thin films</td><td colspan=\"3\">Flow rate (sccm)</td><td>Reactor pressure (mTorr)</td><td>Filament temperature( °C)</td><td>Substrate temperature (℃)</td></tr><tr><td></td><td>HFBA</td><td>DMAEMA</td><td>TBPO</td><td></td><td></td><td></td></tr><tr><td>AP1</td><td>1.0</td><td>0.3</td><td>1.0</td><td>600</td><td>245</td><td>25</td></tr><tr><td>AP2</td><td>1.0</td><td>0.7</td><td>1.0</td><td>600</td><td>245</td><td>25</td></tr><tr><td>AP3</td><td>1.0</td><td>1.0</td><td>1.0</td><td>600</td><td>245</td><td>25</td></tr></table></body></html>",
        "category": " Materials and methods"
    },
    {
        "id": 9,
        "chunk": "# 3. Results and discussion  \n\nThe deposition rate was calculated as the film thickness divided by the deposition time. Excellent agreement was observed between the film thicknesses measured by interferometer and reflectometer. All iCVD films parameters were kept constant except the DMAEMA flow rates in the fabrication of AP1, AP2 and AP3 thin films. In the AP1 film, where the DMAEMA flow rate $(0.3\\ s c c m)$ was the lowest, the deposition rate was too low to be recorded. When the DMAEMA flow rate increased from 0.3 to 0.7 (AP2), the deposition rate was found to be $27.0\\pm1.3$ $\\mathrm{{nm/min}}$ . When the DMAEMA flow rate was further increased to 1 (AP3), the deposition rate also increased, and reached $35.0\\pm1.8\\mathrm{nm/min}$ . The possible reason for the lower deposition rate of AP2 than that of AP3 may be the higher amount of HFBA in the reactor. The presence of $\\mathrm{CF}_{2}$ and bulky $\\mathrm{CF}_{3}$ groups may have caused a steric effect, resulting in a decrease in the deposition rate [27].  \n\nThe FTIR spectra of AP2 and AP3 films are shown in Fig. 2 in comparison with the spectra of HFBA and DMAEMA monomers. All FTIR spectra were baseline corrected, and thickness normalized. The peak intensities of all spectra were normalized to the observed $\\scriptstyle{\\mathsf{C}}=0$ stretch­ ing at $1760\\mathrm{cm}^{-1}$ in HFBA and DMAEMA monomers [28]. The spectrum of HFBA monomer and copolymers show the following major peak as­ signments: $1288~\\mathrm{cm}^{-1}$ ( ${\\mathrm{-}}\\mathrm{CF}_{2}$ vibration), $962~\\mathrm{cm}^{-1}$ (-CF Vibration) and $892~\\mathrm{cm}^{-1}$ (symmetric ${\\mathrm{-CF}}_{3}$ stretching) [29]. Similarly, the peak at 2840 $\\mathsf{c m}^{-1}$ resulting from the C-H stretching vibration of $\\mathrm{{N}}(\\mathrm{{CH}}_{3})_{2}$ group observed in DMAEMA monomer was also observed in the copolymers [30,31]. These results confirm the presence of functional groups in both monomers in the copolymers. The narrow and distinct peaks in the spectra of the copolymers indicate a high retention of functional groups. Another important point to be noted about the FTIR spectra is that the $\\scriptstyle\\mathbf{C}=\\mathbf{C}$ stretching band observed at the $1635\\mathrm{cm}^{-1}$ peak in both monomers was not observed in the copolymers. The absence of $\\mathtt{C=C}$ double bond in copolymers indicates that the polymerization proceeds through the $\\scriptstyle\\mathbf{C}=\\mathbf{C}$ double bond. In radical polymerization processes performed by wet techniques, additional purification procedures are needed to remove monomer residues. According to FTIR analysis, the absence of any entrained monomer in the copolymers indicates that pure copolymers can be produced by iCVD method without the need for any additional purification process.  \n\n![](images/152ef4fb13b417fda857898d72262344eba7e835c90c0cd083fc2512b21a4230.jpg)  \nFig. 2. FTIR spectra of HFBA, DMAEMA, AP2, and AP3.  \n\nThe compositions of the as-deposited copolymer films were found from the FTIR spectra using the Beer Lambert equation, assuming that the $\\scriptstyle\\mathbf{C}=0$ bond oscillator coefficient is the same in the HFBA and DMAEMA components [32,33]. Eq. (1) was used to calculate the HFBA mole fraction $(f_{\\mathrm{HFBA}})$ in the copolymer film:  \n\n$$\nf_{H F B A}=1-\\left(\\frac{\\mathsf{A}_{C=O}}{\\mathsf{A}_{N(C H_{3})_{2}}}\\right)_{D M A E M A}\\left(\\frac{\\mathsf{A}_{N(C H_{3})_{2}}}{\\mathsf{A}_{C=O}}\\right)_{P(H F B A-D M A E M A)}\n$$  \n\nwhere, $\\scriptstyle\\mathbf{A}_{C=O}$ and $\\mathsf{A}_{N(C H3)2}$ are the area under the $\\scriptstyle\\mathbf{C}=0$ and $\\mathrm{{N}}(\\mathrm{{CH}}_{3})_{2}$ absorption peaks, respectively. HFBA content in AP2 and AP3 was found to be $^{41,3\\ \\%}$ and $33,1\\ \\%$ , respectively. In order to observe this differ­ ence, XPS analysis of the copolymers was performed. The XPS survey scans of AP2 and AP3 are shown in Fig. 3. As expected, only C, O, N and F atoms were detected in both copolymers. It was found that the amount of nitrogen was higher and the amount of fluorine was lower in AP3 film, where the DMAEMA/HFBA monomer flow rate ratio was higher compared to AP2 film.  \n\nIn addition, the chemical bonding of the copolymer films was investigated by high-resolution XPS analysis. High-resolution C1s, O1s, and N1s spectra of AP2 and AP3 films are shown in Fig. 4a–f. The binding energy values in the spectrum of each atom were matched to the experimental data using a curve fitting method. C1s, O1s, and N1s spectra of both thin films can be curve-fitted into eight, two and one peak components, respectively. Observed binding energies in the spectra are given with attributed groups and their theoretical values in Table 2.  \n\nCompared to the spectrum of AP2 (Fig. 4a), the area ratio of the $\\mathrm{CH_{2}\\mathrm{-}C^{\\ast}\\mathrm{-}H F}$ peak in the spectrum of AP3 (Fig. 4b) was lower, while the area ratio of the ${\\bf C}{\\cdot}{\\bf N}^{*}$ peak was higher. Considering the monomer flow rates, the observed difference of both peaks is as expected and in agreement with XPS atomic percentage calculations. Two oxygen moi­ eties present in HFBA and DMAEMA monomer structures were detected in nearly the same positions in both copolymers (Fig. 4c and d) [22,24]. Similarly, nitrogen moiety, which is found only in the structure of DMAEMA monomer, was detected in nearly the same position in both  \n\n![](images/69922b0bd12676e95f9680b4d4667118ad6af2ddae24a3b5272161a12e02f128.jpg)  \nFig. 3. XPS survey spectra of (a) AP2 and (b) AP3.  \n\n![](images/a03524ce4ea2504336ee67c94c67cc9f5f1dc1c7556265c0519471d6a7890034.jpg)  \nFig. 4. High-resolution XPS spectra of C1s for (a) AP2 and (b) AP3; O1s for (c) AP2 and (d) AP3; N1s for (e) AP2 and (f) AP3.  \n\ncopolymers (Fig. 4e and f).  \n\nOne of the desirable properties for anti-fogging coatings is the high homogeneity of the coverage. In order to investigate the homogeneity of the thin films, both copolymers were coated on $5\\cos{\\mathrm{x}}5\\mathrm{cm}$ mirrors with a thickness of $200\\mathrm{nm}$ . The mirrors were divided into 25 different areas, each of which is $1\\mathrm{cm}$ wide and $1\\mathrm{cm}$ long, for contact angle measure­ ments. The measured contact angles for AP2 and AP3 coated mirror surfaces are shown in Fig. 5a and Fig. 5c, respectively. The average contact angle measurements of AP2 and AP3 coated mirrors were calculated as 34.3 and 28.5, respectively. AP2, which has more fluorine atoms in its structure, showed more hydrophobic behavior. Contact angle measurements of both coated mirrors measured at different points were found to be close to each other. The standard deviation values of the contact angle measurements for AP2 and AP3 were 2.6 and 0.8, respectively. These values indicate that both films are homogeneously coated. The results are not surprising, because the CVD method is known for producing very smooth polymeric thin films [34,35]. AFM analysis was conducted to reveal the surface roughness and surface morphology of both copolymer films coated silicon wafers.  \n\nThe AFM images of AP2 and AP3 coated silicon wafers in dimension of $2\\upmu\\mathrm{m}\\times2\\upmu\\mathrm{m}$ are presented in Fig. 5b and Fig. 5d, respectively. The AFM image of both films was observed to be very smooth without any defects and 3D structures. The root mean square roughness values of AP2 and AP3 thin films were measured as $0.256\\ \\mathrm{nm}$ and $0.569\\ \\mathrm{nm}$ , respectively. The AFM images and roughness values of the films confirm that the films were smoothly coated.  \n\nAnother important point related to AFM and contact angle results is the inverse relationship between roughness values and contact angle values. This observation is in agreement with previous studies of hy­ drophilic films produced by PECVD method in the literature [36]. This relationship can be explained by Wenzel model as given in Eq. (2) [37].  \n\nTable 2 High-resolution XPS scan data of AP2 and AP3.   \n\n\n<html><body><table><tr><td colspan=\"2\"></td><td>AP2</td><td>AP3</td><td>Theoretical</td></tr><tr><td>Core level</td><td>Origin</td><td>Binding energy (eV)</td><td>Binding energy (eV)</td><td>Binding energy (eV)</td></tr><tr><td>C 1s</td><td>-C*-C/C-H</td><td>284.6</td><td>284.8</td><td>285.0</td></tr><tr><td></td><td>-C*H-CO-</td><td>285.2</td><td>285.3</td><td>285.5</td></tr><tr><td></td><td>-C*-N</td><td>285.6</td><td>285.7</td><td>285.9</td></tr><tr><td></td><td>-0-C*-H2</td><td>286.5</td><td>286.7</td><td>286.9</td></tr><tr><td></td><td>CH2-CF2-C*-</td><td>287.0</td><td>287.3</td><td>287.9</td></tr><tr><td></td><td>HF-</td><td>289.1</td><td>289.0</td><td>289.2</td></tr><tr><td></td><td>-C*=0-</td><td>291.0</td><td>291.2</td><td>290.9</td></tr><tr><td></td><td>-C*F2</td><td>293.3</td><td>293.5</td><td>293.9</td></tr><tr><td>01s</td><td>-C*F3</td><td></td><td></td><td></td></tr><tr><td></td><td>-C=0*</td><td>531.8</td><td>531.6</td><td>532.4</td></tr><tr><td></td><td>-0*-C</td><td>533.2</td><td>533.0</td><td>533.6</td></tr><tr><td>N1s</td><td>-C-N</td><td>399.0</td><td>399.1</td><td>399.4</td></tr></table></body></html>  \n\n$$\n\\mathrm{cos}\\theta{=}\\mathrm{R_{f}c o s}\\theta_{0}\n$$  \n\nwhere, θ and $\\theta_{0}$ represent the contact angle of a rough surface and flat surface, respectively. ${\\bf R}_{\\mathrm{f}}$ represents the surface roughness factor, defined as the ratio of surface actual area to the geometric surface. For completely smooth surfaces ${\\bf R}_{\\mathrm{f}}$ value should be equal to 1, while for rough surfaces it should be greater than 1. Since $\\theta_{0}$ value of hydrophilic surfaces is less than $90^{\\circ}$ , the contact angle value is expected to decrease with increasing roughness in hydrophilic surfaces. Although the corre­ lation between contact angle results and surface roughness is consistent with the Wenzel model, it should be noted that the roughness values are less than $1\\ \\mathrm{nm}$ . Therefore, it can be postulated that surface chemistry (the amount of fluorinated moieties) has more influence on the wetta­ bility of the surfaces in this study than surface roughness.  \n\nSince there is no significant difference between the chemical and morphological properties of AP2 and AP3 copolymers to affect their anti-fogging performance, the anti-fogging properties of the AP3 thin film which has a higher deposition rate were tested. Anti-fogging coat­ ings applied to optically transmissive or reflective material surfaces must be optically transparent. The UV–vis transmission spectra of the $200~\\mathrm{{nm}}$ thick AP3 film coated glass slide are shown in Fig. 6a in com­ parison with the uncoated glass slide. There is no significant difference between both spectra, indicating that the thin film does not cause any optical loss or absorption in the visible region. In addition, UV–vis transmission spectra of both glass slides were taken immediately after exposure to intense hot water vapor. As can be seen in Fig. 6b, a sharp decrease in the spectrum of the uncoated glass slide was observed due to the effect of the fog formed on the surface. On the other hand, no sig­ nificant difference was observed in the spectra of the glass slide coated with AP3 film before and after exposure to fog, confirming that no fog formed on the surface Fig. 6c shows photographs of uncoated and AP3 film coated glasses exposed to intense hot water vapor. Fig. 6d shows photographs of uncoated and AP3 film-coated mirrors removed from the freezer to room temperature. It is clearly observed that AP3 thin films show successful anti-fogging performance on different surfaces in both conditions. To investigate the long-time durability of the anti-fogging property of the as-deposited thin film produced in this study, the ascoated mirrors were kept in open air laboratory conditions for one year and contact angle measurements were carried out at various time intervals. For the mirror surface coated with AP3 film the contact angle values were found to vary between 27 and 30˚. In addition, no perfor­ mance decrease was observed when the anti-fogging property of the 1- year-old samples was retested. These results show the high durability of the films.  \n\n![](images/2b142c70e0e4cb9bd784a8968dd821f7134bce9328b8a5400696c1cb63922227.jpg)  \nFig. 5. Water contact angle measurements on (a) AP2 and (c) AP3 coated mirros from different locations; AFM images of (b) AP2 and (d) AP3 coated silicon wafers.  \n\n![](images/7e1defda58d49c8b29a118a90837dbb57a2728c47c089bab796fe78a8bd59d23.jpg)  \nFig. 6. UV−vis transmittance spectra of uncoated and AP3 coated glasses before (a) and (b) after fogging tests. Digital photographs of (c) uncoated and AP3 coated glasses, (d) uncoated and AP3 coated mirrors after fogging test.",
        "category": " Results and discussion"
    },
    {
        "id": 10,
        "chunk": "# 4. Conclusion  \n\nP(HFBA-DEAEMA) copolymer thin films were successfully synthe­ sized by iCVD. The iCVD method allowed the fraction of HFBA and DEAEMA incorporation to be systematically varied. All of the asdeposited copolymers were found to exhibit excellent optical trans­ parencies and anti-fogging properties at all monomer fractions studied. According to the water contact angle measurements, coatings were shown to be more hydrophobic with increasing fraction of fluorine atoms in their structures. The as-deposited surfaces showed excellent and long-lasting anti-fogging performance without any significant loss in their optical transparencies. Films were observed to be functional in terms of anti-fogging behavior even after 1-year from the initial coating process, which confirms the durability of the films. This work has shown that anti-fogging coatings can easily be produced via solventless and environmentally friendly iCVD technique on the surfaces of different materials, which can be used in real-world applications. Although very large-area and geometrically complex surfaces may possess some limi­ tations regarding coating uniformities, such limitations can be overcome by carrying out optimization studies at large-scale vacuum deposition systems.",
        "category": " Conclusions"
    },
    {
        "id": 11,
        "chunk": "# CRediT authorship contribution statement  \n\nMelek Dinç Tuna: Writing – original draft, Methodology, Data curation, Conceptualization. Emine Sevgili Mercan: Methodology, Data curation. Mehmet Gürsoy: Writing – original draft, Methodology. Mustafa Karaman: Writing – review & editing, Writing – original draft, Supervision, Funding acquisition, Conceptualization.",
        "category": " References"
    },
    {
        "id": 12,
        "chunk": "# Declaration of competing interest  \n\nThe authors declare that they have no known competing financial  \n\ninterests or personal relationships that could have appeared to influence the work reported in this paper.",
        "category": " Conclusions"
    },
    {
        "id": 13,
        "chunk": "# Data availability  \n\nData will be made available on request.",
        "category": " Conclusions"
    },
    {
        "id": 14,
        "chunk": "# Acknowledgments  \n\nThis study was supported by the Konya Technical University Scien­ tific Research Foundation with a project number of 201016003 and by the Scientific and Technological Research Council of Turkey (TÜB˙ITAK) with a Grant No. of 119M227.",
        "category": " Acknowledgments"
    },
    {
        "id": 15,
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    }
]