[
    {
        "id": 1,
        "chunk": "# Synthesis of UV-curable acrylate polymer containing sulfonic groups for anti-fog coatings  \n\nYan Yuan, Ren Liu, Chunlin Wang, Jing Luo, Xiaoya Liu ∗  \n\nThe Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China",
        "category": " Materials and methods"
    },
    {
        "id": 2,
        "chunk": "# a r t i c l e i n f o  \n\nArticle history:   \nReceived 5 November 2013   \nReceived in revised form   \n10 December 2013   \nAccepted 1 January 2014   \nAvailable online 23 January 2014   \nKeywords:   \nUV-curable   \nSulfonic group   \nAcrylate   \nAnti-fog",
        "category": " Abstract"
    },
    {
        "id": 3,
        "chunk": "# a b s t r a c t  \n\nA series of UV curable hydrophilic acrylate polymers containing sulfonic acid group was prepared via free radical copolymerization using  2-acrylamido-2-methyl propane sulfonic acid  (AMPS)  as  hydrophilic monomer, which were  used  as  prepolymers for  anti-fog coatings. The  expected structures were  confirmed by FT-IR, $^1\\mathrm{H}$ NMR  and  gel permeation chromatography (GPC).  These UV-curable acrylate polymers were then mixed  with reactive diluents and  photoinitiator to  form  coating formulas. Various  substrates were coated with  these  formulas and  cured  under  UV  exposure to  obtain  transparent coatings with  good adhesion and hardness. The anti-fog properties of  UV-cured coating were measured by  contact angle test and anti-fog test. The results showed that  the AMPS content in  prepolymer had a  great  influence on  the anti-fog properties of  UV-cured coating. The formula  was  optimized and the  corresponding UV-curing anti-fog coating was  manufactured. The  test results indicated that  the  coatings showed  good  mechanical properties, great  optical transparency and  excellent anti-fog performance.  \n\n$\\mathfrak{C}$ 2014 Elsevier B.V. All rights reserved.",
        "category": " Abstract"
    },
    {
        "id": 4,
        "chunk": "# 1. Introduction  \n\nWater vapor can condense on solid surface at a certain temperature or humidity, and water on surface forms little droplets if the solid surface has a very high surface energy. Therefore the light is refracted and scattered by water droplets and the transparent materials turn hazy, which causes fogging problems. Many optical devices are suffering from fogging problems, such as eyeglasses, mirrors, windshields and many other devices in special fields [1–4]. There are two efficient ways to solve the problem. One is to heat the device to make water vapor non-condensing, and the other is to provide the solid surface with wetting characteristics such as hydrophilicity [5] or even super hydrophilicity [6]. Although the former method is efficient, the cost of energy limits its wide application.  \n\nHydrophilic surfaces that have contact angles with water of less than $40^{\\circ}$ are often explored as anti-fog coatings. The main reason is that condensing water droplets on this type of surface can rapidly spread into a uniform and non-light-scattering water film [7,8]. In this case, although condensation still occurs, the surface remains optically clear. The key to this approach is the use of materials which can strongly interact with water molecules and/or have a high capacity to absorb water. Hydrophilic polymeric systems containing hydroxyl groups $(\\mathrm{-OH})$ , amino group $\\left(\\mathrm{-NH}_{2}\\right).$ , carboxyl group ( COOH) or sulfonic group $(-S0_{3}\\mathrm{H})$ are often utilized in antifog formulas [9,10]. However, the preparation of optical quality thin-film coatings with these hydrophilic functionalities exhibiting both good coating characteristics and mechanical durability is still a great challenge.  \n\nHerein, a new coating system with good anti-fog properties and mechanical properties was presented. This new coating system was based on a UV-curable hydrophilic polymer which was prepared via free radical copolymerization with 2-acrylamido-2- methyl propane sulfonic acid (AMPS) as hydrophilic monomer. After UV-curing, the resultant coating exhibited good anti-fog properties as well as good mechanical properties.",
        "category": " Introduction"
    },
    {
        "id": 5,
        "chunk": "# 2. Experimental",
        "category": " Materials and methods"
    },
    {
        "id": 6,
        "chunk": "# 2.1. Materials  \n\nMethyl methacrylate (MMA), 2-ethylhexyl acrylate (EHA), 2-hydroxyethyl methacrylate (HEMA), 2-acrylamido-2-methyl propane sulfonic acid (AMPS), isophorone diisocyanate (IPDI), $^{2,2^{\\prime}}$ - azobisisobutyronitrile (AIBN), potassium hydroxide (KOH), methyl alcohol (MeOH), dibutyltin dilaurate (DBTDL), 4-methoxyphenol (MEHQ), acetic ether (EAc), N,N-dimethylformamide (DMF) were all purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China).  \n\n![](images/c7a4642c1b3d33715de204fc6f4e7f129deb1cea9c57d6fc5fad11cd3bfc037a.jpg)  \nScheme 1. The synthetic route of IU-PHEMA.  \n\n1-Hydroxycyclohexyl phenyl ketone (HCPK), 1,6-hexanediol diacrylate (HDDA), ethoxylated trimethylolpropane triacrylate (EOTMPTA), trifunctional acid ester (CD9051), phosphate (w190) were all supplied by Jiangsu Kuangxin Photosensitivity Newmaterial Stock Co., Ltd. (Wuxi, China).",
        "category": " Materials and methods"
    },
    {
        "id": 7,
        "chunk": "# 2.2. Synthesis of prepolymer  \n\nAn isocyanate-containing unsaturated monomer named as HIp was prepared via nucleophilic addition of IPDI and HEMA. The molar ratio of two reactants was 1:1 and the temperature was maintained at $40^{\\circ}\\mathsf C$ .  \n\nA series of sulfo-group-containing acrylate copolymers (PHEMA) were synthesized via free radical copolymerization of AMPS, HEMA, EHA and MMA. AIBN-initiated bulk copolymerizations of monomers were carried out at $90^{\\circ}\\mathsf C.$ . The concentration of AIBN was fixed equal to $2\\times10^{-3}$ mol per mol of all monomers. The prepared PHEMA then reacted with Hip to introduce urethane groups and cross-linkable double bonds into the side chain of polymer, which led to a UV-curable copolymer named as U-PHEMA. Finally, the IU-PHEMA, a prepolymer for antifog coating, was obtained by ionization of U-PHEMA with KOH–methanol solution. The whole synthetic route is shown in Scheme 1.  \n\nIn the experiment, a series of IU-PHEMA prepolymers were prepared to investigate the influence of AMPS content on anti-fog properties. Table 1 shows the amount of each component used in the reaction.  \n\nTable 1 Composition of IU-PHEMA in copolymerization.   \n\n\n<html><body><table><tr><td>No.</td><td>HEMA</td><td>EHA</td><td>MMA</td><td>AMPS</td><td>IPDI</td><td>HEMA</td><td>AMPS%</td></tr><tr><td>IU-PHEMA01</td><td>21.95</td><td>24.72</td><td>11.24</td><td>1.00</td><td>25.00</td><td>16.01</td><td>1%</td></tr><tr><td>IU-PHEMA03</td><td>21.95</td><td>22.72</td><td>11.24</td><td>3.00</td><td>25.00</td><td>16.01</td><td>3%</td></tr><tr><td>IU-PHEMA05</td><td>21.95</td><td>20.72</td><td>11.24</td><td>5.00</td><td>25.00</td><td>16.01</td><td>5%</td></tr><tr><td>IU-PHEMA07</td><td>21.95</td><td>18.72</td><td>11.24</td><td>7.00</td><td>25.00</td><td>16.01</td><td>7%</td></tr><tr><td>IU-PHEMA08</td><td>21.95</td><td>17.72</td><td>11.24</td><td>8.00</td><td>25.00</td><td>16.01</td><td>8%</td></tr><tr><td>IU-PHEMA10</td><td>21.95</td><td>15.72</td><td>11.24</td><td>10.00</td><td>25.00</td><td>16.01</td><td>10%</td></tr></table></body></html>",
        "category": " Materials and methods"
    },
    {
        "id": 8,
        "chunk": "# 2.3. Preparation of anti-fog coating  \n\nThe IU-PHEMA was mixed with photoinitiator and reactive diluents to obtain formulas. HDDA and EOTMPTA were chosen as the reactive diluents to increase the double bond content, and CD9051 and w190 were used to improve the adhesion of formula on glass. Then the formula was coated on clean substrates to obtain a transparent film. The compositions of all formulas were shown in Table 2.",
        "category": " Materials and methods"
    },
    {
        "id": 9,
        "chunk": "# 2.4. Measurements  \n\nThe number-average molecular weight $(M_{\\mathfrak{n}})$ and molecular weight distribution or polydispersity index PDI $(M_{\\mathrm{W}}/M_{\\mathrm{n}})$ of the polymers were determined at $25^{\\circ}\\mathsf{C}$ with WATERS GPC-1515(GPC), using DMF as eluent at a flow rate of $1.0\\mathrm{mL}\\mathrm{min}^{-1}$ . The molecular weight and polydispersity index data were compared against broad standards of PEG. FT-IR spectra were recorded with a Bomem FTLA 2000-104 using the potassium bromide (KBr) disk sampling technique. $^1\\mathrm{H}$ NMR spectrum for IU-PHEMA was obtained by an AVANCE III ${400}\\mathrm{MHz}$ Digital NMR spectrometer at $25^{\\circ}\\mathsf C$ , using DMSO-d6 as solvent.  \n\nTable 2 Composition of UV-curable anti-fog coatings.   \n\n\n<html><body><table><tr><td>Formula</td><td>Resin</td><td>Resin content</td><td>HDDA</td><td>EOTMPTA</td><td>CD9051</td><td>Phosphate</td><td>HCPK</td></tr><tr><td>FA1</td><td>IU-PHEMA01</td><td>70</td><td>10</td><td>10</td><td>5</td><td>2</td><td>3</td></tr><tr><td>FA2</td><td>IU-PHEMA03</td><td>70</td><td>10</td><td>10</td><td>5</td><td>2</td><td>3</td></tr><tr><td>FA3</td><td>IU-PHEMA05</td><td>70</td><td>10</td><td>10</td><td>5</td><td>2</td><td>3</td></tr><tr><td>FA4</td><td></td><td>70</td><td>10</td><td>10</td><td>5</td><td>2</td><td>3</td></tr><tr><td>FA5</td><td></td><td>50</td><td>20</td><td>20</td><td>5</td><td>2</td><td>3</td></tr><tr><td>FA6</td><td>IU-PHEMA07</td><td>40</td><td>25</td><td>25</td><td>5</td><td>2</td><td>3</td></tr><tr><td>FA7</td><td></td><td>30</td><td>30</td><td>30</td><td>5</td><td>2</td><td>3</td></tr><tr><td>FA8</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td></td><td>IU-PHEMA08</td><td>5040</td><td>2025</td><td>2025</td><td>５５</td><td>２2</td><td>33</td></tr><tr><td>FA10</td><td></td><td>50</td><td>20</td><td>20</td><td>5</td><td>2</td><td>3</td></tr><tr><td>FA11</td><td>IU-PHEMA10</td><td>40</td><td>25</td><td>25</td><td>5</td><td>2</td><td>3</td></tr></table></body></html>  \n\nContact angles were measured using a DATA physics OCA40 contact angle goniometer equipped with an environmental chamber. Three drops of water were used for each measurement, and the average contact angle values were reported. Samples for testing were cured on a slide.  \n\nThe coatings are prepared on one side of clean substrates and cured under UV lamp. One part of each substrate is coated and the other part is uncoated. Then samples are held above hot water $(80^{\\circ}\\mathsf{C})$ for 15 s, which is called the anti warm fog test.  \n\nAs comparison, an anti cold fog test is done as follows. The coatings are prepared on both sides of clean substrates and cured under UV lamp. One part of each substrate side is coated and the other part is uncoated. Then the samples are put into a $-15^{\\circ}\\mathsf C$ refrigerator for $10\\mathrm{min}$ and taken out in a $50\\%$ humidity environment.  \n\nTo evaluate the oil resistance of samples, coated panels were immersed in oleic acid at room temperature. To examine the chemical resistance, samples were immersed in $0.5\\mathrm{mol}\\mathrm{L}^{-1}\\mathrm{H}_{2}\\mathrm{S}0_{4}$ , $\\boldsymbol{1}\\mathrm{mol}\\mathrm{L}^{-1}$ NaOH and $50\\%$ ethanol, respectively.",
        "category": " Materials and methods"
    },
    {
        "id": 10,
        "chunk": "# 3. Results and discussion",
        "category": " Results and discussion"
    },
    {
        "id": 11,
        "chunk": "# 3.1. Characterizations of U-PHEMA  \n\nThe FT-IR spectra of PHEMA, HIp and U-PHEMA are shown in Fig. 1. From Fig. 1(a), the absorption peaks of $\\mathsf{C}{=}\\mathsf{C}$ at $1640\\mathsf{c m}^{-1}$ and $\\scriptstyle{\\mathrm{H-C=}}$ at $810\\mathrm{cm}^{-1}$ disappear, which is an evidence that all the monomers have reacted during the copolymerization. Besides, the peak of $s{=}0$ at about $1400\\mathrm{cm}^{-1}$ is observed, indicating the introduction of sulfonic group in the polymer. From Fig. 1(b), the appearance of the characteristic peaks of $\\mathsf{C}{=}\\mathsf{C}$ at $1640\\mathsf{c m}^{-1}$ and $810\\mathrm{cm}^{-1}$ indicates HEMA has successfully reacted with IPDI. As shown in Fig. 1(c), the disappearance of peak at $2236\\mathrm{cm}^{-1}$ indicates the successful reaction between $-\\mathsf{N C O}$ in HIp and $-\\mathsf{O H}$ in PHEMA. What is more, the presence of $\\mathsf{C}{=}{\\mathsf{C}}$ at $1640\\mathrm{cm}^{-1}$ and $\\scriptstyle{\\mathrm{H-C=}}$ at $810\\mathrm{cm}^{-1}$ indicates that photo-crosslinkable double bond has been successfully introduced into the polymer. Fig. 2 shows the $^1\\mathrm{H}$ NMR spectrum of U-PHEMA. The peak a at $7.9\\mathrm{ppm}$ is related to group of $-N\\mathsf{H}-$ , peaks b at 6.1 ppm and $5.8\\mathsf{p p m}$ are assigned to the ${\\mathrm{HC}}{=}{\\mathrm{CH}}$ , and peak c, d and e belong to $\\scriptstyle0=\\mathsf{C}-\\mathsf{C}-\\mathsf{H}$ in the structure of polymer. Based on the above results, it can be concluded that U-PHEMA has been successfully synthesized.  \n\n![](images/0f7504affbe80e35e0190893d64f50252ca356da972ba091d60879e6f9f1ad83.jpg)  \nFig. 1. FT-IR spectra of PHEMA (a), HIp (b), and U-PHEMA (c).",
        "category": " Results and discussion"
    },
    {
        "id": 12,
        "chunk": "# 3.2. Glass transition temperature of IU-PHEMA  \n\nFig. 3 shows the DSC curves of IU-PHEMA with different AMPS content. It can be observed that AMPS content does not have any effects on the glass transition temperature of IU-PHEMA. It can be explained by that the amount of AMPS is not enough to influence the glass transition temperature.",
        "category": " Results and discussion"
    },
    {
        "id": 13,
        "chunk": "# 3.3. Anti-fog test of IU-PHEMA  \n\nTable 3 shows the anti-fog test of UV-cured anti-fog coatings. An overview of Tables 2 and 3 shows that the anti-fog ability of coatings is affected by two major factors. One is the amount of AMPS in IU-PHEMA prepolymers, and the other one is the content of IU-PHEMA in formulas. When the amount of AMPS in IU-PHEMA is above $7\\%$ and the amount of IU-PHEMA in formulas is above $50\\%$ , the coatings exhibit the anti-fog performance. During the UV-curing process, it is likely that the sulfonic groups are trapped in the polymer network, which makes the surface of the film less hydrophilic. Therefore the content of AMPS in prepolymer and the content of prepolymer in formulas have to reach a certain value to ensure sufficient sulfo-group on the surface. Fig. 4 shows the anti-fog tests of formula FA8 on PC plate. It shows that the part with anti-fog coating left keeps good transparency both in anti warm and cold fog tests, which demonstrates the coating prepared by formula FA8 provides the anti-fog performance.  \n\n![](images/f1e31c2ccd858a31063ea6228dfa20ec46a88f063508716eb91c06c2de9db6e7.jpg)  \nFig. 2. $^1\\mathrm{H}$ NMR spectrum of U-PHEMA.  \n\nTable 3 The anti-fog test of UV-cured anti-fog coatings.   \n\n\n<html><body><table><tr><td>Formula</td><td>FA1</td><td>FA2</td><td>FA3</td><td>FA4</td><td>FA5</td><td>FA6</td><td>FA7</td><td>FA8</td><td>FA9</td><td>FA10</td><td>FA11</td></tr><tr><td>Water contact angle</td><td>75</td><td>72</td><td>66</td><td>9.4</td><td>12.4</td><td>54</td><td>59</td><td>11.2</td><td>57</td><td>10.6</td><td>63</td></tr><tr><td>Anti-fog test</td><td>Fogging</td><td>Fogging</td><td>Fogging</td><td>Anti-fog</td><td>Anti-fog</td><td>Fogging</td><td>Fogging</td><td>Anti-fog</td><td>Fogging</td><td>Anti-fog</td><td>Fogging</td></tr></table></body></html>  \n\n![](images/cd93318cc55108f2d60973d609909ec78ee15a0084a5f00e4c10fe8ebe0c54be.jpg)  \nFig. 3. DSC curves of IU-PHEMA with different AMPS content.",
        "category": " Results and discussion"
    },
    {
        "id": 14,
        "chunk": "# 3.4. Mechanical properties of UV-cured anti-fog coatings  \n\nTable 4 gives the film properties of UV-cured anti-fog coatings. Three different transparent substrates (PMMA, PC and glass) were used in the test. It can be seen that the UV-cured coatings exhibit great adhesion and good resistance on various substrates except glass. Although the hydroxyl groups in the IU-PHEMA prepolymer make formulas interact with substrates surface more easily, the surface of glass is so smooth that few resins show a good adhesion on it. The hardness of the coating is an important factor affecting the abrasion and scratch resistance. Hard coatings give better scratch resistance, and abrasion resistance is also affected by surface friction. From Table 4, it is shown that the pencil and pendulum hardness increased with the increasing amount of reactive diluents. The enhancement in hardness can be attributed from the enhanced crosslinking density of the film, which results in higher reactive diluents content in the UV-curing formula. The above results demonstrate that the UV-curing coating with proper formula provides great coating characteristics.  \n\n![](images/a042b10da482d170dbaac83b1dc5879d674599a12bb30b255fb5899882f11600.jpg)  \nFig. 5. UV–vis spectra of three different plates with and without UV-cured coatings.",
        "category": " Results and discussion"
    },
    {
        "id": 15,
        "chunk": "# 3.5. Transparency of UV-cured anti-fog coatings  \n\nTransparency is a key indication for films of anti-fog coatings. Bad transparency limits the film application in optical instruments fields [8]. To evaluate the optical transmission, the UV-cured coatings on various substrates were investigated in the wavelength range of $300{-}800\\mathrm{nm}$ . Fig. 5 shows UV–vis spectra of three different plates with and without UV-cured coatings. For all three substrates, a slight decrease in transmittance with UV-cured coating indicated good transparency of the UV-cured coatings. Besides, the images of the UV-cured coatings on various substrates were also shown in Fig. 6. A clear observation showed that all the prepared UV-cured coatings are totally transparent. Both of the results demonstrate that UV-cured anti-fog coatings with IU-PHEMA have good optical transparency and they can be potential used in transparent optical instruments fields.  \n\n![](images/e0bfa665bba88165b9e718a1ebd93312305b54c8877610d8a6567d45dba4e39b.jpg)  \nFig. 4. Anti-fog tests of formulation FA8 on PC plate. (a) Anti warm fog test and (b) anti cold fog test. The left part of the plate is coated with the anti-fog coating and the right one is without.  \n\nTable 4 The film properties of UV-curing formula of IU-PHEMA.   \n\n\n<html><body><table><tr><td>Formula</td><td>Substrate</td><td>Adhesion/cross-cut</td><td>Pencil hardness</td><td>Pendulum hardness (s)</td><td>Acid resistance</td><td>Alkali resistance</td><td>Ethanol resistance</td><td>Oleic acid resistance</td></tr><tr><td>FA7</td><td>Glass</td><td>２２</td><td>3H</td><td>96</td><td><3 days</td><td><3 days</td><td><3 days</td><td><3 days</td></tr><tr><td>FA6</td><td>Glass</td><td></td><td>3H</td><td>79</td><td><3 days</td><td><3 days</td><td><3 days</td><td><3 days</td></tr><tr><td>FA5</td><td>Glass</td><td>2</td><td>2H</td><td>69</td><td><3 days</td><td><3 days</td><td><3 days</td><td><3 days</td></tr><tr><td></td><td>Glass</td><td>2</td><td>2H</td><td>44</td><td><3 days</td><td><3 days</td><td><3 days</td><td><3 days</td></tr><tr><td>FA4</td><td>PC-plate</td><td>0</td><td>2H</td><td>43</td><td>>10 days</td><td>>10 days</td><td>>10 days</td><td>>10 days</td></tr><tr><td></td><td>PMMA-plate</td><td>0</td><td>2H</td><td>49</td><td>>10 days</td><td>>10 days</td><td>>10 days</td><td>>10 days</td></tr><tr><td>FA8</td><td>PC-plate</td><td>0</td><td>2H</td><td>72</td><td>>10 days</td><td>>10 days</td><td>>10 days</td><td>>10 days</td></tr><tr><td>FA9</td><td>PC-plate</td><td>0</td><td>2H</td><td>83</td><td>>10 days</td><td>>10 days</td><td>>10 days</td><td>>10 days</td></tr><tr><td>FA10</td><td>PC-plate</td><td>0</td><td>2H</td><td>66</td><td>>10 days</td><td>>10 days</td><td>>10 days</td><td>>10 days</td></tr><tr><td>FA11</td><td>PC-plate</td><td>0</td><td>3H</td><td>85</td><td>>10 days</td><td>>10 days</td><td>>10 days</td><td>>10 days</td></tr></table></body></html>  \n\n![](images/9d3b7410a2cc628037807563303a191e3fbde2695b8f8cac7032b047e3c92eea.jpg)  \nFig. 6. The images of three different plates with and without UV-cured coatings. The upper are substrates with UV-cured coating and the lower are clean substrates: (a) glass, (b) PC plate, and (c) PMMA plate.",
        "category": " Results and discussion"
    },
    {
        "id": 16,
        "chunk": "# 4. Conclusion  \n\nIn this article, a new series of UV-curable hydrophilic polyacrylate containing sulfonic groups were synthesized. When the content of AMPS in the prepolymer was over $7\\%$ and the content of prepolymer in the formula was at least $50\\%$ , the UV-cured coatings could achieve anti-fog properties. Also, the formula coated on PC, PMMA and glass plates showed great mechanical properties and good transparency except for bad adhesion on glass plate.",
        "category": " Conclusions"
    },
    {
        "id": 17,
        "chunk": "# Acknowledgements  \n\nThis work was supported by the National Nature Science Foundation of Jiangsu Province (No. BK20130153) and the Fundamental Research Funds for the Central Universities (No. JUSRP1021).",
        "category": " References"
    },
    {
        "id": 18,
        "chunk": "# References  \n\n[1] L. Maechler, C. Sarra-Bournet, P. Chevallier, N. Gherardi, G. Laroche, Plasma Chem. Plasma Process. 31 (2011) 175–187.   \n[2] H.D. Hwang, C.H. Park, J.I. Moon, H.J. Kim, T. Masubuchi, Prog. Org. Coat. 72 (2011) 663–675.   \n[3] S.J. Dain, A.K. Hoskin, C. Winder, D.P. DingsdagdOphthal, Physiol. Opt. 19 (1999) 357–361.   \n[4] P. Chevallier, S. Turgeon, C. Sarra-Bournet, R. Turcotte, G. Laroche, Appl. Mater. Int. 3 (2011) 750–758.   \n[5] N. Nuraje, R. Asmatulu, R.E. Cohen, M.F. Rubner, Langmuir 27 (2011) 782–791.   \n[6] R. Wang, K. Hashimoto, A. Fujishima, M. Chikuni, E. Kojima, A. Kitamura, M. Shimohigoshi, T. Watanabe, Nature 338 (1997) 431–432.   \n[7] F.C. Cebeci, Z. Wu, L. Zhai, R.E. Cohen, M.F. Rubner, Langmuir 22 (2006) 2856–2862.   \n[8] J.A. Howarter, J.P. Youngblood, Macromol. Rapid Commun. 29 (2008) 455–466.   \n[9] D. Radloff, C. Boeffel, H.W. Spiess, Macromolecules 29 (1996) 1528–1534.   \n[10] Y.K. Lai, Y.X. Tang, J.J. Gong, D.G. Gong, L.F. Chi, C.J. Lin, Z. Chen, J. Mater. Chem. 22 (2012) 7420–7426.",
        "category": " References"
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]