我們製備了大小約為5 nm之氧化鋅奈米粒子，並以含壓克力基之矽烷3-(trimethoxysilyl)propylmethacrylate (MPS)進行表面改質。原先僅在乙二醇分散之氧化鋅，經過改質後可得到乾粉，並可再重新分散至許多溶劑。根據紅外光譜及核磁共振分析， MPS是先以tridental 和 monodental 的形式螯合於氧化鋅表面，然後多餘的MPS再接到以monodental 形式螯合的MPS分子外，形成雙層結構。由於粒子表面所接著之矽烷本身帶有壓克力基。若未完全縮合，則又留有氫氧基。所以改質後的氧化鋅不但可以分散至極性較強的溶劑如酒精，亦可分散到極性較弱的溶劑如四氫氟喃和甲基乙基酮。根據小角度X光散射分析，氧化鋅奈米粒子是球型，並在溶劑中會形成動態粒子簇。分散液的黏度隨著奈米粒子濃度的增加而呈現指數成長。其指數值 ~?4代表在高濃度下的粒子可能產生結構。分散液在濃度高達70 wt % 時仍具有高穿透度( T% > 85 )。雖然有流動性但是黏度甚高，是非牛頓流體。我們又製作了氧化鋅/矽膠的奈米複合材料，並塗佈於基材上嘗試作為UV光之阻隔膜。在氧化鋅固含量為65 wt % 而膜厚為5 ?m的情況下，可以將 350 nm以下之UV光完全阻隔，並且在可見光範圍仍呈現高的穿透度。最後我們將這些奈米複合材料進行QUV測試以驗證其耐久性。發現可以在照度高溼氣條件下支撐1400小時。換算成一般戶外條件約可支撐八年。

ZnO nanoparticles (~5 nm) have been prepared and surface-modified with 3-(trimethoxysilyl)propylmethacrylate (MPS). The product is a dry powder which can be re-dispersed in many solvents. Based on the results of IR and NMR analysis, the directly anchored MPS exhibits both tridental and monodental structures, while a second layer of partially condensed silane are linked to the monodental ones. Due to the existence of both methacrylate group and residual hydroxyl, the ZnO@MPS powder can be dispersed in both polar and non-polar solvents. The dispersion remained transparent (T% > 85) and fluidic even at a loading as high as 70 wt %. The viscosity of the dispersion increases exponentially with the filler loading following the Quemada equation. An exponent ~ ?4 confirms that the fillers are un-aggregated even at such a high loading. ZnO/silicone nanocomposites are then prepared and coated on substrates as UV blocking film. A complete blockage of the UV radiation (<350 nm) has been achieved with a 5 ?m coating containing 65 wt% ZnO, while the transparency in the visible range (> 90 T% for >385 nm) could still be maintained. The durability of these nanocomposite films was further investigated by the standard QUV test.

1 Lenz, A. et al. ZnO Nanoparticles Functionalized with Organic Acids: An Experimental and Quantum-Chemical Study. The Journal of Physical Chemistry C 113, 17332-17341, doi:10.1021/jp905481v (2009).
2 Lu, Z. et al. Direct Assembly of Hydrophobic Nanoparticles to Multifunctional Structures. Nano Letters 11, 3404-3412, doi:10.1021/nl201820r (2011).
3 Panigrahi, S., Bera, A. & Basak, D. Encapsulation of 2−3-nm-Sized ZnO Quantum Dots in a SiO2 Matrix and Observation of Negative Photoconductivity. ACS Applied Materials & Interfaces 1, 2408-2411, doi:10.1021/am9005513 (2009).
4 Abboud, M., Turner, M., Duguet, E. & Fontanille, M. PMMA-based composite materials with reactive ceramic fillers. Part 1.-Chemical modification and characterisation of ceramic particles. Journal of Materials Chemistry 7, 1527-1532 (1997).
5 Posthumus, W., Magusin, P. C. M. M., Brokken-Zijp, J. C. M., Tinnemans, A. H. A. & van der Linde, R. Surface modification of oxidic nanoparticles using 3-methacryloxypropyltrimethoxysilane. Journal of Colloid and Interface Science 269, 109-116, doi:10.1016/j.jcis.2003.07.008 (2004).
6 Guo, Z., Pereira, T., Choi, O., Wang, Y. & Hahn, H. T. Surface functionalized alumina nanoparticle filled polymeric nanocomposites with enhanced mechanical properties. Journal of Materials Chemistry 16, 2800-2808 (2006).
7 Rohe, B., Veeman, W. & Tausch, M. Synthesis and photocatalytic activity of silane-coated and UV-modified nanoscale zinc oxide. Nanotechnology 17, 277 (2006).
8 Zhu, M.-Q., Chang, E., Sun, J. & Drezek, R. A. Surface modification and functionalization of semiconductor quantum dots through reactive coating of silanes in toluene. Journal of Materials Chemistry 17, 800-805 (2007).
9 Ma, S.-r., Shi, L.-y., Feng, X., Yu, W.-j. & Lu, B. Graft modification of ZnO nanoparticles with silane coupling agent KH570 in mixed solvent. Journal of Shanghai University (English Edition) 12, 278-282, doi:10.1007/s11741-008-0316-1 (2008).
10 Tang, E. J., Tian, B. Y., Zheng, E. L., Fu, C. Y. & Cheng, G. X. Preparation of zinc oxide nanoparticle via uniform precipitation method and its surface modification by methacryloxypropyltrimethoxysilane. Chem. Eng. Commun. 195, 479-491, doi:10.1080/00986440701707834 (2008).
11 Xu, K., Zhou, S. & Wu, L. Dispersion of [gamma]-methacryloxypropyltrimethoxysilane-functionalized zirconia nanoparticles in UV-curable formulations and properties of their cured coatings. Progress in Organic Coatings 67, 302-310, doi:10.1016/j.porgcoat.2009.10.029 (2010).
12 Kim, D. et al. Preparation and characterization of UV-cured polyurethane acrylate/ZnO nanocomposite films based on surface modified ZnO. Progress in Organic Coatings (2012).
13 Matsuyama, K., Mishima, K., Kato, T., Irie, K. & Mishima, K. Transparent polymeric hybrid film of ZnO nanoparticle quantum dots and PMMA with high luminescence and tunable emission color. Journal of Colloid and Interface Science 367, 171-177, doi:10.1016/j.jcis.2011.10.003 (2012).
14 Jin Kim, D., Hyun Kang, P. & Chang Nho, Y. Characterization of mechanical properties of γAl2O3 dispersed epoxy resin cured by γ-ray radiation. Journal of Applied Polymer Science 91, 1898-1903, doi:10.1002/app.13250 (2004).
15 Bressy, C., Ngo, G. V., Ziarelli, F. & Margaillan, A. New insights into the adsorption of 3-(trimethoxysilyl)propylmethacrylate on hydroxylated ZnO nanopowders. Langmuir, doi:10.1021/la204544c (2012).
16 Chae, D. W. & Kim, B. C. Characterization on polystyrene/zinc oxide nanocomposites prepared from solution mixing. Polymers for Advanced Technologies 16, 846-850, doi:10.1002/pat.673 (2005).
17 Tu, Y. et al. Transparent and flexible thin films of ZnO-polystyrene nanocomposite for UV-shielding applications. Journal of Materials Chemistry 20, 1594-1599 (2010).
18 Demir, M. M. et al. Optical Properties of Composites of PMMA and Surface-Modified Zincite Nanoparticles. Macromolecules 40, 1089-1100, doi:10.1021/ma062184t (2007).
19 Ge, J. et al. Preparation and characterization of PS-PMMA/ZnO nanocomposite films with novel properties of high transparency and UV-shielding capacity. Journal of Applied Polymer Science 118, 1507-1512, doi:10.1002/app.32530 (2010).
20 Paramo, J., Strzhemechny, Y., An lovar, A., igon, M. & Orel, Z. Enhanced room temperature excitonic luminescence in ZnO/polymethyl methacrylate nanocomposites prepared by bulk polymerization. Journal of Applied Physics 108, 023517 (2010).
21 Sun, D., Miyatake, N. & Sue, H. Transparent PMMA/ZnO nanocomposite films based on colloidal ZnO quantum dots. Nanotechnology 18, 215606 (2007).
22 Li, S. et al. Bulk Synthesis of Transparent and Homogeneous Polymeric Hybrid Materials with ZnO Quantum Dots and PMMA. Advanced Materials 19, 4347-4352, doi:10.1002/adma.200700736 (2007).
23 Li, Y., Yang, Y. & Fu, S. Photo-stabilization properties of transparent inorganic UV-filter/epoxy nanocomposites. Composites Science and Technology 67, 3465-3471 (2007).
24 Huang, H.-C. & Hsieh, T.-E. Preparation and characterizations of highly transparent UV-curable ZnO-acrylic nanocomposites. Ceramics International 36, 1245-1251, doi:DOI: 10.1016/j.ceramint.2010.01.010 (2010).
25 Althues, H., Simon, P., Philipp, F. & Kaskel, S. Integration of zinc oxide nanoparticles into transparent poly(butanediolmonoacrylate) via photopolymerisation. J. Nanosci. Nanotechnol. 6, 409-413, doi:10.1166/jnn.2006.010 (2006).
26 Miyazaki, H., Teranishi, Y. & Ota, T. Fabrication of uv-opaque and visible-transparent composite film. Solar Energy Materials and Solar Cells 90, 2640-2646, doi:10.1016/j.solmat.2006.02.030 (2006).
27 Yang, Y. et al. Novel ultraviolet-opaque, visible-transparent and light-emitting ZnO-QD/silicone composites with tunable luminescence colors. Polymer 51, 2755-2762, doi:DOI: 10.1016/j.polymer.2010.03.056 (2010).
28 Sun, Y., Gu, A., Liang, G. & Yuan, L. Preparation and properties of transparent zinc oxide/silicone nanocomposites for the packaging of high power light emitting diodes. Journal of Applied Polymer Science (2011).
29 Li, Y.-Q., Fu, S.-Y. & Mai, Y.-W. Preparation and characterization of transparent ZnO/epoxy nanocomposites with high-UV shielding efficiency. Polymer 47, 2127-2132, doi:DOI: 10.1016/j.polymer.2006.01.071 (2006).
30 Zhao, H. & Li, R. K. Y. A study on the photo-degradation of zinc oxide (ZnO) filled polypropylene nanocomposites. Polymer 47, 3207-3217, doi:10.1016/j.polymer.2006.02.089 (2006).
31 徐志宗. 氧化鋅奈米結晶之製備與分散. 國立中央大學 (2004).
32 Pesika, N. S., Stebe, K. J. & Searson, P. C. Determination of the particle size distribution of quantum nanocrystals from absorbance spectra. Advanced Materials 15, 1289-1291 (2003).
33 Zhao, J. et al. Characterization of Aluminum-Doped Zinc Oxide Nanoparticle Suspensions in Ethylene Glycol for Transparent Conducting Coatings. Journal of the American Ceramic Society 94, 725-728, doi:10.1111/j.1551-2916.2010.04161.x (2011).
34 Vanheusden, K., Seager, C. H., Warren, W. L., Tallant, D. R. & Voigt, J. A. Correlation between photoluminescence and oxygen vacancies in ZnO phosphors. Applied Physics Letters 68, 403-405 (1996).
35 Guo, Z. et al. Particle surface engineering effect on the mechanical, optical and photoluminescent properties of ZnO/vinyl-ester resin nanocomposites. Journal of Materials Chemistry 17, 806-813 (2007).
36 Mueller, R., Kammler, H. K., Wegner, K. & Pratsinis, S. E. OH Surface Density of SiO2 and TiO2 by Thermogravimetric Analysis. Langmuir 19, 160-165, doi:10.1021/la025785w (2002).
37 Sideridou, I. D. & Karabela, M. M. Effect of the amount of 3-methacyloxypropyltrimethoxysilane coupling agent on physical properties of dental resin nanocomposites. Dental Materials 25, 1315-1324, doi:10.1016/j.dental.2009.03.016 (2009).
38 Wisser, F. M. et al. Detection of surface silanol groups on pristine and functionalized silica mixed oxides and zirconia. Journal of Colloid and Interface Science 374, 77-82, doi:10.1016/j.jcis.2012.01.015 (2012).
39 Miller, J. D. & Ishida, H. Quantitative monomolecular coverage of inorganic particulates by methacryl-functional silanes. Surface Science 148, 601-622, doi:10.1016/0039-6028(84)90600-9 (1984).
40 Kotecha, M., Veeman, W., Rohe, B. & Tausch, M. NMR investigations of silane-coated nano-sized ZnO particles. Microporous and Mesoporous Materials 95, 66-75, doi:10.1016/j.micromeso.2006.04.017 (2006).
41 Wang, S.-H. et al. Carboxylic Acid-Directed Clustering and Dispersion of ZrO2 Nanoparticles in Organic Solvents: A Study by Small-Angle X-ray/Neutron Scattering and NMR. The Journal of Physical Chemistry C 115, 11941-11950, doi:10.1021/jp202243z (2011).
42 Hung, C.-H. & Whang, W.-T. Effect of surface stabilization of nanoparticles on luminescent characteristics in ZnO/poly(hydroxyethyl methacrylate) nanohybrid films. Journal of Materials Chemistry 15, 267-274 (2005).
43 Tang, E., Liu, H., Sun, L., Zheng, E. & Cheng, G. Fabrication of zinc oxide/poly(styrene) grafted nanocomposite latex and its dispersion. European Polymer Journal 43, 4210-4218, doi:DOI: 10.1016/j.eurpolymj.2007.05.015 (2007).
44 Teas, J. P. Graphic analysis of resin solubilities. Journal of paint technology 40, 19-25 (1968).
45 Arita, T., Ueda, Y., Minami, K., Naka, T. & Adschiri, T. Dispersion of Fatty Acid Surface Modified Ceria Nanocrystals in Various Organic Solvents. Industrial & Engineering Chemistry Research 49, 1947-1952, doi:10.1021/ie901319c (2009).
46 Quemada, D. Rheology of concentrated disperse systems and minimum energy dissipation principle. Rheologica Acta 16, 82-94, doi:10.1007/bf01516932 (1977).
47 Dames, B., Morrison, B. R. & Willenbacher, N. An empirical model predicting the viscosity of highly concentrated, bimodal dispersions with colloidal interactions. Rheologica Acta 40, 434-440, doi:10.1007/s003970100171 (2001).
48 Chen, H., Ding, Y. & Tan, C. Rheological behaviour of nanofluids. New journal of physics 9, 367 (2007).
49 He, Y. et al. Heat transfer and flow behaviour of aqueous suspensions of TiO2 nanoparticles (nanofluids) flowing upward through a vertical pipe. International Journal of Heat and Mass Transfer 50, 2272-2281, doi:10.1016/j.ijheatmasstransfer.2006.10.024 (2007).
50 Sepeur, S., Kunze, N., Werner, B. & Schmidt, H. UV curable hard coatings on plastics. Thin Solid Films 351, 216-219, doi:10.1016/s0040-6090(99)00339-9 (1999).
51 Althues, H., Henle, J. & Kaskel, S. Functional inorganic nanofillers for transparent polymers. Chemical Society Reviews 36, 1454-1465 (2007).
52 Lowry, M. et al. Assessment of UV-permeability in nano-ZnO filled coatings via high throughput experimentation. Journal of Coatings Technology and Research 5, 233-239 (2008).