Co-reporter:Yuanyang Li;Ke Yang;Bibo Xia;Bowen Yang;Lianghong Yan;Meiying He;Hongwei Yan
RSC Advances (2011-Present) 2017 vol. 7(Issue 24) pp:14660-14668
Publication Date(Web):2017/03/03
DOI:10.1039/C7RA00844A
Antireflective coatings usually suffer from poor functional durability during outdoor service. The incorporation of additional properties, such as broadband antireflection, self-cleaning and mechanical stability, is of great importance. In the current work, we synthesized broadband AR coatings via the design concept of triple-layer interference coating. SiO2–TiO2, TiO2 and nanoporous TiO2–SiO2 composite thin films were employed as bottom, middle and top layers. Substrates (BK-7 glass) coated with the triple-layer films attained consistent high transmittances at 500–700 nm and the average transmittance at that region was 99.4%. The triple-layer films exhibited an outstanding superhydrophilic property with water contact angle of 2° in 0.5 s, and the superhydrophilicity could last for 30 days in the absence of UV illumination. These triple-layer coatings also showed a good ability to decompose organic substances under UV irradiation. The synergistic effect between superhydrophilicity and photocatalysis provides the films with self-cleaning effect. Meanwhile, the abrasion resistance test of the triple-layer films indicated favorable robustness and good adhesion of the films to substrates. This multifunctional film can have potential applications in various areas, like solar cell panels, green houses and architectural glasses.
Co-reporter:Bibo Xia;Jianhui Luo;Yuanyang Li;Bowen Yang;Shuming Zhang
RSC Advances (2011-Present) 2017 vol. 7(Issue 43) pp:26834-26838
Publication Date(Web):2017/05/17
DOI:10.1039/C7RA00622E
Silica coatings with high-transmittance and good environment-resistance properties were prepared by an acid-catalyzed sol–gel method without template. Hexamethyldisilazane (HMDS) was added into an acid-catalyzed silica sol which acted not only as the catalyst but also as a blocking agent. The effect of different contents of HMDS has been investigated. The sponge-like silica coating was obtained when the weight ratio of HMDS to SiO2 was higher than 90%. The addition of HMDS enabled these silica antireflective coatings to possess excellent hydrophobicity properties. When the weight ratio of HMDS to SiO2 was 100%, the silica coating exhibited transmittance as high as 99.64% at a given wavelength and static water contact angle of 143.0°. After 48 hours of environment aging testing at 40%, 60% and 80% RH, these coatings showed a minute decrease upon maximum transmittance, from 99.64% to 99.56%, 99.49% and 99.38%, respectively. The sponge-like HMDS-containing coatings exhibited easy-to-clean properties, which would have great potential application in laser systems.
Co-reporter:Longqiang Ye, Yuanyang Li, Bibo Xia, Yulu Zhang, Bo Jiang
Materials Letters 2016 Volume 176() pp:5-8
Publication Date(Web):1 August 2016
DOI:10.1016/j.matlet.2016.03.006
●An ORMOSIL film with adjustable refractive index from 1.21 to 1.10 was prepared.●The film was prepared at room temperature via template-free sol–gel method.●Heating the film, the refractive index of the film can be decreased to 1.07.●Heating the film, the thickness of the film will also be change.A nanoporous organically modified silicate (ORMOSIL) film with adjustable refractive index from 1.21 to 1.10 was prepared at room temperature via a template-free sol–gel method, using tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) as co-precursors and hexamethylisilazane (HMDS) as surface modifier. Heating the ORMOSIL film, the refractive index of the ORMOSIL film can be further decreased to as low as 1.07. This adjustable refractive index thin film can find potential application in optical and microelectronic fields.
Co-reporter:Longqiang Ye;Xinxiang Zhang;Yulu Zhang
Journal of Sol-Gel Science and Technology 2016 Volume 80( Issue 1) pp:1-9
Publication Date(Web):2016 October
DOI:10.1007/s10971-016-4051-y
A three-layer tri-wavelength broadband antireflective (AR) coating with 100 % transmittance simultaneously at 1064, 532 and 355 nm was designed using TFCalc™ thin film design software. The refractive indices for the bottom, middle and top layers of the designed AR coating are 1.33, 1.21 and 1.10, respectively. To realize the designed AR coating, a template-free sol–gel process was proposed to regulate the refractive index of silica film from 1.09 to 1.44 by simple hybridization. Silica films with refractive index of 1.21–1.44 were prepared by the hybridization of acid-catalyzed silica and base-catalyzed silica, while organically modified silicates films with refractive index of 1.09–1.21 were prepared by the hybridization of tetraethoxysilane, methyltriethoxysilane and hexamethyldisilazane under base-catalyzed condition. These two hybridization methods could conveniently control the porosity, and hence the refractive index of films. Finally, the three-layer tri-wavelength broadband AR coating, which is very important in high-power laser systems, was realized with the transmittance of 99.9, 99.8 and 99.4 % at 1064, 532 and 355 nm, respectively.
Co-reporter:Yuanyang Li, Haibing Lv, Longqiang Ye, Lianghong Yan, Yulu Zhang, BiBo Xia, Hongwei Yan and Bo Jiang
RSC Advances 2015 vol. 5(Issue 26) pp:20365-20370
Publication Date(Web):03 Feb 2015
DOI:10.1039/C4RA17141A
Porous silica films with a refractive index varying from 1.44 to 1.15 were prepared and applied to realize a double-layer broadband AR coating. The porous silica films were obtained using tetraethylorthosilicate (TEOS) as precursor and a binary template as porogen which was composed of cetyltrimethylammonium bromide (CTAB) and polypropylene glycol (PPG). The molar ratio of the two templates was optimized, and a hypothetical mechanism for the cooperative assembly of silicates with the binary template system was proposed. The two layers had the same skeleton despite different porosity with the top layer much more porous than the bottom one. The double-layer double-wavelength AR coating had excellent optical properties with transmittances of 99.6% and 99.8% at 532 nm and 1064 nm, respectively.
Co-reporter:Shuang Cai, Qinglan Xue, Bibo Xia, Jie Yang, Hai-bing Lv, Hong-wei Yan, Bo Jiang
Materials Letters 2015 Volume 156() pp:14-16
Publication Date(Web):1 October 2015
DOI:10.1016/j.matlet.2015.04.110
•Hydrophobic–oleophobic AR film with well optical property was prepared.•Incorporation of acid MTES sol enhances the abrasion-resistance of the AR films.•Methyl groups improve the liquid-repellent of the film and AR stability.A single layer SiO2 hydrophobic–oleophobic antireflective (AR) film with excellent optical property was prepared by simply mixing the base-catalyzed tetraethylorthosilicate (TEOS) sol with acid-catalyzed methyltriethoxysilane (MTES) sol. When the weight ratio of acid-catalyzed MTES sol to total hybrid sol reaches to 70%, a hydrophobic–oleophobic AR film with a high transmittance of 98.89% at 550 nm can be obtained. The water contact angle and the oil contact angle of the film are 120.6° and 78.4°, respectively. No obvious reduction in the maximum transmittance of prepared single layer SiO2 hydrophobic–oleophobic antireflective film at about 550 nm can be observed after abrasion or exposure to the outdoor condition for four months, demonstrating its great application potential in the outdoor devices.
Co-reporter:Shuang Cai, Yulu Zhang, Hongli Zhang, Hongwei Yan, Haibing Lv, and Bo Jiang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 14) pp:11470
Publication Date(Web):June 30, 2014
DOI:10.1021/am501972y
Hydrophobic antireflective coatings with a low refractive index were prepared via a base/acid-catalyzed two-step sol–gel process using tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as precursors, respectively. The base-catalyzed hydrolysis of TEOS leads to the formation of a sol with spherical silica particles in the first step. In the second step, the acid-catalyzed MTES hydrolysis and condensation occur at the surface of the initial base-catalyzed spherical silica particles, which enlarge the silica particle size from 12.9 to 35.0 nm. By a dip-coating process, this hybrid sol gives an antireflective coating with a refractive index of about 1.15. Moreover, the water contact angles of the resulted coatings increase from 22.4 to 108.7° with the increases of MTES content, which affords the coatings an excellent hydrophobicity. A “core–shell” particle growth mechanism of the hybrid sol was proposed and the relationship between the microstructure of silica sols and the properties of AR coatings was investigated.Keywords: core−shell; MTES; TEOS; two-step
Co-reporter:Yulu Zhang, Chaoxia Zhao, Pingmei Wang, Longqiang Ye, Jianhui Luo and Bo Jiang
Chemical Communications 2014 vol. 50(Issue 89) pp:13813-13816
Publication Date(Web):15 Sep 2014
DOI:10.1039/C4CC05397D
Silica coatings with refractive indices as low as 1.10 were prepared via a one-step base-catalysed sol–gel process using methyltriethoxysilane and tetraethoxysilane as co-precursors. No expensive equipment was required and the method did not require etching or high-temperature calcination.
Co-reporter:Longqiang Ye, Shuming Zhang, Qing Wang, Lianghong Yan, Haibing Lv and Bo Jiang
RSC Advances 2014 vol. 4(Issue 67) pp:35818-35822
Publication Date(Web):18 Jul 2014
DOI:10.1039/C4RA05309E
A single-layer antireflective (SLAR) coating with extremely high photovoltaic transmittance (TPV) at 400–1100 nm was designed with the aid of thin film design software (TFCalc™). The AR coating was prepared by evaporation-induced self-assembly using tetraethylorthosilicate (TEOS) as precursor and cetyltrimethylammonium bromide (CTAB) as template. The measured PV transmittance reaches as high as 98.7%, which is in good agreement with the theoretical value. Meanwhile this SLAR coating has excellent mechanical robustness, which passed the 3H pencil hardness test and abrasion test. This SLAR coating with high transmittance and good mechanical properties will find important application in the field of solar cells.
Co-reporter:Qiong Chen;Xiaoxiao Han;Shuhua Peng;Jianping He;Mingyu Deng;Yongchao Zhao
Journal of Applied Polymer Science 2014 Volume 131( Issue 13) pp:
Publication Date(Web):
DOI:10.1002/app.40460
ABSTRACT
A novel N,O-carboxymethyl hydroxypropyl chitosan (HPCMS) derivative was prepared by a two-step reaction. Water-soluble hydroxypropyl chitosan (HPCS) with a degree of substitution of hydroxypropyl higher than 0.8 was first synthesized by the reaction of chitosan (CS) with propylene oxide (PO) with alkali as a catalyst. Then, amphoteric chitosan derivatives (HPCMS) with a degree of substitution of carboxymethyl ranging from 0.42 to 1.38 were prepared by the reaction of HPCS with chloroacetic acid in an aqueous solution with alkali as a catalyst. The structures of the polymers were characterized by Fourier transform infrared spectroscopy and NMR; this showed that the hydroxypropylation mainly occurred on the OH groups at the C-6 of CS in the reaction of CS with PO. In the reaction of HPCS with chloroacetic acid, both the OH and NH2 groups of HPCS were susceptible to the carboxymethylation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40460.
Co-reporter:Bibo Xia;Qinghua Zhang;Songyuan Yao
Journal of Sol-Gel Science and Technology 2014 Volume 71( Issue 2) pp:291-296
Publication Date(Web):2014/08/01
DOI:10.1007/s10971-014-3362-0
Silica antireflective (AR) coatings with high transmittance and enhanced abrasion-resistance were synthesized by sol–gel process using polypropylene glycol (PPG) as porogen. The effects of molecular weight of PPG and weight ratio of PPG to SiO2 on the refractive index and abrasion-resistance of the coating were systematically studied and compared with those of polyethylene glycol (PEG). Experimental data showed that the refractive index decreased with increasing the weight ratio to SiO2 and molecular weight of both PEG and PPG, but PPG was much more effective than PEG. In the case of same molecular weight, PPG modified coating has the higher porosity than PEG modified one. When the weight ratio of PPG to SiO2 is in a low level, the PPG-containing silica AR coatings exhibit the good abrasion-resistance. PPG is liquid at room temperature and the better solubility than PEG. These effective and economic AR coatings with enhanced abrasion-resistance have potential value in the field of solar thermal collectors.
Co-reporter:Xin-Xiang Zhang;Shuang Cai;Dan You;Liang-Hong Yan;Hai-Bing Lv;Xiao-Dong Yuan
Advanced Functional Materials 2013 Volume 23( Issue 35) pp:4361-4365
Publication Date(Web):
DOI:10.1002/adfm.201203059
Abstract
A double-layer double-wavelength antireflective (AR) coating with 100% transmittance at both 1064 nm and 532 nm, which is very important in high power laser systems, is designed using thin film design software (TFCalc). The refractive indices for the bottom and top layers of the designed AR coating are about 1.30 and 1.14. A simple, template-free sol-gel route is proposed to prepare the superhydrophobic ORMOSIL (organically modified silicate) thin film, which has an ultralow refractive index, by silica particle surface modification using hexamethylisilazane (HMDS); this treatment decreases the refractive index of the silica thin film from 1.23 to 1.13. The formation mechanism of the ultralow refractive index thin film is proposed. The particle surface modification with HMDS significantly improves the hydrophobicity of the coated film; the water contact angle of the film increases from 23.4° to 160°. The bottom layer, which has a refractive index of 1.30, is prepared from acid-catalyzed and base-catalyzed mixed silica sol. A double-layer silica AR coating is obtained with transmittances of 99.6% and 99.8% at 532 nm and 1064 nm, respectively.
Co-reporter:Longqiang Ye, Yulu Zhang, Xinxiang Zhang, Teng Hu, Rui Ji, Bin Ding, Bo Jiang
Solar Energy Materials and Solar Cells 2013 Volume 111() pp:160-164
Publication Date(Web):April 2013
DOI:10.1016/j.solmat.2012.12.037
Triple-layer broadband abrasion-resistant antireflective (AR) coatings with excellent transmittance at 400–800 nm were designed with the aid of thin film design software (TFCalc™). SiO2, TiO2 and SiO2–TiO2 hybrid thin films with refractive indices of 1.44, 2.20 and 1.71 for the up, middle and bottom layers, were dip-coated from SiO2, TiO2 and SiO2–TiO2 hybrid sols by sol–gel process, respectively. SiO2 and TiO2 sols were prepared using tetraethyl orthosilicate (TEOS) and tetrabutyl orthotitanate (TBOT) as precursors and hydrochloric acid as catalyst. These designed triple-layer broadband AR coatings with an average transmittance as high as 98.4% at visible region were successfully obtained. Hexamethyldisilazane (HMDS) was further used to modify the surface of the AR coatings, which greatly improved the hydrophobicity of the coatings, and thus gave the AR coatings some self-cleaning property. These triple-layer abrasion-resistant broadband AR coatings with excellent transmittance in the visible region have potential value in the field of solar cells.Highlights► A tri-layer broadband AR coating was designed with the thin film design software (TFCalc™). ► The experimental average transmittance reached 98.4% in the region of 400–800 nm. ► The coating exhibits good abrasion-resistance.
Co-reporter:Xinxiang Zhang, Bibo Xia, Bin Ding, Yulu Zhang, Jianhui Luo, Bo Jiang
Materials Letters 2013 Volume 104() pp:31-33
Publication Date(Web):1 August 2013
DOI:10.1016/j.matlet.2013.04.016
•We proposed an ultra-fast surface modifying method for sol–gel silica AR film.•Poly(methylhydrogen)siloxane significantly increased the hydrophobicity.•Poly(methylhydrogen)siloxane increased simultaneously the abrasion-resistance.•Increasing chain length will increase the abrasion-resistance more effectively.A novel and ultra-fast route was proposed to modify the surface hydrophobicity of sol–gel silica antireflective (AR) coating with poly(methylhydrogen)siloxane (PMHS). The hydroxyl groups on silica particle are thought to react with the hydrogen atoms within several seconds at room temperature in the presence of platinum catalyst. The surface modification can be accomplished simply by immerging silica AR coating into the PMHS/hexane solution containing platinum catalyst and then withdrawing immediately from the solution. The hydrophobicity and abrasion-resistance of PMHS modified AR coating were significantly improved. This provides a new method for the preparation of abrasion-resistant sol–gel silica AR coating used in outdoor environment.
Co-reporter:Yongchao Zhao, Jianping He, Xiaoxiao Han, Xiulin Tian, Mingyu Deng, Weiping Chen, Bo Jiang
Carbohydrate Polymers 2012 Volume 90(Issue 2) pp:988-992
Publication Date(Web):1 October 2012
DOI:10.1016/j.carbpol.2012.06.032
A new guar gum derivative containing amino group was synthesized through nucleophilic substitution of p-toluenesulfonate activated hydroxypropyl guar gum with ethanolamine. For the preparation of p-toluenesulfonate esters hydroxypropyl guar gum, the results showed that the reaction rate was optimal at 25 °C and the reaction could reach equilibrium state when it was carried out for 10 h at 25 °C. For the nucleophilic substitution of tosyl group with ethanolamine, the reaction was completed after 10 h reaction at 50 °C. The structures of products were characterized by NMR and FT-IR spectroscopy. The results showed that the p-toluenesulfonate esters can be effectively substituted by ethanolamine to form the hydroxyethyl amino hydroxypropyl guar gum (EAHPG). The content of nitrogen of EAHPG was determined by acid–base titration and element analysis.Highlights► A new guar gum derivative containing amino group is synthesized. ► The tosylation reaction occurs mostly at hydroxyl groups of hydroxypropyl. ► The formed tosyl groups can be displaced easily by ethanolamine. ► The reaction condition is easy to be controlled.
Co-reporter:Hong-Zhi Ma, Xiao-Wei Yu, Cong Song, Qing-lan Xue, Bo Jiang
Journal of Molecular Catalysis B: Enzymatic (May 2016) Volume 127() pp:76-81
Publication Date(Web):1 May 2016
DOI:10.1016/j.molcatb.2016.02.014
•Epoxy modified silica with large pore volumes by sol-gel process.•Adsorption amount of CALB on F-560-S was 6.5 times larger than that on U-S.•The greatly improved reusability and stability of CALB on F-560-S were observed.An epoxy-functionalized silica support was prepared through 3-glycidoxypropyltrimethoxylsilane(KH560)modified silica sol in the presence of triblock copolymer F127 (F-560-S). The surface chemistry, micromorphology and pore structure of the supports were characterized by TG, FTIR, SEM and N2 adsorption-desorption, which showed that the BET surface areas and pore volumes of epoxy-activated supports increased with the addition of F127. The Candida Antarctica Lipase B (CALB) was immobilized on the resulting carrier by covalent link. The lipase absorbed amounts were 58 mg/g support and 375 mg/g support on the normal silica (N-S) and modified silica (F-560-S), respectively. The immobilized lipases were examined as biocatalysts for transesterification of 1-phenethanol and vinyl acetate in nonaqueous medium. Solvents and temperature were investigated for influence of morphology and KH560 on the immobilized lipase. The catalytic activity of the CALB immobilized on F-560-S was improved in various solvents, especially in polar solvents. The immobilized CALBs maintained high activity, while the control experiment using free lipase gave very low ester production in the temperature range of 0–60 °C. Furthermore improved thermal stability of CALB immobilized on F-560-S compared to the CALB on N-S was observed. The CALB immobilized on F-560-S exhibited high operational stability in organic media which still retained 88.3% of its original activity for 12 h consecutive 7 runs.Download full-size image
Co-reporter:Yulu Zhang, Chaoxia Zhao, Pingmei Wang, Longqiang Ye, Jianhui Luo and Bo Jiang
Chemical Communications 2014 - vol. 50(Issue 89) pp:NaN13816-13816
Publication Date(Web):2014/09/15
DOI:10.1039/C4CC05397D
Silica coatings with refractive indices as low as 1.10 were prepared via a one-step base-catalysed sol–gel process using methyltriethoxysilane and tetraethoxysilane as co-precursors. No expensive equipment was required and the method did not require etching or high-temperature calcination.
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