Articoli di riviste: "Silica films"

1

Maier, Wilhelm F., Michael Wiedorn e Herbert O. Schramm. "Microporous Silica Films". Angewandte Chemie International Edition in English 30, n. 11 (novembre 1991): 1509–10. http://dx.doi.org/10.1002/anie.199115091.

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Chien, Wen Chen, Yang Yen Yu e Shih Yu Chen. "Synthesis and Characterization of Photopolymerized Poly(acrylic)/Monodispersed Colloidal Silica Hybrid Thin Films". Advanced Materials Research 47-50 (giugno 2008): 662–65. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.662.

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In this study, poly(acrylic)/silica hybrid thin films were prepared from various acrylic monomers and monodispersed colloidal silica with a coupling agent MSMA. The silica content in the hybrid thin films was varied from 0 to 50 wt%. The experimental results showed that the coverage area of silica particle by the MSMA decreased with increasing silica content and resulted in the aggregation of silica particle in the hybrid films. Thus, the silica domain in the hybrid films was varied from 20 to 35 nm by the different mole ratios of MSMA to silica. The results of SEM, TEM, and EA supported the above results. The analysis of FTIR and Raman spectra indicated that the degree of photopolymerization was very high. The prepared hybrid films from the crosslinked acrylic polymer moiety showed much better film uniformity, thermal stability and mechanical properties than those obtained from poly(methyl methacrylate). The refractive index decreased linearly with increasing the silica fraction in the hybrid films. Excellent optical transparency was obtained in the prepared hybrid films. These results showed that the prepared hybrid thin films had potential applications as passive films for optical devices.

3

Deschanels, X., S. Dourdain, C. Rey, G. Toquer, A. Grandjean, S. Pellet-Rostaing, O. Dugne, C. Grygiel, F. Duval e Y. Serruys. "Radiation damages on mesoporous silica thin films and bulk materials". MRS Proceedings 1514 (2013): 69–74. http://dx.doi.org/10.1557/opl.2013.386.

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ABSTRACTMesoporous silicas are highly potential materials for applications in the nuclear field like separation, recycling or nuclear wastes confinement. In this work, the effects of the radiation damage on the mesoporous network were investigated by XRR (X-Rays Reflectivity) and nitrogen adsorption isotherm on respectively mesoporous organized thin films (SBA) and disordered bulk mesoporous materials (Vycor glass). The article attempts to answer the question of the existence of a relationship between the rigidity of the mesoporous silica network, and the behavior of silica materials under irradiation.

4

Li, Yu, Yi He Zhang, Bo Shen e Feng Zhu Lv. "Preparation and Dielectric Properties of Polyimide Nanocomposite Films Based on Hollow Silica". Advanced Materials Research 217-218 (marzo 2011): 647–51. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.647.

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The hollow silica was fabricated by using monodispersed polystyrene microspheres as core template and tetraethyl orthosilicate as silica source, and polyimide nanocomposite films with different hollow silica concentration were successfully prepared via in situ polymerization. The hollow silica and nanocomposite films were characterized. The results indicated that the diameter of the hollow silica is around 30nm and the dielectric constant of the nanocomposite films enhance with the increase of the concentration of the hollow silica.

5

Yu, Yang Yen, Wen Chen Chien e Tsung Wei Tsai. "Microstructure and Properties of Polyimide /Monodispersed Colloidal Silica Hybrid Films Prepared by Sol–Gel Process". Advanced Materials Research 47-50 (giugno 2008): 650–53. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.650.

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In this study, the polyimide-silica hybrid thin films, 6FDA-6FpDA-4ABA/SiO2 (FS0-FS50) were prepared from the 12nm colloidal silica and polyimide bearing acid endgroups. During the preparation, without any additional coupling agents or chelating ligands were used. The strong interactions between carboxylic acid coordinating with silica were believed to prevent the macrophase separation. TGA analysis showed that the thermal decomposition temperatures (Td) incresased with increasing the silica content. UV-VIS spectra showed that the cutoff wavelength of prepared hybrid films could be tunable through the silica content. The n&k analysis showed that the refractive index (n) of PS hybrid films were in the range of 1.575-1.479, which could be controlled by the silica content. The extinction coefficients (k) are almost zero in the wavelength range of 300–900 nm, indicating the prepared hybrid films have an excellent optical transparency in the UV and visible region. TEM images showed that the particle size of silica in the hybrid thin films could be effectively controlled. The results of SEM and AFM showed that all the prepared hybrid films have a good planarity. It demonstrated that the prepared polyimide-silica hybrid thin films have an excellent film formability and planarity.

6

Breval, E., M. L. Mulvihill, J. P. Dougherty e R. E. Newnham. "Polyimide-silica microcomposite films". Journal of Materials Science 27, n. 12 (1992): 3297–300. http://dx.doi.org/10.1007/bf01116027.

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Loughlani, Rayane-Ichrak, Alonso Gamero-Quijano e Francisco Montilla. "Electroassisted Incorporation of Ferrocene within Sol–Gel Silica Films to Enhance Electron Transfer". Molecules 28, n. 19 (28 settembre 2023): 6845. http://dx.doi.org/10.3390/molecules28196845.

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The sol–gel method is a straightforward technique that allows electrode modification with silica thin films. Furthermore, the silica pores could be functionalized to enhance the electrical conductivity and reactivity of the silica films. In this context, silica thin films were functionalized with ferrocene species. This functionalization was performed by electroassisted accumulation, generating a micro-structured composite electrode (Fc@SiO2 electrode). These modified electrodes were characterized by electrochemical and spectroelectrochemical methods, pointing out that ferrocene species were confined with high stability within the microporous silica thin film, demonstrating the good adsorption capacity of the silica. While the spectroelectrochemical characterization indicates that only a fraction of the confined species within the silica films were electroactive, the electrochemical results demonstrate that the Fc@SiO2 film enhances the electrochemical response of cytochrome c in a solution, which gives rise to further applications of these films for redox-controlled release and electrochemical detection of other redox-active proteins.

8

Horikawa, Hajime, Takashi Ogihara, Akio Shimomura e Junko Shimomura. "Preparation and Characterization of Silica Film on PBT Substrate by Sol-Gel Method Using Perhydropolysilazane". Key Engineering Materials 421-422 (dicembre 2009): 161–64. http://dx.doi.org/10.4028/www.scientific.net/kem.421-422.161.

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Silica, silica/polymethylmethacrylate (PMMA) hybrid, and silica-particle blend silica films were successfully prepared on polybutylene terephtalate (PBT) substrate by dip coating using perhydropolysilazane (PHPS) as a silica source. The effect of thermal treatment on conversion from PHPS to silica was investigated in detail by scanning electron microscopy and Fourier transform infrared spectroscopy. Mechanical properties of silica and silica/PMMA hybrid thin films also were examined by the pencil scratch hardness tests.

9

Zhang, Yi He, Qing Song Su, Li Yu, Hong Zheng, Hai Tao Huang, Guo Ge Zhang, Ying Bang Yao e Helen Lai Wah Chan. "Study on the Dielectric Properties of Hybrid and Porous Polyimide-Silica Films". Advanced Materials Research 47-50 (giugno 2008): 973–76. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.973.

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A sol-gel process was used to prepare polyimide-silica hybrid films from the polyimide precursors and TEOS in N,N- dimethyl acetamide, then the hybrid film was treated with hydrofluoric acid to remove the dispersed silica particles, leaving pores with diameters between 80nm to 1µm, depending on the size of silica particles. The structure and dielectric constant of the hybrid and porous films were characterized by FTIR,SEM. The porous films displayed relatively low dielectric constant compared to the hybrid polyimide-silica films.

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Kubo, Tomoko, Eisuke Tadaoka e Hiromitsu Kozuka. "Formation of silica coating films from spin-on polysilazane at room temperature and their stability in hot water". Journal of Materials Research 19, n. 2 (febbraio 2004): 635–42. http://dx.doi.org/10.1557/jmr.2004.19.2.635.

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Spin-coating was conducted on single-crystal silicon substrates using a xylene solution of perhydropolysilazane (PHPS) to obtain 0.14-μm-thick PHPS films. The PHPS films obtained were suspended over various acidic and basic solutions at room temperature so that they were exposed to the vapors from the solutions. PHPS-to-silica film conversion was studied by infrared absorption spectroscopy, and the stability of the exposed films in hot water was examined by soaking the films in 80 °C water. The as-deposited PHPS films were found to be dissolved in water. When the PHPS films were suspended over water, the films were partially converted into silica, but the resultant film had low stability in hot water. Higher degrees of PHPS-to-silica conversion and higher stabilities in hot water were found on exposing the PHPS films to basic or acidic vapors. Exposure to highly basic vapors from aqueous solutions of ammonia and ethylamine was significantly effective in PHPS-to-silica film conversion, which provided silica thin films with high stability in hot water.

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Mahdi, Billal, e Farid Rouabah. "Effect of Titanium Dioxide Nanoparticles on the Properties of Poly(Vinyl Alcohol)/Silica Hybrid Films Prepared by the Sol-Gel Method". Nano Hybrids and Composites 38 (3 febbraio 2023): 63–79. http://dx.doi.org/10.4028/p-381bv9.

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This work is focused on the preparation and characterization of poly (vinyl alcohol)/silica gel/Nano-TiO2, and the study of titanium dioxide (TiO2) nanoparticles (from 1 to 5%) on the properties of poly (vinyl alcohol) (PVA)/silica films. This new material was prepared by the sol-gel method using poly (vinyl alcohol) powder with Tetraethyl Orthosilicate (TEOS) as a precursor source of silica. TEOS was hydrolyzed and condensed in water and ethanol in the presence of hydrochloric acid (HCl) used as a catalyst. Fourier transform infrared (FT-IR), water absorption, water contact angle, ultraviolet-visible spectrometry (UV-VIS), and thermogravimetric analysis (TGA) were used to characterize the hybrid films obtained. The PVA/SiO2/Nano-TiO2 films were successfully synthesized. Owing to the FT-IR Analysis, the chemical bonds have clearly shown that the PVA backbone is linked to the (SiO2-TiO2) network. UV-VIS tests indicated that the hybrid films' UV shielding properties were drastically enhanced as a result of the addition of TiO2. According to the TGA tests, the hybrid films are more heat tolerant than neat PVA films. The water contact angle results revealed that TiO2 nanoparticles used as a doping compound possess an important influence on the hydrophilicity of PVA/SiO2 as thin films. The film's water resistance has also been enhanced.

12

Bi, Wen Yue, Li Wang, Xin Gang Yu, Xing Dong Zhang, Hong Quan Bao e Hui Feng Zhao. "Effect of Heat Treatment on Coloration of Ag Doped TiO₂-SiO₂ Films". Key Engineering Materials 336-338 (aprile 2007): 1793–95. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.1793.

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Silver doped titania-silica films were fabricated by two-step route of sol-gel method using Ti(OC4H9)4, Si(OC2H5)4 and AgNO3 as the precursor materials. The films were annealed at temperature from 350°C to 560°C for a period of time ranging from 15min to 90 min. Optical properties of the films were characterized by UV-visible spectroscopy and the state of silver in the titania-silica films was investigated by XRD patterns. It was found that the annealing temperature and time have considerably influenced the coloration of the films, and with the increase of annealing temperature the [111] orientation of silver crystal occurred which make the color of silver doped titania-silica films deepened. The coloration stability of the silver doped titania-silica films was also investigated.

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Ushijima, Sota, e Toshiyuki Ikoma. "Fabrication of Mesoporous Silica Thin Film Platforms for Surface Reaction with Surface Plasmon Resonance". Key Engineering Materials 758 (novembre 2017): 24–28. http://dx.doi.org/10.4028/www.scientific.net/kem.758.24.

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Mesoporous silica thin films were fabricated on gold substrates with a sol-gel method including a cationic surfactant. The interface of gold and silica thin films was fixed with a mercaptosilane. The surface roughness of the thin films and their grain sizes of silica were both increased with the elimination of the cationic surfactant and polyethylene glycol (PEG) modification on its surface. The surface reaction, adsorption of bovine serum albumin (BSA), was monitored with surface plasmon resonance (SPR). Although the adsorption amount of BSA at 1 mg/mL were 7.9 ng/cm2 on the mesoporous silica, the PEG modification can completely desorb BSA. The mesoporous silica thin films on gold substrates fabricated will be a good platform for analyzing surface reaction.

14

Qin, Xiao Gang, Sheng Sheng Yang, Liang Shi, An Xing e Yuan Gao. "Preparation of Silica Hybrid Films on PMMA by Sol-Gel and Solvothermal Methods". Advanced Materials Research 785-786 (settembre 2013): 877–80. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.877.

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Using solvothermal method to modify the surface of polymethyl methacrylate (PMMA), the silica films were prepared on it via sol solution and solvothermal treatment. Silica-based hybrid sol solutions were synthesized from tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMS). The obtained silica-based hybrid films consisted of the uniform particles around 40 nm in diameter observed by atomic force microscopy (AFM). The optical property was evaluated by the UV-Vis absorption spectra. The silica hybrid films prepared through this process showed good optical transmittance.

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Zhang, Xin, Lei Mao e Jing Ma. "An Investigation on Surface Sol-Gel Silica Film". Advanced Materials Research 787 (settembre 2013): 65–70. http://dx.doi.org/10.4028/www.scientific.net/amr.787.65.

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Ultrathin silica films were grown on polyimide substrates using surface sol-gel method and the film growth process was characterized by ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, Fourier transformed infrared spectroscopy. The polyimide substrates were pretreated by chemical process for promoting the growth of silica film. On the modified polymide surface, the growth of silica films shows an island-like growth type, but not a lay-by-lay process. Moreover, the deposited silica films are not a strict SiO2 film.

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Park, Oun-Ho, Se-Young Seo, Ji-In Jung, Jae Young Bae e Byeong-Soo Bae. "Photoluminescence of mesoporous silica films impregnated with an erbium complex". Journal of Materials Research 18, n. 5 (maggio 2003): 1039–42. http://dx.doi.org/10.1557/jmr.2003.0143.

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Transparent mesoporous silica films were prepared by sol-gel spin coating on silicon wafers at room temperature. An erbium complex, erbium tris 8-hydroxyquinoline (ErQ), was homogeneously impregnated into the pores of the mesoporous silica films, and its concentration was easily controlled by using a solution immersing technique. The ErQ-impregnated mesoporous silica films show a room-temperature photoluminescence at 1.5 µm.

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Yu, Yang Yen, Wen Chen Chien e Chiung Lin Lai. "Preparation and Patterning of Optical Hybrid Thin Films Based on Photosensitive Polyimide and Monodispersed Colloidal Silica". Advanced Materials Research 47-50 (giugno 2008): 654–57. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.654.

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In this study, optical hybrid thin films were prepared from photosensitive poly(4,4-(hexafluoroisopropyl- idenediphthalic anhydride)-co-oxydianiline) (6FDA-ODA)/MDAE and monodispersed colloidal silica with a coupling agent. It was a combination of the sol–gel reaction, thermal polymerization and spin coating. The coupling agents were 3-methacryloxypropyl trimethoxysilane (MPTMS) or (4-vinylphenethyl)trimethoxysilane (VPTMS). The silica content in the hybrid thin films was varied from 0 to 8.6wt%. The coupling agent and the silica domain were designed primarily for reducing the volume shrinkage and enhancing the thermal properties, respectively. The retention of MDAE in the prepared hybrid films is supported by X-ray photoelectron spectroscopy (XPS). The silica domain significantly enhanced the thermal properties of the prepared hybrid films in comparison with parent fluorinated polyimide. The prepared hybrid materials also exhibited reduced refractive index by increasing the silica content. The results of SEM showed the prepared photosensitive hybrid materials could obtain lithographical patterns with a good resolution. These results indicated that the newly prepared photosensitive polyimide/colloidal silica hybrid thin films had potential applications for optical devices.

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Zhang, Rongfei, Xiangyou Wang, Juan Wang e Meng Cheng. "Synthesis and Characterization of Konjac Glucomannan/Carrageenan/Nano-silica Films for the Preservation of Postharvest White Mushrooms". Polymers 11, n. 1 (21 dicembre 2018): 6. http://dx.doi.org/10.3390/polym11010006.

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In this study, the konjac glucomannan (KGM)/carrageenan (KC)/nano-silica film was prepared and characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The preservation quality of white mushrooms (Agaricus bisporus) packed using the films was also determined. The nano-silica dosage was found to affect the properties of the nanocomposite KGM/KC films. The results indicated that the properties of the films were significantly improved with the addition of nano-silica. The water vapor permeability, water solubility, moisture absorption, and light transmittance of KGM/KC/nano-silica films were significantly affected by the nano-silica dosage. In this study, the optimal nano-silica dosage to incorporate into the film in order to achieve excellent performance was 0.3%. Strong intermolecular hydrogen bonds were also observed between KGM/KC and nano-silica in the KGM/KC/nano-silica film by FTIR. In addition, the KGM/KC/nano-silica film markedly reduced the browning index, delayed the weight loss and softening, and extended the shelf life of mushrooms during storage at 4 °C. The KGM/KC film modified using nano-silica can provide a potential method for improving the preservation quality of white mushrooms during storage.

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Guglielmi, M., A. Martucci, R. M. Almeida, H. C. Vasconcelos, E. M. Yeatman, E. J. C. Dawnay e M. A. Fardad. "Spinning deposition of silica and silica-titania optical coatings: A round robin test". Journal of Materials Research 13, n. 3 (marzo 1998): 731–38. http://dx.doi.org/10.1557/jmr.1998.0092.

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A round robin test has been performed on sol-gel processing for the deposition of silica and silica-titania films on silicon substrates by spin-coating. Three solution preparation processes for silica coatings and three for silica-titania coatings were used to prepare samples at each of the participating laboratories. The films have been characterized mainly by thickness (profilometry and ellipsometry measurements), refractive index, porosity, and optical scattering. Different processes gave different thicknesses. Thickness differences were found in films prepared by the same process and by the same deposition parameters, but in different laboratories, when heat-treated at 500 °C. Variations were reduced in samples annealed at 1000 °C. Refractive index and porosity measurements suggest that variations were due to structural differences, particularly porosity. Furthermore, films heat-treated at 500 °C were not completely stabilized, and showed index and porosity variations after six months.

20

He, Jian Yun, Jin Ping Xiong e Bing Qian Xia. "UV-Curable Organic-Inorganic Hybrid Films Based on Epoxynorbornene Linseed Oils". Advanced Materials Research 217-218 (marzo 2011): 294–99. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.294.

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Epoxynorbornene linseed oil (ENLO) is a new kind of epoxide from renewable sources. An UV-curable organic/inorganic hybrid films using epoxynorbornene linseed oils (ENLO) and surface treated nano-silica were formulated. The mechanical properties，thermal properties and coating properties of the ENLO /silica coatings were evaluated as the function of nano-silica content. The results indicated that after incorporating the nano-silica, the strength, modulus and glass transition temperature of the hybrid films enhanced, while the elongation at break decreased. The nano-silica also improved the hybrid coating properties such as pencil hardness, solvent resistance and surface wetting properties. The morphology observation of the films by atomic force microscopy (AFM) showed that the average silica particle size was ~ 70 nm and the particles were well-dispersed in the organic phase.

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Guo, Pei Tao. "Improvement in Mechanical Property of SiO₂ Films Prepared by Sol-Gel". Advanced Materials Research 744 (agosto 2013): 269–72. http://dx.doi.org/10.4028/www.scientific.net/amr.744.269.

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Silica films prepared by the base catalyzed sol–gel process show poor mechanical property. In this study, silica anti-reflective films with good mechanical property have been prepared by the catalyzed sol–gel process with dimethyl formamide added as drying control chemical additives. The silica sol was first dip deposited onto substrate to form films on both sides of the substrate and then subjected to thermal treatment. After thermal treatment, the film was achieved due to the formation of porous structure in the resultant film as a result of decomposing tetraethylorthosilicate and dimethyl formamide. Nano-indenter measurement shows that the Young’s modulus and hardness of base catalyzed films are 10-20GPa and 0.25-0.55GPa, respectively. But the films added with dimethyl formamide are much better than those films derived from base-catalyzed silica sols, the Young’s modulus and hardness are 32-39GPa and 1.22-1.47GPa, respectively. The good mechanical properties make such films potential in both military and civil applications.

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Dhapte, Vividha, Shivajirao Kadam, Varsha Pokharkar, Pawan K. Khanna e Vishwas Dhapte. "Versatile SiO2 Nanoparticles@Polymer Composites with Pragmatic Properties". ISRN Inorganic Chemistry 2014 (29 gennaio 2014): 1–8. http://dx.doi.org/10.1155/2014/170919.

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In the present work, we report the fabrication of silica nanoparticles embedded polymeric (SiO2 nanoparticles@polymer) composite films for numerous traits like texture, folding endurance, crystallinity, size, thermal behavior, spectral analysis, and bioactivity. Significant facets of bulky, inert, inorganic materials are known to burgeon out due to the high surface area of nanosized particles. Nature and proportion of silica nanoparticles as well as polymers exhibited remarkable impact on the fabrication and quality of casted films. Hydrophilic silica nanoparticulate-PVA films depicted better mechanical properties like thermal plus photo stability. Hydrophobic silica nanoparticulate-PMMA films showed qualities of a robust, active, thermostable, antimicrobial material that could resist extreme storage and processing conditions. Overall, these metal oxide nanoparticle-polymer composite films possess qualities reflecting their potential in food, pharmaceutical, and cosmetic industry.

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Zhang, Junrui, Guojun Jiang, Tianhao Huang, Jun Xie e Da Shi. "Preparation and characterization of polyurethane–silica hybrid films". Pigment & Resin Technology 48, n. 5 (2 settembre 2019): 357–62. http://dx.doi.org/10.1108/prt-03-2019-0029.

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Purpose The paper aims to provide a facile approach to the synthesis of polyurethane–silica nanocomposites by introducing self-made aqueous silica sols with different particle sizes into polyurethane materials. This paper investigates the effects of the silica nanoparticles on the polyester polyol, as well as the physical properties and transmittance of the hybrid polyurethane coatings. Design/methodology/approach Colloidal silica particles of different sizes were obtained using a sol–gel process and were then embedded into polyester polyol by in-situ polymerization. These polyester polyol–silica resins were synthesized using an azeotrope process, using xylene to remove the water generated in the system and present in the dispersion medium for the colloidal silica. The polyester polyol–silica resins were further cured using isocyanate trimers to form polyurethane–silica hybrid films. Findings The paper observed that the viscosity of the polyester polyol–silica nanocomposite resins increased and their appearance changed from transparent to ivory white as the particle size of the added silica was increased. It was found that increasing the hydroxyl content of the silica improved the film transmittance in the visible light region. However, the transmittance decreased sharply once the diameter of the silica particles reached 100 nm. Research limitations/implications Because of the limitation of experimental conditions, some performances have not been tested. Therefore, researchers are encouraged to conduct further tests. Practical implications The paper provides a method of preparing hybrid polyurethane film by using silica; the results indicate that the introduction of nano-silica can improve the wear resistance and glass transition temperature of polyurethane coatings. Originality/value The results obtained in this study will be extremely useful to enhance the understanding of organic–inorganic hybrid materials.

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Chauhan, Shobhit Singh, A. L. Sharma e R. V. Jasra. "Photofunctions of Dye Encapsulated Nanostructured Silica Films Suitable for Optical Filter Application". Materials Science Forum 757 (maggio 2013): 257–69. http://dx.doi.org/10.4028/www.scientific.net/msf.757.257.

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The development of nanostructured silica thin films encapsulated with organic functionalities has been an area of active research. The functionalization of films can be done by post doping, covalent or non-covalent methodology. The materials researchers were interested to study and understand the nature of interactions existing in the host silica network and associated physicochemical properties of the derived films. The photofunction imparted films have been explored for chemical and biological sensing applications. In the presented work, an optical filter application based on dye encapsulated nanostructured silica films is reported. To the best of our knowledge, we report for the first time cresol red- a sulfonephthalein dye based nanostructured silica film acting as optical filter. These supported films were found to resemble optical notch filter with center wavelength (CWL) at 432 nm and optical density of 0.05. The films were formed on glass slides by spin coating technique. The coating solution was prepared by template assisted sol-gel method. The films were studied for their physical and chemical characteristics using an array of instrumental techniques.

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Uysal, Bengü Özuğur, e Fatma Z. Tepehan. "Determination of growth kinetics and size dependent structural, morphological, optical characteristics of sol-gel derived silica nanoparticles in silica matrix". Materials Science-Poland 37, n. 1 (1 marzo 2019): 16–24. http://dx.doi.org/10.2478/msp-2019-0010.

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AbstractNanocomposite silica thin films made using the sol-gel method were studied. The nano-silica films were prepared using a mixture of tetraethyl orthosilicate (TEOS), deionized water, ethanol, and ammonia solution. To control the growth of the particles inside the film, the nanocomposite silica film was prepared using a mixture of the nano-silica sol and the silica sol. The change in the particle size with the heat treatment temperature ranging from 450 °C to 1100 °C was investigated. X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), NKD (refractive index-N, extinction coefficient-K, and thickness-D) and ultraviolet-visible (UV-Vis) spectrophotometry were used for characterization purposes. The XRD studies showed that the nano-silica thin films were amorphous at all annealing temperatures except for 1100 °C. The_-cristobalite crystal structure formed at the annealing temperature of 1100 °C. Optical parameters, such as refractive indices and extinction coefficients, were obtained using the NKD analyzer with respect to the annealing temperature of the films. The activation energy and enthalpy of the nanocomposite silica film were evaluated as 22.3 kJ/mol and 14.7 kJ/mol, respectively. The cut-off wavelength values were calculated by means of extrapolation of the absorbance spectra estimated using the UV-Vis spectroscopy measurements. A red shift in the absorption threshold of the nanocomposite silica films indicated that the size of the silica nanoparticles increased with an increase of the annealing temperatures from 450 °C to 900 °C, and this confirms the quantum confinement effect in the nanoparticles.

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Petkov, N., S. Mintova, B. Jean, T. Metzger e T. Bein. "Functionalized cubic mesostructured silica films". Materials Science and Engineering: C 23, n. 6-8 (dicembre 2003): 827–31. http://dx.doi.org/10.1016/j.msec.2003.09.134.

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Urbanova, Veronika, e Alain Walcarius. "Vertically-aligned Mesoporous Silica Films". Zeitschrift für anorganische und allgemeine Chemie 640, n. 3-4 (20 novembre 2013): 537–46. http://dx.doi.org/10.1002/zaac.201300442.

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Alam, S. M. M. "Preparation and Performance of Nano-hybrids Synthesized from Polyimide and Silica". Journal of Scientific Research 2, n. 1 (29 dicembre 2009): 99–107. http://dx.doi.org/10.3329/jsr.v2i1.2733.

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Polyimide (PI)-inorganic like silica hybrid films were successfully prepared to combine the good performances of silica like tensile modulus, thermal stability etc. into organic PI. Polyamic acid (PAA), precursor of PI, was prepared from 3, 3′, 4, 4′-biphenyltetracarboxylic dianhydride (BPDA), p-phenylediamine (PDA) and in-situ formed silica was formed into PAA from tetraethoxysilane (TEOS) through in-situ sol-gel process. The films were transparent and became translucent in presence of up to 10% inorganic contents. The chemical structures were characterized by Fourier transform infrared spectroscopy (FTIR). The morphology of the films was investigated by scanning electronic microscopy (SEM). Differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), stress-strain tests and dynamic mechanical analysis (DMA) were used to evaluate the performances of the films. The results indicated that the glass-transition temperatures (Tg) and decomposition temperatures of the PI-silica hybrid films were higher than those of pristine PI. Tensile modulus, tensile strength of PI increased prominently in presence of small amount (1%) of silica in PI-silica hybrid. Keywords: Polyimide; Hybrid; Sol-gel process. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.2733 J. Sci. Res. 2 (1), 99-107 (2010)

29

Yoon, Seo Young, Sung-Eun Choi e Jin Seok Lee. "Liquid Phase Deposition of Silica on the Hexagonally Close-Packed Monolayer of Silica Spheres". Journal of Nanomaterials 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/510524.

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Liquid phase deposition is a method used for the nonelectrochemical production of polycrystalline ceramic films at low temperatures, most commonly silicon dioxide films. Herein, we report that silica spheres are organized in a hexagonal close-packed array using a patterned substrate. On this monolayer of silica spheres, we could fabricate new nanostructures in which deposition and etching compete through a modified LPD reaction. In the early stage, silica spheres began to undergo etching, and then, silica bridges between the silica spheres appeared by the local deposition reaction. Finally, the silica spheres and bridges disappeared completely. We propose the mechanism for the formation of nanostructure.

30

Innocenzi, Plinio, Luca Malfatti, Barbara Lasio, Alessandra Pinna, Danilo Loche, Maria F. Casula, Valeria Alzari e Alberto Mariani. "Sol–gel chemistry for graphene–silica nanocomposite films". New J. Chem. 38, n. 8 (2014): 3777–82. http://dx.doi.org/10.1039/c4nj00535j.

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Yu, Yang Yen, Wen Chen Chien e Shih Ting Chen. "Preparation of Nanoporous Mondispersed Silica Nanoparticles Films Using Poly(styrene)- Block-Poly( 2-Vinyl Pyridine) as Template". Advanced Materials Research 47-50 (giugno 2008): 646–49. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.646.

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Nanoporous silica films were prepared through the templating of amphiphilic block copolymer, poly(styrene-2-vinyl pyridine) (PS-b-P2VP), and colloidal silica nanoparticles. The experimental and theoretical studies suggested that the intermolecular hydrogen bonding was existed between the colloidal silica nanoparticles and PS-b-P2VP. The miscible hybrid and the narrow thermal decomposition of the PS-b-P2VP led to nanopores in the prepared films from the results of TGA, AFM, and TEM. The effects of the loading ratio and P2VP chain length on the morphology and properties of the prepared nanoporous silica films were investigated. The TEM and AFM studies showed that the uniform pore morphology with pore size 10-15nm was prepared from a modest porogen loading level for the optimum intermolecular hydrogen bonding. The refractive index and dielectric constant of the prepared nanoporous films decreased with an increase in PS-b-P2VP loading. On the other hand, the porosity increased with an increasing PS-b-P2VP loading. This study demonstrated a methodology to control pore morphology and properties of the nanoporous silica films through the templating of PS-b-P2VP.

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He, Chun Qing, K. Ito, Toshitaka Oka, Yoshinori Kobayashi, Toshiyuki Ohdaira e Ryoichi Suzuki. "Argon Plasma Decomposition of Porogen in Mesoporous Silica Films Studied by Positron Annihilation". Materials Science Forum 733 (novembre 2012): 193–96. http://dx.doi.org/10.4028/www.scientific.net/msf.733.193.

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Mesoporous silica films on Si wafers were prepared via a sol-gel process using a triblock copolymer as the structural template. Spin-coated films were dried and subsequently subjected to Ar plasma treatments for decomposing the polymeric porogen. Mesopore formation in the silica film upon Ar plasma treatments was investigated by positron annihilation lifetime spectroscopy. In comparison with calcined silica film, much larger pores, more heterogeneous in size were found in silica film prepared with Ar plasma decomposition of the porogen.

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Sängerlaub, Kucukpinar e Müller. "Desiccant Films Made of Low-Density Polyethylene with Dispersed Silica Gel—Water Vapor Absorption, Permeability (H2O, N2, O2, CO2), and Mechanical Properties". Materials 12, n. 14 (18 luglio 2019): 2304. http://dx.doi.org/10.3390/ma12142304.

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Silica gel is a well-known desiccant. Through dispersion of silica gel in a polymer, films can be made that absorb and desorb water vapor. The water vapor absorption becomes reversible by exposing such films to a water vapor pressure below that of the water vapor pressure during absorption, or by heating the film. The intention of this study was to achieve a better understanding about the water vapor absorption, permeability (H2O, N2, O2, CO2), and mechanical properties of films with dispersed silica gel. Low-density polyethylene (PE-LD) monolayer films with a nominal silica gel concentration of 0.2, 0.4, and 0.6 g dispersed silica gel per 1 g film (PE-LD) were prepared and they absorbed up to 0.08 g water vapor per 1 g of film. The water vapor absorption as a function of time was described by using effective diffusion coefficients. The steady state (effective) water vapor permeation coefficients of the films with dispersed silica gel were a factor of 2 to 14 (8.4 to 60.2·10−12 mg·cm·(cm²·s·Pa)−1, 23 °C) higher than for pure PE-LD films (4.3·10−12 mg·cm·(cm²·s·Pa)−1, 23 °C). On the other hand, the steady state gas permeabilities for N2, O2, and CO2 were reduced to around one-third of the pure PE-LD films. An important result is that (effective) water vapor permeation coefficients calculated from results of sorption and measured by permeation experiments yielded similar values. It has been found that it is possible to describe the sorption and diffusion behavior of water by knowing the permeability coefficient and the sorption capacity of the film (Peff.≈Seff.·Deff.). The tensile stress changed only slightly (values between 10 and 14 N mm−²), while the tensile strain at break was reduced with higher nominal silica gel concentration from 318 length-% (pure PE-LD film) to 5 length-% (PE-LD with 0.6 g dispersed silica gel per 1 g film).

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Liu, Ying-Ling, Chih-Yuan Hsu e Keh-Ying Hsu. "Poly(methylmethacrylate)-silica nanocomposites films from surface-functionalized silica nanoparticles". Polymer 46, n. 6 (febbraio 2005): 1851–56. http://dx.doi.org/10.1016/j.polymer.2005.01.009.

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Domansky, Karel, Jun Liu, Li-Qiong Wang, Mark H. Engelhard e Suresh Baskaran. "Chemical sensors based on dielectric response of functionalized mesoporous silica films". Journal of Materials Research 16, n. 10 (ottobre 2001): 2810–16. http://dx.doi.org/10.1557/jmr.2001.0387.

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Dielectric response of mesoporous silica films was monitored as a function of several gas-phase chemical species. The effects of humidity, ammonia, and methane on dielectric constant and dissipation factor of films subjected to different chemical treatments are described. Dielectric constant and dissipation factor of partially dehydroxylated films were found to be highly sensitive to both water vapor and ammonia in air. The capacitive devices based on mesoporous silica films show potential for use in chemical sensors.

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Tao, Yao, Feng Zheng, Zhao Chen, Shuangshuang Chen, Xuemin Lu e Qinghua Lu. "Comparison of hybrid polyimide films with silica and organosilica obtained via sol–gel process". High Performance Polymers 29, n. 9 (14 settembre 2016): 1049–57. http://dx.doi.org/10.1177/0954008316668242.

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A series of polyimide/silica (PI–S) and polyimide/organosilica (PI–OS) hybrid films were prepared via a sol–gel process from mixtures of poly(amic acid) (PAA) and tetraethoxysilane or a silane coupling agent in solution. The PAA was synthesized from bis-(3-phthalyl anhydride) ether and 1,4-bis (4-aminophenoxy) benzene. The hybrid films were produced via an imidization reaction to form silica particles or a silica network in a polymer matrix through a programmed heating process. The derived films were characterized and compared by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, tensile testing, contact angle measurements, moisture absorption measurements, and dielectric property analysis. Both the PI–S and PI–OS hybrid matrixes showed strong regularity with the increasing silica content and greatly improved thermal stability and mechanical properties. Among them, the PI–OS hybrid films possessed superior interphase interactions and were found to have better physicochemical properties.

37

Ginley, D. S., M. A. Mitchell, J. F. Kwak, E. L. Venturini, R. J. Baughman e W. Fu. "Freestanding thick films of YBa2Cu3O6.9 by screenprinting techniques". Journal of Materials Research 4, n. 3 (giugno 1989): 501–3. http://dx.doi.org/10.1557/jmr.1989.0501.

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Thick (20–300 μm) freestanding polycrystalline films of ceramic YBa2Cu3O6.9 have been obtained by resintering YBa2Cu3O6.9 powder in air after screen printing onto fused silica substrates. An interfacial reaction occurs between the powder and the silica substrate which efficiently detaches the resintered film upon cooling. The magnetization and transport properties of these films are comparable to those for high quality bulk ceramic samples.

38

Astuti, Yayuk, R. A. Yunita Suci Rahayu e Arnelli Arnelli. "Synthesis, Characterization, and Antibacterial Activity Test of Geothermal Silica/AgNO3 Thin Film". Molekul 18, n. 2 (10 luglio 2023): 186. http://dx.doi.org/10.20884/1.jm.2023.18.2.6431.

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Geothermal silica waste offers convenient, economical, and environmentally friendly material with high hydrophobicity to produce thin films. Silica-thin films from geothermal waste using the sol-gel method, though, no addition of AgNO3 was conducted for antibacterial functions. This study aims to produce silica-thin films from geothermal waste with the addition of AgNO3 and analyze the antibacterial activity. The procedures carried out in this research were (i) an acid leaching process using HNO3; (ii) the production of silica thin film with and without the addition of AgNO3; (iii) thin film characterization including a water contact angle measurement (WCA), XRF, FTIR, XRD and SEM-EDX on silica thin film samples with and without the addition of AgNO3; and (iv) antibacterial activity test. The results show the optimum HNO3 concentration for the acid leaching process was 20%, yielding 99.08% SiO2 by mass. The WCA of the silica thin film in the presence and absence of AgNO3 reached a value of ±160°, indicating the addition of AgNO3 did not decrease the contact angle of the silica thin film. This research employed smart deconvolution of IR Spectra using Fityk software which reveals a higher area ratio for Si-O-Si relative to Si-OH. Furthermore, it was observed that the silica thin films exhibited an amorphous morphology, both without and with the addition of AgNO3, with Ag discovered to be dispersed on the thin film. However, despite the presence of Ag, both TF20 and TF20+Ag samples were found to be ineffective in inhibiting bacterial growth, as evidenced by bacteria-free zones on the samples.

39

Park, Hoy Yul, Dong Pil Kang, In Hye Myung e Seog Young Yoon. "Properties of Coating Films Synthesized from Nano Colloidal Silica and Alkoxy Silanes". Materials Science Forum 510-511 (marzo 2006): 222–25. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.222.

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Colloidal silica/silane sol solutions were prepared in variation with the ratio of silane to colloidal silica. Such sol solutions were synthesized from colloidal silica/tetramethoxysilane (TMOS)/methyltrimethoxysilane(MTMS). Sol solutions were prepared by sol-gel reaction through two step reactions. To understand their physical and chemical properties, dip coating of sol solutions was performed on the glass substrates. Contact angle and thickness of coating films increased with increasing the amount of MTMS. The surface free energy of coating films decreased with increasing amount of MTMS. Coating films were stable until 550°C. Thermal degradation temperature of coating films decreased with increasing amount of MTMS. Plastic hardness decreased with increasing amount of MTMS. Elastic portion increased with increasing amount of MTMS.

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Purcar, Violeta, Valentin Rădiţoiu, Florentina Monica Raduly, Alina Rădiţoiu, Simona Căprărescu, Adriana Nicoleta Frone, Cristian-Andi Nicolae e Mihai Anastasescu. "Investigation of Hybrid Films Based on Fluorinated Silica Materials Prepared by Sol–Gel Processing". Coatings 12, n. 10 (20 ottobre 2022): 1595. http://dx.doi.org/10.3390/coatings12101595.

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In this research, fluorinated silica materials were prepared through sol–gel processing with tetraethylorthosilicate (TEOS), triethoxymethylsilane (MTES), and trimethoxyhexadecylsilane (HDTMES), using a fluorinated solution (FS) under acidic medium. The fluorinated solution (FS) was obtained by diluting the perfluorooctanoic acid (PFOA) in 2-propanol. These fluorinated sol–gel silica materials were placed on the glass surfaces in order to achieve the antireflective and hydrophobic fluorinated hybrid films. The structure and surface properties of the final samples were investigated by Fourier transform infrared spectroscopy (FTIR), ultraviolet/visible spectroscopy, thermogravimetric analysis (TGA), atomic force microscopy (AFM), and contact angle (CA) determinations. FTIR spectra demonstrated the presence of a silica network modified with alkyl and fluoroalkyl groups. Thermal analysis showed that the fluorinated sol–gel silica materials prepared with HDTMES have a good thermostability in comparison with other samples. Ultraviolet/visible spectra indicated that the fluorinated hybrid films present a reflectance of ~9.5%, measured at 550 nm. The water contact angle analysis found that the wettability of fluorinated hybrid films was changed from hydrophilic (64°) to hydrophobic (~104°). These hybrid films based on fluorinated sol–gel silica materials can be useful in various electronics and optics fields.

41

Niilisk, Ahti, Mart Moppel, Martti Pärs, Ilmo Sildos, Taavi Jantson, Tea Avarmaa, Raivo Jaaniso e Jaan Aarik. "Structural study of TiO2 thin films by micro-Raman spectroscopy". Open Physics 4, n. 1 (1 marzo 2006): 105–16. http://dx.doi.org/10.1007/s11534-005-0009-3.

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AbstractThe Raman spectroscopy method was used for structural characterization of TiO2 thin films prepared by atomic layer deposition (ALD) and pulsed laser deposition (PLD) on fused silica and single-crystal silicon and sapphire substrates. Using ALD, anatase thin films were grown on silica and silicon substrates at temperatures 125–425 °C. At higher deposition temperatures, mixed anatase and rutile phases grew on these substrates. Post-growth annealing resulted in anatase-to-rutile phase transitions at 750 °C in the case of pure anatase films. The films that contained chlorine residues and were amorphous in their as-grown stage transformed into anatase phase at 400 °C and retained this phase even after annealing at 900 °C. On single crystal sapphire substrates, phase-pure rutile films were obtained by ALD at 425 °C and higher temperatures without additional annealing. Thin films that predominantly contained brookite phase were grown by PLD on silica substrates using rutile as a starting material.

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Drewien, C. A., Y. Lu, C. J. Brinker, R. Ganguli e M. T. Anderson. "Microstructural Analysis of Disordered and Ordered Mesoporous Silica Films". Microscopy and Microanalysis 4, S2 (luglio 1998): 726–27. http://dx.doi.org/10.1017/s1431927600023758.

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Processing can be controlled to produce a family of mesoporous silica films with either disordered, lamellar, hexagonal, or cubic pore distributions[l]. These films, formed by surfactant-templated synthesis and exhibiting a unimodal pore size, promise potential use as inorganic membranes, catalysts, and optically-based sensors[l,2]. The mesoporous films can be formed from initially homogeneous silica sols by a continuous, surfactant-templated process, which relies upon solvent evaporation during the sol-gel dip-coating process. Films of 100-500 nm thick are formed within seconds in a continuous coating operation. The microstructure of the films is dependent upon the cationic surfactant concentration CTAB (CH3(CH2)15N+(CH3)3Br-) and the dip-coating rate. Several films, processed under differing conditions, were investigated by TEM to characterize pore size, structure, and orientation.Figures 1 a & b show the plan view and cross-sectional microstructure of a 2-d hexagonal mesoporous silica film deposited on silicon; the sample was calcined at 400 °C for 3 hours in air. The images were obtained on a Philips CM30 TEM, operated at 300 kV.

43

Li, Zehao, Hui Li, Muxi Wang, Zhongyan Zhang, Liting Yang, Lijun Ma e Hong Liu. "Preparation and Properties of Poly (butylene adipate-co-terephthalate)/thermoplastic Hydroxypropyl Starch Composite Films Reinforced with Nano-Silica". Polymers 15, n. 9 (24 aprile 2023): 2026. http://dx.doi.org/10.3390/polym15092026.

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The use of biodegradable plastics is gradually increasing, but its expensive cost limits promotion. In this study, poly(butylene adipate-co-terephthalate)/thermoplastic hydroxypropyl starch reinforced with nano-silica (PBAT/TPHSg-SiO2) composite films with high hydroxypropyl starch content were prepared in a two-step process. The effect of reinforced thermoplastic hydroxypropyl starch on the mechanical, thermal, processing properties, and micromorphology of the composite films was investigated. The results showed that the tensile strength of the composite films was significantly improved by the addition of nano-silica, with 35% increase in horizontal tensile strength and 21% increase in vertical tensile strength after the addition of 4 phr of nano-silica. When the content of thermoplastic hydroxypropyl starch reinforced with nano-silica (TPHSg-4SiO2) is 40%, the horizontal and vertical tensile strengths of the films are 9.82 and 12.09 MPa, respectively, and the elongation at break of the films is over 500%. Electron micrographs show that TPHSg-4SiO2 is better homogeneously dispersed in the PBAT and exhibits a bi-continuous phase structure at a TPHSg-4SiO2 content of 40%. In this study, the blowing PBAT/TPHSg-4SiO2 composite films effectively reduce the cost and still show better mechanical properties, which are suitable for packaging applications.

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Xu, Wen Cai, Dong Li Li, Ya Bo Fu e Ya Jun Wang. "Influence of Nano-Silica on Solvent Absorption in Polypropylene Packaging". Applied Mechanics and Materials 117-119 (ottobre 2011): 1061–66. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.1061.

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In this paper, the influence of nano-silica on adsorption behavior of solvent in polypropylene packaging is reported. A principle of reducing solvent residue in polypropylene packaging was explored through analyses of changes of crystallization behavior, polarity, and solubility parameters of nano-silica /polypropylene composites. The results showed that the value of solvent residue in modified polypropylene films was reduced about 50%. Therefore nano-silica modified polypropylene films with lower solvent adsorption are in accordance with food safety.

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Xiaowei Zhang, Xiaowei Zhang, Tao Lin Tao Lin, Xiaofan Jiang Jun Xu (Mh) Xiaofan Jiang Jun Xu (Mh), Jianfeng Liu Jianfeng Liu, Ling Xu Ling Xu e Kunji Chen Kunji Chen. "Photoluminescence from Er3+ ion and SnO2 nanocrystal co-doped silica thin films". Chinese Optics Letters 10, n. 9 (2012): 091603–91606. http://dx.doi.org/10.3788/col201210.091603.

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Moon, Kwan, Boknam Chae, Ki Kim, Seung Lee e Young Jung. "Preparation and Characterization of Transparent Polyimide–Silica Composite Films Using Polyimide with Carboxylic Acid Groups". Polymers 11, n. 3 (13 marzo 2019): 489. http://dx.doi.org/10.3390/polym11030489.

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Polyimide (PI) composite films with thicknesses of approximately 100 µm were prepared via a sol–gel reaction of 3-aminopropyltrimethoxysilane (APTMS) with poly(amic acid) (PAA) composite solutions using a thermal imidization process. PAA was synthesized by a conventional condensation reaction of two diamines, 3,5-diaminobenzoic acid (DABA), which has a carboxylic acid side group, and 2,2′-bis(trifluoromethyl)benzidine (TFMB), with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) in N,N-dimethylacetamide (DMAc). The PAA–silica composite solutions were prepared by mixing PAA with carboxylic acid side groups and various amounts of APTMS in a sol–gel process in DMAc using hydrochloric acid as a catalyst. The obtained PI–silica composite films showed relatively good thermal stability, and the thermal stability increased with increasing APTMS content. The optical properties and in-plane coefficient of thermal expansion (CTE) values of the PI–silica composite films were investigated. The CTE of the PI–silica composite films changed from 52.0 to 42.1 ppm/°C as the initial content of APTMS varied. The haze values and yellowness indices of the composite films increased as a function of the APTMS content.

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Thakur, Digvijay B., R. M. Tiggelaar, K. Seshan, J. G. E. Gardeniers e L. Lefferts. "Synthesis of Carbon Nanofibers as Support Layer for Metal Catalyst in a Microreactor for Three-Phase Reactions". Advances in Science and Technology 54 (settembre 2008): 231–36. http://dx.doi.org/10.4028/www.scientific.net/ast.54.231.

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Carbon Nanofibers (CNF) layers were synthesized nickel-based thin-films on flat fused silica substrates. CNF synthesis was performed via thermal catalytic chemical vapor deposition of ethylene using nickel as metal catalyst. Different underlayer metal thin films, viz. titanium, tantalum and titanium-tungsten were tested in order to obtain stable and well-attached CNF films on fused silica substrates. It is found in case of titanium CNFs are formed on the nickel, but due to severe Ni/Ti inderdiffusion the titanium film looses its adhesive function, as a consequence of which the formed CNF film detaches from the substrate. The use of tantalum or titanium-tungsten as adhesion layer resulted in stable and well-adhered CNF films on fused silica substrates, of which the morphology can be controlled by the growth time.

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Kuts, Roman I., Victor P. Korolkov, Ruslan V. Shimansky, Vladimir N. N. Khomutov e Anatoly I. Malyshev. "SUBSTRATE MATERIAL INFLUENCE ON THE THERMOCHEMICAL LASER WRITING OF DIFFRACTIVE STRUCTURES ON ZIRCONIUM FILMS". Interexpo GEO-Siberia 8, n. 1 (8 luglio 2020): 153–59. http://dx.doi.org/10.33764/2618-981x-2020-8-1-153-159.

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The paper is devoted to comparing the features of the formation of oxide microstructures during direct laser writing on thin (100 nm) zirconium films deposited on glass and fused silica substrates to identify the most stable and predicted writing modes. The presence of self-induced oxide quasiperiodic structures was detected during continuous laser writing on zirconium films deposited on glass substrates. The effect of the formation of nanostructures, which are parallel cracks in the oxide layer and have a period equal to the recording step (250-500 nm), formed during the writing process on zirconium films deposited on a quartz substrate is revealed. The advantages of fused silica as a substrate material for direct laser writing on zirconium films are shown due to the higher softening temperature of fused silica compared to glass.

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Pilic, Branka, Tanja Radusin, Ivan Ristic, Clara Silvestre, Vera Lazic, Sebastian Balos e Donatella Duraccio. "Hydrophobic silica nanoparticles as reinforcing filler for poly (lactic acid) polymer matrix". Chemical Industry 70, n. 1 (2016): 73–80. http://dx.doi.org/10.2298/hemind150107015p.

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Properties of poly (lactic acid) (PLA) and its nanocomposites, with silica nanoparticles (SiO2), as filler were investigated. Neat PLA films and PLA films with different percentage of hydrophobic fumed silica nanoparticles (0.2, 0.5, 1, 2, 3 and 5 wt. %) were prepared by solution casting method. Several tools were used to characterize the influence of different silica content on crystalline behavior, and thermal, mechanical and barrier properties of PLA/SiO2 nanocomposites. Results from scanning electron microscope (SEM) showed that the nanocomposite preparation and selection of specific hydrophobic spherical nano filler provide a good dispersion of the silica nanoparticles in the PLA matrix. Addition of silica nanoparticles improved mechanical properties, the most significant improvement being observed for lowest silica content (0.2wt.%). Barrier properties were improved for all measured gases at all loadings of silica nanoparticles. The degree of crystallinity for PLA slightly increased by adding 0.2 and 0.5 wt. % of nano filler.

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Hwang, Young Kyu, Ajit Singh Mamman, K. R. Patil, Lee Kyung Kim, Jin Soo Hwang e Jong San Chang. "Reflectometry Studies of Mesoporous Silica Thin Films". Solid State Phenomena 135 (febbraio 2008): 31–34. http://dx.doi.org/10.4028/www.scientific.net/ssp.135.31.

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Reflectometry technique has been successfully applied to investigate the correlation between the porosity and optical property (refractive index) of the ordered mesoporous thin film deposited on silicon wafer substrates. The measured optical spectra were simulated by the Effective Medium approximation model. The reflectometry technique has been found to be appropriate for the measurement of thickness of thin films as well as thick layer films. The mesoporous silica films prepared from tri-block copolymer (F-127) as a surfactant and polypropylene oxide as a swelling agent were subsequently exposed to the ammonia vapors to enhance thermal stability and shrinkage minimization of the film that results in increased film thickness.

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