热处理温度对Co_(0.8)Fe_(2.2)O_4/SiO_2纳米复合薄膜结构和磁性能的影响

采用溶胶-凝胶旋涂法在经表面氧化的Si(100)基片上制备了Co0.8Fe2.2O4/Si O2纳米复合薄膜。利用X射线衍射仪、扫描电子显微镜和振动样品磁强计对Co0.8Fe2.2O4/Si O2纳米复合薄膜的结构、形貌和磁性能进行分析,研究了热处理温度对复合薄膜结构和磁性能的影响。结果表明:热处理温度高于750℃时复合薄膜中Co0.8Fe2.2O4呈现尖晶石结构;当热处理温度从750℃升高到1 100℃,复合薄膜中Co0.8Fe2.2O4的晶粒尺寸从6 nm增大到34 nm,晶胞常数从0.836 9 nm增大到0.839 5 nm。样品的矫顽力随热处理温度的升高先增大后减小,经1 000℃热处理样品的矫顽力达到298.3 k A/m。     

有序介孔二氧化硅薄膜的制备及性能

以十六烷基三甲基溴化铵(CTAB)为模板剂,正硅酸乙酯为无机前驱体,在酸性条件下,采用溶胶-凝胶技术,用蒸发诱导自组装(EISA)工艺制备了二氧化硅透明介孔薄膜. 透射电子显微镜图显示热处理后的薄膜具有高度有序的六方相结构孔道;由椭偏仪测得热处理后薄膜的折射率低至1.18,厚度在180 nm左右;阻抗分析仪测得薄膜的介电常数为2.14. 薄膜经过六甲基二硅胺烷(HMDS)表面修饰后具有良好的疏水性能和热稳定性,作为低介电材料能更好满足工业需求.     

溶胶-凝胶法制备TiO2-SiO2复合薄膜的波导特性研究

研究了采用溶胶－凝胶法制备的ＴｉＯ２－ＳｉＯ２复合薄膜的波导特性。结果表明随着ＴｉＯ２含量和热处理温度的提高,薄膜的波导损耗增大。ＦＴ－ＩＲ光谱,ＸＲＤ和ＡＦＭ分析表明：这种损耗主要来自于薄膜中的微区不均匀和由于薄膜表面的粗糙度增大而产生的光散射的影响。通过航向光谱计算得到了薄膜的折射率和消光系数和色散关系以及它们与工艺之间的关系。     

高导电纳米银/聚酰亚胺复合薄膜的制备及其性能研究

通过对聚酰亚胺(PI)薄膜进行碱溶液水解、离子交换和热处理制备出具有表面导电性的聚酰亚胺银复合薄膜,并研究了影响聚酰亚胺银复合薄膜导电性的因素。结果表明,一定的薄膜厚度、碱溶液处理时间、合适的固化时间和固化温度都有利于制备出高导电性的复合薄膜。该复合薄膜保持了聚酰亚胺薄膜的基本力学性能,并且银原子与聚合物之间有良好的黏附性能。该制备方法简单,成本低,易于大规模生产。     

烧结温度对不锈钢表面溶胶-凝胶ZrO2纳米薄膜摩擦学性能的影响

采用溶胶-凝胶法,在304不锈钢表面制备了分别经500℃、600℃和700℃下热处理的ZrO2薄膜.利用X射线衍射仪(XRD)、原子力显微镜(AFM)、扫描电镜(SEM)和摩擦磨损测试仪,研究了热处理温度对ZrO2薄膜的表面结构和摩擦学性能的影响.结果表明:随着温度的升高,ZrO2晶体结构逐渐由四方相(t-ZrO2)向单斜相(mZrO2)转变;当热处理温度从500℃升高到700℃时,ZrO2薄膜的平均晶粒度略有增大,但都在80 nm左右,晶粒分布趋于均匀致密,且其表面粗糙度由6.3 nm降低至4.6 nm左右.同时ZrO2薄膜的摩擦系数和磨损率分别从0.22和2.24×10-4mm3/Nm逐渐减小为0.19和1.95×10-4 mm3/Nm,因而薄膜的抗磨减摩性能也显著提高.     

Ti-2Al-1.5Mn合金表面纳米管阵列薄膜的光电化学响应特性研究

采用阳极氧化法在20V条件下氧化3h于TC1(Ti-2Al-1.5Mn)合金表面制备了纳米管阵列薄膜。研究了薄膜的表面形貌及结构,着重考察其作为光电极的开路电位和光生电流响应特性。结果表明,该纳米管膜具有高度有序的纳米管阵列结构,平均管径90nm,管长520nm。经过600℃热处理后,该薄膜电极光电响应速度快,光生电子和空穴的复合少,电子的传输效率高。     

SiO2-MTES-CTAB-Al2O3纳米复合薄膜的制备及性能研究

以异丙醇铝和正硅酸乙酯为主要原料,采用溶胶-凝胶分步水解法,通过引入有机硅烷甲基三乙氧基硅烷和表面活性剂十六烷基三甲基溴化氨,并用乙二醇甲醚替换铝溶胶中水作为对比,制备了SiO2-MTES-CTAB-Al2O3纳米复合薄膜.通过FT-IR、可见光透射光谱分析、薄膜表面接触角测量及机械性能测试,研究了化学组成、煅烧温度和有无乙二醇甲醚替换对复合薄膜的影响.结果表明:不用乙二醇甲醚替换效果更好,经400 ℃热处理后不同配比复合薄膜在可见光区的透光率均大于85%,且不影响复合薄膜的疏水性,由于铝氧化物颗粒、十六烷基三甲基溴化氨和甲基三乙氧基硅烷的存在,所制备的纳米复合薄膜的硬度及耐摩擦性能均有较大提高,改善了力学性能,从而获得了具有良好的疏水性、透过率及硬质的SiO2-MTES-CTAB-Al2O3纳米复合薄膜.     

热处理过程对Ag2O-SiO2复合薄膜光学性能的影响

利用溶胶-凝胶法在浮法玻璃上制备了Ag2O-SiO2复合薄膜,通过改变热处理温度和时间得到不同条件下的试样。利用GD751型紫外-可见分光光度计和RF-5301PC型荧光光度计研究了试样的光吸收性能和光致发光性能,并对其发光机理进行初步探讨。在nAg/nSi=0.03的浓度下,探讨热处理温度与时间对Ag2O-SiO2复合薄膜光学性能的影响。在本实验中,当热处理温度为500℃时,复合薄膜的光学性能相对较好。银颗粒的尺寸和化学状态对Ag2O-SiO2复合薄膜的发光性能影响非常大。     

PVA醇解度对热致变导电PVA/AgNO3_薄膜结构和性能的影响

采用不同醇解度的聚乙烯醇(PVA)和硝酸银(AgNO_3)为原料,通过溶液成膜法制备了在固相具有热致变性能的导电PVA/AgNO_3复合薄膜。采用FTIR表征了各种醇解度的PVA与Ag+之间的络合作用。通过TG、SEM、X-射线衍射、X射线能谱(EDS)等方法研究了不同醇解度的PVA/AgNO_3复合薄膜的热性能和热处理后薄膜表面形貌和结构,结果表明:不同醇解度的PVA/AgNO_3复合薄膜在160~200℃均有一明显失重峰;随着醇解度增加,SEM显示热处理后纳米银粒子尺寸减小;实验发现在温度为170~200℃时,醇解度为80%、88%、92%的PVA/AgNO_3复合薄膜其表面电阻率能从300~500 kΩ突然降低到5~20Ω(降低4~5个数量级),而醇解度为97%的PVA/AgNO_3复合薄膜表面电阻率不能发生突变,反而升高。这种具有独特电阻率-温度特性的薄膜在热敏电阻或温度传感器等方面有潜在应用。     

二氧化钛/聚丙烯酸酯纳米复合物的光聚合动力学研究

研究了以Span85/Tween80为表面活性剂的反胶束溶胶-凝胶法光聚合原位合成TiO2/聚丙烯酸酯纳米复合薄膜,考察了影响纳米复合薄膜光聚合反应速率的因素,并用原子力显微镜(AFM)对纳米复合薄膜的表面形态进行了表征。实验结果表明,减少溶水量和钛酸丁酯浓度、增大光引发剂浓度会增大复合薄膜光聚合反应速率和最终转化率。AFM结果表明平均尺寸为25 26nm的无机TiO2粒子均匀分散在有机相基体中,二氧化钛/聚丙烯酸酯复合薄膜的表面粗糙度参数Ra、Rz和Ry分别为1 529～2 263、4 691～16 69nm和10 60～18 97nm,表明所合成的纳米复合薄膜的表面粗糙度低,表面光滑平整,基本达到了纳米器件对表面精度的要求。     

Characterization of antireflective coatings on poly(methyl methacrylate) substrate by different process parameters

The high/low refractive index organic/inorganic antireflective (AR) hybrid polymers were formed using the sol–gel process, in which TiO₂/2‐hydroxyethyl methacrylate (2‐HEMA) (high refractive index hybrid polymer) and SiO₂/2‐HEMA (low refractive index hybrid polymer) two‐layer thin films were formed on a hard coating deposited poly(methyl methacrylate) (HC‐PMMA) substrate by both spin coating and dip coating. The relationship between the process parameters and the optical properties, thickness, porosity, surface morphology, and adhesion was determined. The results show that the reflectance of the two‐layer thin films on HC‐PMMA substrate is less than 0.21% (λ = 550 nm), with good adhesion (5B) and a hardness of up to 4H. In addition, the thickness, porosity, and roughness of the films affect refractive index and the antireflection properties of the AR two‐layered thin film. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Super black and ultrathin amorphous carbon film inspired by anti-reflection architecture in butterfly wing

An ultrathin and super black amorphous carbon (a-C) film has been fabricated by borrowing the inverse V-type anti-reflection nano-architecture from the black wings of butterfly Ornithoptera goliath through vacuum sintering process. The biomimetic a-C film shows good optical absorption (99%) at low reflectance (<1%) in visible light (380–795 nm), which is comparable to the previously fabricated darkest materials, while with a thickness (5 μm) of only 15% of those materials. Experimental results as well as theoretical simulation which is based on finite difference time domain method (FDTD) show that reflection of the fabricated inverse V-type structured a-C film is merely 1/13 of that of the flat surface a-C film, and 1/8 of that of glassy carbon. Complex refractive index of the derived a-C for visible light (380–795 nm) has also been calculated.     

氮化铝薄膜的光学性质

采用直流磁控溅射法在石英衬底上制备了氮化铝(AlN)薄膜.用X射线衍射仪分析了薄膜结构.利用椭圆偏振仪和紫外/可见/近红外分光光度计对AIN薄膜进行了相关光学性能的研究,获得到了薄膜的折射率随波长的色散关系曲线.在波长为250～1 000 nm,薄膜的折射率为1.87～2.20.结合透射光谱图,分析了AIN薄膜的光学性质.结果表明:利用磁控溅射方法可以获得(100)择优取向AIN薄膜;AIN薄膜在200～300 nm远紫外光范围内具有强烈的吸收,在300～1000 nm波长范围内具有良好的透过率.透射光谱图计算得到的薄膜厚度(427nm)与椭圆偏振拟合得到的薄膜厚度(425nm)一致.     

Surface plasmon resonance spectroscopic comparison of spiroxazine monolayer and polymeric thin film

Photochromic dye has recently attracted much interest in optical applications because of its reversible photoswitching properties by light irradiation. To apply those aspects of photochromism to actual photonic devices, the form of the thin film must be favorable to the photochromic molecular system. In this study, a polymeric thin film and self‐assembled monolayer were constructed with a photochromic spiroxazine derivative that is well known for its good fatigue properties. Their photoisomerization properties were characterized through surface plasmon resonance (SPR). As a result of ultraviolet irradiation to these thin films, the SPR angle shift clearly appeared as the optical thickness (Refractive index × Geometrical thickness) change in both of the films. The Fresnel calculation based on measurement results showed that the angle shift of the polymeric thin film mainly corresponded to the change of the refractive index. For the spiroxazine monolayer, the geometrical thickness change caused the resonance angle to shift dominantly. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3459–3465, 2003     

Modified Envelope Method for Obtaining Optical Properties of Weakly Absorbing Thin Films and Its Application to Thin Films of Pb(Zr,Ti)O3 Solid Solutions

A modified envelope method, which includes the consideration of the light intensity loss from the back surface of the substrate, was developed and shown to be a simple and convenient tool for obtaining the optical properties and the thickness of the film by using the transmission spectra alone in the medium and weak absorption regions. In the near-optical band gap region, both the transmission and the reflection spectra were used to calculate the optical constants of the films. This technique was applied to the thin films of PZT solid solutions across the entire composition range. The film thickness derived from the envelope method was cross-checked by a computer simulation method and was found to have an accuracy better than 2%. In addition, the refractive indices were fitted to a simple Sellmeier-type equation for determining the dispersion constants for PZT films. The valid wavelength range of these dispersion relations was from 350 to 2000 nm. The refractive index of the PZT films decreased linearly with increasing zirconium content. On the other hand, the optical band gap energy of the PZT films increased with increasing zirconium content.     

Synthesis and characterization of titanium dioxide optical films by sol–gel processes

The main purpose of this study is to synthesize the front panel of monitor with a high refractive index optical film. Our experiment uses titanium dioxide nanoparticles mixed with methyl methacrylate (MMA), 2‐hydroxyethyl methacrylate (2‐HEMA), and tri(ethylene glycol) dimethacrylate (TEGDMA) of the wet type and economical sol–gel production process. Our product has a superior mechanical, thermal, and optical properties was demonstrated by Fourier transform infrared spectrum (FTIR), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), UV/visible spectrum, and Spectro Ellipsometer. In addition, we found the surface of the two series of thin film with the organic and inorganic high refractive index (TiO₂) mixed materials, has high transmittance for visible light above 90%, refractive index <1.65 and the hardness test 6H. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2271–2280, 2007     

Optical and physical properties of zirconium dioxide reinforced poly(methyl methacrylate) nanocomposite films

The objective of this study was to investigate the fundamental aspects of acrylic resin and zirconia nanoparticle interaction to analyze the optical properties and subsequent changes in refractive index with incremental loading of nanoparticles. Poly(methyl methacrylate) (PMMA) reinforced with zirconia nanoparticles were prepared by dip coating, spin coating and solvent casting techniques. An overall understanding of the polymer nanocomposite film has been achieved using the spectroscopic and morphological studies. The vital aspect of this whole study is to derive a simple yet an efficient nanocomposite film capable of imparting extraordinary optical properties. Within the limitations of this research a very crucial property of the material has been revealed. The RI as well as the optical transparency of the nanocomposite film has been steadily maintained with a significant increase of RI by the magnitude of 0.06 and ~100% light transmittance on incorporation of pure zirconia nanoparticles into PMMA matrix has been achieved. The best technique found was spin coating as it could yield thin films and better transparency and higher refractive index.     

Research on Preparation,Structure and Properties of TiO2/Polythiourethane Hybrid Optical Films with High Refractive Index

Hybrid optical films of TiO₂‐triethoxysilane‐capped polythiourethane (TCPTU) with high refractive indices have been prepared via an in situ sol‐gel method. The high refractive index triethoxysilane‐capped polythiourethane (TCPTU) was synthesized by polyaddition of the triethoxysilane‐modified trimercaptothioethylamine (TMTEA) and 2,2′‐dimercaptoethylsulfide (MES) with 2,4‐tolylene diisocyanate (TDI). The titania content in the hybrid films can be adjusted from 0 to 80 wt.‐% by the feed ratio of titania precursor [Ti(OBu)₄] to polymer (TCPTU). Both FTIR and DSC analyses indicate that there is chemical bonding between the titania domain and the polymer chain. TGA results suggest that the titania of high content was successfully incorporated into polymer matrices and this series of hybrid films have good thermal properties. AFM measurements indicate that in the hybrid films the titania domains are of nanosize scale and the domain size averagely decreases from 60–80 nm to 5–20 nm with increasing content of titania, and the variation of surface roughness for the hybrid films has the same trend. These may be relative to the content of TCPTU and the interaction between titania and polymer (TCPTU). The refractive indices of the hybrid films at 632.8 nm increased from 1 632 to 1 879 as the titania content varied from 0 to 80 wt.‐%.

AFM image of the hybrid film.     

Nanostructured titanium nitride for highly sensitive localized surface plasmon resonance biosensing

Titanium nitride (TiN) as an alternative plasmonic ceramic material with superb properties including high hardness, outstanding corrosion resistance and excellent biocompatibility, has exhibited great potential for optical biochemical sensing applications. By sputtering about 35 nm–50 nm TiN on glass (f-TiN), the surface was found to provide sensing capability toward NaCl solution through the phenomenon of surface plasmon resonance. When the TiN film of about 27 nm–50 nm in thickness was sputtered onto a roughened glass surface (R–TiN), the sensing capability was improved. This was further improved when holes at nanoscale were created in the TiN film of about 19 nm–27 nm in thickness (NH–TiN). The roughened surface and nanohole patterns provided confinement of surface plasmons and significantly improved the sensitivity toward the local refractive index changes. In detail, the calculated refractive index resolution (RIR) of the optimal NH–TiN sensors for NaCl was found to be 9.5 × 10⁻⁸ refractive index unit (RIU), which had outperformed the f-TiN and R–TiN sensors. For biosensing, the optimized NH–TiN sensor was found to be capable to detect both small and large biomolecules, i.e. biotin (molecular weight of 244.3 g/mol) and human IgG (160,000 g/mol), in a label-free manner. Especially, the NH–TiN sensor significantly improved sensitivity in detecting small molecules due to the localized plasmonic confinement of electromagnetic field. Combining with the excellent mechanical and durability properties of TiN, the proposed NH–TiN can be a strong candidate for plasmonic biosensing applications.     

Photoinduced reversible refractive index changes in doped poly(methyl methacrylate) lightguides

Planar polymer lightguides of poly(methyl methacrylate)(PMMA) doped with the azo dye, N,N-dihexyl-4-amino-4′-nitro-azobenzene (DHANA) were fabricated on a suitable glass substrate or on one surface of a regular prism. The absorption of this azo dye is strong in the green spectral region. With the red light of a HeNe laser (633 nm) these polymer films may be used as lightguides. However, in this spectral region, the guided light influences the waveguiding properties of the polymer film, making this combination a possible candidate for an all optical device material. The observed refractive index changes are intensity dependent and the response time is of the order of 100ms.