Gas adsorption gates based on ultrathin composite polymer films

High surface area alumina coatings were prepared on surface acoustic wave (SAW) mass balances. These coatings were fabricated by anodic etching of evaporated aluminum films. The coatings consisted of roughly collinear pores penetrating through the monolithic alumina film. The nanoporous (NP) coatings were characterized by scanning electron microscopy, and the pore number density and diameter were found to be (3.8 +/- 0.5) x 10(3) pores/microm2 and 6.8 +/- 4.8 nm, respectively. The mass of volatile organic compounds that adsorbed onto naked and chemically modified NP alumina coatings was measured using SAW mass balances and compared to the mass absorbed onto SAW devices having planar aluminum coatings. Thirty-four times more heptane adsorbed to the naked NP coating than to the planar coating. The mass loading response was also measured after modification with organic thin films (3-12 nm thick) that spanned the pores of the NP coating. These organic thin films were composed of sixth-generation, amine-terminated poly(amido amine) dendrimers and poly(maleic anhydride)-c-poly(methyl vinyl ether) (Gantrez). The key result of this study is that these organic thin films modulate adsorption of VOCs onto the pore walls of the NP alumina. Specifically, a single 3-nm-thick monolayer of the dendrimer reduces permeability of the VOCs by approximately 17%, whereas a 12-nm-thick G6-NH2/Gantrez composite reduces permeability by 100%. Thus, the polymer composite acts as a nonselective gate that controls access of VOCs to the underlying surface area of the pores.     

TiO2与聚合物复合薄膜的离子自组装制备及表征

在常温下,以钛酸丁酯[(C4H9O)4Ti]和聚四苯乙烯磺酸钠(PSS)作为前驱物在普通载玻片上用离子自组装法制备了TiO2纳米粒子/PSS复合薄膜,复合薄膜的透过率随镀膜次数或薄膜厚度的增加而呈现周期性变化。透射电镜(TEM)测试结果表明,TiO2呈板钛矿晶体结构,薄膜连续而均匀,TiO2的平均粒径是3.6nm。光电子能谱仪(XPS)测试结果显示,薄膜中含有Ti、O、C元素,载玻片表面完全被TiO2纳米复合薄膜所覆盖。     

FeS2/TiO2复合薄膜光电性能

采用溶液浸渍法在ITO导电玻璃表面的多孔TiO2薄膜上沉积了FeS2薄膜.使用Fe2O3粉末保护裸露在外的ITO导电膜在硫气氛中热处理后,制得了FeS2/TiO2复合薄膜.应用B531/H数显测厚指示表、数字式四探针测试仪、XJCM-8太阳电池测试仪等研究了FeS2/TiO2复合薄膜的厚度、ITO导电玻璃的电阻率以及FeS2/TiO2复合薄膜的光电性能.结果表明：此方法制得的FeS2/TiO2复合薄膜具有良好的光电性能;且ITO导电膜的电阻率变化较小.因而适宜制备色素增感太阳能电池（DSSC）.     

叠层式TiO2/SnO2复合纳米薄膜制备及其光电性能研究

采用溶胶-凝胶法在不同基体表面制备了叠层式TiO2/SnO2复合纳米薄膜.用扫描电子显微镜(SEM)、X射线衍射(XRD)对复合薄膜表面形貌和晶体结构进行表征.采用紫外-可见吸收光谱法和电化学方法来研究复合薄膜光学与光电化学性能特征.结果表明,所制备的叠层式TiO2/SnO2复合纳米薄膜表面连续、均匀、致密;XRD分析表明纳米TiO2为锐钛矿型结构,SnO2为金红石型结构;紫外-可见吸收光谱测试表明叠层式TiO2/SnO2复合纳米薄膜较纯TiO2薄膜的吸收范围拓宽;稳定电位随时间变化曲线(OCP-t)结果表明,叠层式TiO2/SnO2复合纳米薄膜光照下其光电化学性能高于纯TiO2薄膜;同时,光照后叠层式TiO2/SnO2复合纳米薄膜能有效储存TiO2先生电荷,延续对不锈钢基体的光生阴极保护性能.经比较,叠加3层SnO2的TiO2/3SnO2复合纳米薄膜改善光电性能最佳.     

Preparation and characterization of nanocrystalline porous TiO2/WO3 composite thin films

TiO₂ materials possessing not only photocatalytic but also electrochromic properties have attracted many research and development interests. Though WO₃ exhibits excellent electrochromic properties, the much higher cost and water-sensitivity of WO₃ as compared with the TiO₂ may restrict the practical application of WO₃ materials. In the present study, the feasibility of preparing nanocrystalline porous TiO₂/WO₃ composite thin films was investigated.Precursors of sols TiO₂ and/or WO₃ and polystyrene microspheres were used to prepare nanocrystalline pure TiO₂, WO₃, and composite TiO₂/WO₃ thin films by spin coating. The spin-coated thin films were amorphous and, after heat treating at a temperature of 500 °C, nanocrystalline TiO₂, TiO₂/WO₃, and WO₃ thin films with or without pores were prepared successfully. The heat-treated thin films were colorless and coloration-bleaching phenomena can be observed during cyclic voltammetry tests. The heat-treated thin films exhibited good reversible electrochromic behavior while the porous TiO₂/WO₃ composite film exhibited improved electrochromic properties.     

Photocatalytic degradation of formaldehyde by nanostructured TiO2 composite films

Interest in the photocatalytic oxidation of formaldehyde from contaminated wastewater is growing rapidly. The photocatalytic activity of the nanocrystalline Fe³⁺/F^? co-doped TiO₂–SiO₂ composite film for the degradation of formaldehyde solution under visible light was discussed in this study. The films were characterised by field emission scanning electron microscopy (FE-SEM) equipped with energy-dispersive spectroscopy, X-ray diffraction (XRD), BET surface area, UV–Vis absorption spectroscopy, and photoluminescence spectroscopy. The FE-SEM results revealed that the Fe³⁺/F^? co-doped TiO₂–SiO₂ film was composed of uniform round-like nanoparticles or aggregates with the size range of 5–10 nm. The XRD results indicated that only the anatase phase was observed in the film. Compared with a pure TiO₂ film and a singly modified TiO₂ film, the Fe³⁺/F^? co-doped TiO₂–SiO₂ composite film showed the best photocatalytic properties due to its strong visible light adsorption and diminished electrons-holes recombination.     

Synthesis of TiO2-doped SiO2 composite films and its applications

The TiO₂-doped SiO₂ composite films were prepared by two-step sol-gel method and then it was applied in the degradation of methylene red (MR) as photocatalysts. In XRD, FT-IR, and TEM investigations of these TiO₂-doped SiO₂ composite films, the titanium oxide species are highly dispersed in the SiO₂ matrixes and exist in a tetrahedral form. And special attention has been focused on the relationship between the local structure of the titanium oxide species in the TiO₂-doped SiO₂ composite films and the photocatalytic reactivity in order to provide vital information for the design and application of such highly efficient photocatalytic systems in the degradation of toxic compounds diluted in a liquid phase.     

聚苯胺/聚合物透明导电复合膜研究进展

论述了聚苯胺/聚合物透明导电复合膜的制备及性能.原位聚合法、掺杂聚苯胺旋转涂膜法和机械共混浇铸法均可制备透明导电复合膜.所得复合膜具有良好的透明性、导电性、环境稳定性及耐疲劳性能.     

Photoactive TiO2/CuxO composite films for photocatalytic degradation of methylene blue pollutant molecules

Applying photocatalysts for utilizing solar energy is attractive because of its clean and limitless characteristics, but they have giant obstacles such as wide bandgaps, photocorrosion, and rapid charge recombinations to overcome for applications. In this study, the TiO₂/Cu_xO composite films are investigated as photoactive materials for the photodegradation ofmethylene blue (MB) pollutant molecules under standard sun light illumination. The TiO₂ layer is firstly fabricated on the FTO substrate by a doctor blade method, and then the second copper component is introduced by a spin-coating. Then, the composite films are thermally sintered to form cuprous and cupric oxides. This additional copper oxide phases plays a crucial role in achieving high photodegradation performance of MB under light irradiation. The best MB photodegradability from the TiO₂/Cu_xO composite films was achieved with the 3.6 wt% Cu_xO content case, and it is probably due to the effective charge separations with reduced recombinations in the copper oxide phases by the Z-scheme band arrangements between Cu₂O and CuO components. The composite films were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–visible spectroscopy for the film surface and cross-sectional morphology, crystalline structure, atomic binding energy, and light absorbance, respectively.     

玻璃固载TiO2/纳米纤维素复合薄膜的制备及其光催化性能

将微晶纤维素溶解于NaOH-尿素的低温溶液中形成纤维素溶液,在水浴中再生形成纳米纤维素溶液.然后将纳米纤维素溶液与TiO2(P25)混合,并添加少量的钛酸正丁酯作为交联剂形成复合溶液.将制备得到的复合溶液通过流延法固载到玻璃片表面形成玻璃固载的TiO2/纳米纤维素复合膜.通过SEM、XRD表征了复合膜的形貌与结构.将玻璃固载的TiO2/纳米纤维素复合膜在紫外光下进行光催化降解甲基橙(MO)以评估复合膜的光催化性能,研究了纳米TiO2含量对复合膜光催化性能的影响,复合膜的重复使用性能以及光降解的动力学过程.结果表明:复合膜对MO的光催化降解能力可达90％以上,与纯TiO2粉末相当,并重复使用3次光催化性能基本保持不变.复合膜对甲基橙的降解动力学符合一级动力学特征.当纳米TiO2相对于纤维素的质量分数为33.3％时,光催化活性最高,动力学速率常数为0.035min-1.     

纳米TiO2／Al2O3复合薄膜光催化特性研究

以电化学方法合成的Al2O3多孔膜为基体，采用交流电沉积的方法在膜孔中沉积纳米TiO2，制备出纳米TiO2／Al2O3复合薄膜。对TiO2／Al2O3复合薄膜的形貌、结构和组成进行了表征；对TiO2／Al2O3复合薄膜光催化甲基橙溶液进行了研究。结果表明Al2O3／TiO2复合薄膜呈现出较好的光催化活性，电沉积TiO2的时间、热处理温度、选择不同光源照射均对TiO2／Al2O3复合薄膜光催化活性有一定的影响。     

纳米TiO2/SiO2复合涂层修饰玻璃的抗菌功能研究

采用溶胶凝胶法在室温下制备了均匀的纳米二氧化硅和二氧化钛复合薄膜,研究了经不同温度处理、不同TiO2/SiO2 配比的薄膜修饰后的玻璃表面的抗菌性能。用SEM表征了复合薄膜的表面形貌及不同温度处理对颗粒大小的影响, 并利用XRD检测此复合粉体的晶型。研究结果表明,薄膜中的二氧化钛主要以锐钛矿晶型存在,颗粒大小在15~40nm范围内,二氧化硅是非晶的无定型体。实验表明,此薄膜能高效快速地杀死细菌。其抑菌能力与薄膜的热处理温度、纳米SiO2 和TiO 的比率等因素有关。100~500℃热处理后的薄膜经1h自然光照的抑菌率都在90%以上。     

TiO_2-海藻酸钙复合膜的表征、对染料的光催化降解及TiO_2回收

为了解决TiO2纳米粒子难分离,负载的催化剂难回收等问题,首先,将TiO2与海藻酸钠充分混合制成铸膜液,在玻璃板上刮膜,经钙离子交联制备了TiO2-海藻酸钙(T-CA)复合膜。然后,对T-CA复合膜进行了SEM和XRD表征,并研究了T-CA复合膜对染料的光催化降解性能。最后,将T-CA复合膜从染料降解液中取出,浸泡在柠檬酸钠水溶液中,柠檬酸根对钙离子的结合力较强,可使海藻酸盐水凝胶溶解,离心分离TiO2纳米粒子并清洗干燥后,得到了回收TiO2;利用SEM、TEM、FTIR和XRD对回收TiO2进行了表征。结果表明:T-CA复合膜对甲基橙的光催化降解率可达82.37%。回收TiO2与初始的TiO2几乎完全一样,可重新使用且催化能力不变。该方法是一种绿色环保、方便快速的从载体中回收TiO2纳米粒子的方法。     

Dielectric polymer matrix composite films of CNT coated with anatase TiO2

This study presents the fabrication method and the dielectric property of polymer matrix composite films of carbon nanotube (CNT) coated with TiO₂. The TiO₂ was coated with sol-gel method using titanium (IV) butoxide (TNBT), HO₂ and benzyl-alcohol as the surfactant. The configuration of CNT-TiO₂ hybrid was observed with the field emission scanning electron microscope images. The coated TiO₂ was thermally treated and transformed into the anatase structure to enhance the mechanical strength and get the high insulating property. The anatase structure was proved from the diffraction angles of XRD. The CNT-TiO₂ hybrid was mixed with the epoxy resin using 3-roll-mil and casted into the films using film casting method. The structure of CNT-TiO₂ hybrid was ascertained to be maintained against the high shear stress during the mixing and casting processes. The dielectric property of the composite films was measured following IPC-TM-6550. The dielectric property at 1 GHz of the composite film of 5 wt.% CNT is about 10 and the loss tangent at 1 GHz is about 0.06.     

Strain-dependent electrical resistance of multi-walled carbon nanotube/polymer composite films

The strain-dependent electrical resistance characteristics of multi-walled carbon nanotube (MWCNT)/polymer composite films were investigated. In this research, polyethylene oxide (PEO) is used as the polymer matrix. Two representative volume fractions of MWCNT/PEO composite films were selected: 0.56?vol% (near the percolation threshold) and 1.44?vol% (away?from the percolation threshold) of MWCNT. An experimental setup which can measure electrical resistance and strain simultaneously and continuously has been developed. Unique and repeatable relationships in resistance versus strain were obtained for multiple specimens with different volume fractions of MWCNT. The overall pattern of electrical resistance change versus strain for the specimens tested consists of linear and nonlinear regions. A resistance change model to describe the combination of linear and nonlinear modes of electrical resistance change as a function of strain is suggested. The unique characteristics in electrical resistance change for different volume fractions imply that MWCNT/PEO composite films can be used as tunable strain sensors and for application into embedded sensor systems in structures.     

低红外发射率TiO2/AgxCU1-x/Ti/TiO2纳米多层膜

利用磁控溅射制备了银含量在100％至80％之间的单层银铜合金薄膜和TiO2／AgxCu-1x／Ti／TiO2：纳米四层膜。利用x射线衍射、扫描电子显微镜、扫描俄歇微探针,分光光度计、红外发射率测量仪对样品进行表征,研究了单层金属膜和多层膜的光学、电学性质随着银含量的变化以及热处理前后薄膜性能的变化。结果表明：相同厚度的合金膜,随着Ag含量的降低,导电性能下降,Ag含量低于80％的合金已不适合作为多层膜的金属层;1500C大气下热处理30min,纯银薄膜性质发生明显变化,明视透过率下降10％,方块电阻由2．5W／口增加至18W／□,红外发射率由0．17增加到0．69。AgCu合金薄膜性质未发生明显变化。方块电阻相近的TiO2／AgxCu1-x／Ti／TiO2纳米多层膜,经250℃大气下热处理40min后,TiO2／Ag／Ti／TiO2和TiO2／Ag80Cu20／Ti／TiO2纳米多层膜的性质变化较小,热稳定性较好,其余的多层膜性质发生较大变化,红外发射率显著增加。     

Ferroelectricity of ultrathin ferroelectric Langmuir-Blodgett polymer films on conductive LaNiO3 electrodes

LaNiO₃ (LNO) films with a surface roughness rms of 0.384 nm and a sheet resistance of about 200 Ω were prepared on SrTiO₃ and Si/SiO₂ substrates respectively by rf magnetron sputtering technique. The surface of LNO on Si/SiO₂ substrate is smoother than that on SrTiO₃ substrate. A nominal 2-monolayer (ML) poly(vinylidenefluoride-trifluoroethylene) film with a thickness of about 3 nm was deposited on LNO coated Si/SiO₂ substrate by Langmuir-Blodgett (LB) technology. Piezoresponse force microscopy (PFM) measurements show that the LB films demonstrate an obvious feature of polarization switching and good voltage durability. The results suggest that the ultrathin polymer films may be utilized to explore ferroelectric tunnel junctions.     

Natural superhydrophilicity of sol–gel derived SiO2–TiO2 composite films

Sol–gel SiO₂–TiO₂ mixed films have been deposited from a polymeric SiO₂ solution and either a polymeric TiO₂ mother solution (MS) or a derived TiO₂ crystalline suspension (CS). The chemical and structural compositions of MS and CS mixed films heat-treated at 110 or 500 °C have been investigated by Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Water contact angle measurements show that TiO₂ rich MS films exhibit photo-induced superhydrophilicity, but cannot maintain a zero contact angle in the absence of UV light. In contrast, CS mixed films exhibit a natural and persistent superhydrophilicity for a large range of compositions. Superhydrophilic properties are analyzed in terms of enhanced acidity at the SiO₂–TiO₂ interfaces and discussed with respect to the chemical and structural composition of MS and CS films.