钒酸基/聚苯胺修饰薄膜的制备及湿敏性能研究

采用交替沉积法制备了钒酸基/聚苯胺薄膜,讨论酸种类和不同层数对薄膜湿敏性能的影响,实验结果表明:钒钛酸/聚苯胺复合膜的湿敏性能优于钒酸/聚苯胺薄膜,双层钒钛酸/聚苯胺薄膜的湿敏性能均优单层,该湿敏薄膜的湿滞为5%RH,灵敏度变化了三个数量级,响应时间为8s,恢复时间为13s,线性度和稳定性均较理想。     

石墨烯/导电聚合物复合防腐蚀材料制备及应用研究进展

石墨烯/导电聚合物复合材料不仅具有石墨烯优异的屏蔽性能和导电聚合物良好的氧化还原特性,还能协同发挥二者的功能,在金属防腐蚀领域有着巨大的应用潜力。本文综述了石墨烯/导电聚合物复合防腐蚀材料的制备方法,包括电化学方法、化学氧化法、分散液混合法和化学气相沉积法（CVD）;并全面总结了石墨烯/导电聚合物复合材料在防腐蚀涂层中的应用及性能。制备的石墨烯/导电聚合物复合材料可以通过电化学方法、溶剂挥发法制成石墨烯/导电聚合物防腐蚀薄膜涂层,还可以混入成膜物树脂中制备树脂复合防护涂层。讨论了石墨烯/导电聚合物在制备过程、薄膜涂层和树脂复合涂层应用中的优势与不足,提出了构建结构可控、综合性能好的复合防腐涂层是石墨烯/导电聚合物复合防腐蚀材料的未来主要发展趋势。     

棒涂法制备石墨烯类透明导电薄膜及表征

以石墨粉为原料,通过改良的Hummers法制备氧化石墨烯,利用Meyer棒通过棒涂法制备氧化石墨烯薄膜,选择氢碘酸还原制备石墨烯透明导电薄膜,用X射线衍射仪、显微共焦激光拉曼光谱仪、傅里叶变换红外光谱仪、场发射环境扫描电子显微镜、四探针测试仪、原子力显微镜对其进行表征。结果表明:石墨粉被有效氧化,大量的含氧官能团被引入分子结构中;当氧化石墨烯溶液质量分数为2%时,所制备的石墨烯透明导电薄膜性能较佳,其方阻为8.38 kΩ/口,透光率(550 nm)为81.3%,薄膜的平均厚度为57.4 nm,扫描电镜图显示其薄膜表面光滑无皱褶。该方法简单易操作,成本低廉,对石墨烯透明导电薄膜的批量制备具有潜在的应用价值。     

聚氨酯/还原氧化石墨烯聚对苯二胺薄膜的制备与性能

采用Hummers法制备氧化石墨烯（GO）,并在其表面原位聚合聚对苯二胺(PPDA),再经水合肼还原得到还原氧化石墨烯聚对苯二胺(RGO-PPDA)复合体,并用其改性热塑性聚氨酯(TPU)薄膜,最终通过溶液涂膜制得TPU/RGO-PPDA复合薄膜。通过傅里叶变换红外光谱仪、X射线衍射仪、扫描电子显微镜、透射电子显微镜、X射线光电子能谱仪对RGO-PPDA纳米复合体进行表征,并利用氧气透过仪、高阻计对TPU/RGO-PPDA复合薄膜的性能进行测试,并与TPU/GO-PPDA复合薄膜性能进行对比。结果表明,GO上原位聚合PPDA,显著改善了GO的亲油性,这有利于GO在氮氮二甲基甲酰胺(DMF)中的分散,进而有利于实现在TPU基体中的均匀分散;当RGO-PPDA含量为0.8 %(质量分数,下同)时,TPU/RGO-PPDA复合薄膜的氧气透过率降低了73.28 %,导电性能提升了8个数量级,表现出良好的阻隔抗静电性能。     

透明超级电容器电极的制备及其电化学性能研究

超级电容器因其充电速度快、使用寿命长、无污染以及免维护等特征,已经受到了越来越多国内外研究者的关注。本文研究了使用氧化铟锡-聚对苯二甲酸乙二醇酯(ITO-PET)导电薄膜和氧化石墨烯制备透明电极的方法。采用电沉积法将氧化石墨烯沉积到ITO-PET透明导电薄膜的表面制备得到电极材料,并研究其性能。     

石墨烯-银纳米线复合透明柔性导电薄膜的制备及性能研究

柔性透明导电薄膜拥有优秀的光学及电学性能,目前应用最广泛的即ITO透明导电薄膜,但由于其缺点显著,限制了未来的发展,使得发展新一代透明导电薄膜成为了当今透明导电领域发展的主流。以聚对苯二甲酸乙二酯(PET)为柔性基底,采用了L-B提拉膜法和喷涂法,分部进行了还原氧化石墨烯(r GO)和银纳米线(Ag NW)复合薄膜的制备,研究了不同制备条件对复合薄膜透明度和导电性能的变化的影响。由于还原氧化石墨烯和银纳米线优秀的导电性以及透光性能,使得其在今后的柔性显示设备的应用中展现出了巨大的应用前景。     

WO_3/氮掺杂石墨烯复合材料的制备及室温气敏研究

以氨水为氮源,采用简便的超声法将氮元素掺杂进石墨烯,通过溶胶-凝胶法制备WO3/氮掺杂石墨烯复合材料,经Raman、XPS、TEM等表征对其进行结构和形貌分析,并在光电流平台上测试其对NO2气体的室温气敏性能。结果表明,对石墨烯进行氮掺杂后形成新的C-N键,石墨烯表面缺陷增加,导电性能提升,WO3/氮掺杂石墨烯复合材料表现出优异的室温气敏特性。     

吡咯基聚电解质材料的湿敏特性

利用Friedel-Crafts反应及氧化聚合,制备了吡咯基聚电解质湿敏元件。研究了羧酸盐种类对元件不同湿度下响应特性的影响,并对其湿敏机理进行了探讨。结果表明：元件同时包含离子与电子两种导电机制。基于P（Py-COONa）材料湿敏元件的特点是具有快的响应速度（吸湿12.5s,脱湿15.2s）,并在低湿下具有较好的导电性,可应用于低湿环境（～0%RH）的检测。     

还原温度对氧化石墨烯的湿度-甲醛交叉敏感性能的影响

以氧化石墨烯溶胶为前体,通过旋涂工艺制备薄膜型气敏元件,在低温80～180℃下进行热处理,获得系列不同还原程度的还原氧化石墨烯气敏元件,采用XRD、AFM、FT-IR、XPS对样品的层结构、薄膜厚度及含氧官能团变化属性进行表征,将气敏薄膜元件在相对湿度为11.3%～93.6%的范围内进行预湿处理,并测定元件对甲醛气氛的敏感性能。结果表明：随热还原处理温度的升高,氧化石墨烯的结构逐渐向类石墨结构转变,含氧官能团逐渐脱失,缺陷增多,薄膜的方块电阻呈数量级地减小,从41 MΩ减小至928 Ω;经不同湿度预处理的气敏元件置于甲醛气氛中产生了水分子与甲醛分子的竞争吸附,从而导致电阻的明显变化;在10^?4甲醛气氛下,未还原或热还原温度较低的气敏元件适用于低、高湿环境下甲醛气氛的气敏测试,最大灵敏度为69.1%,而还原温度适中的元件则适用于中湿环境的甲醛测试,最大灵敏度为80.3%。     

钒钛酸-聚苯胺薄膜电极的制备及电化学性能

以苯胺和自制钒钛酸为原料,ITO导电玻璃为基底,利用一步法和两步法分别制备了钒钛酸-聚苯胺薄膜修饰电极,系统地研究了该复合薄膜的成膜机理和电化学行为。实验结果表明,一步法比两步法制备过程简单,且钒钛酸能逐层固定在聚苯胺薄膜里。该修饰电极不仅保持了钒钛酸的电化学活性和电催化性能,并具有良好的稳定性。两种方法制备的薄膜修饰电极对酸性水溶液中的碘酸钾均具有显著的的电催化还原作用。     

Synthesis and humidity sensitive properties of pyrrole‐based polyelectrolytes

Pyrrole (Py)‐based polyelectrolytes (Py‐PE): P(Py‐COOLi), P(Py‐COONa), and P(Py‐COOK) was synthesized, characterized, and used to prepare thin film resistive humidity sensors. Their humidity sensitive properties have been investigated, and sensing mechanism was presented. The Py‐PE contains PPy as backbone and the side chain bearing carboxylic salt group, which made its sensor exhibited a very wide humidity sensing range of 0–97% relative humidity (RH), high conductivity even at very low humidity, and both ionic and electronic conduction contributed to its conductivity. Among all the Py‐PE, P(Py‐COOK) showed high sensitivity, with the impedance changing of about three orders of magnitude (10³–10⁶ Ω) from 97 to 0% RH, whereas P(Py‐COONa) showed quick response for both absorption (12.5 s) and desorption (15.2 s). Py‐PE prepared is promising for preparation of thin film resistive humidity sensors capable of detecting low humidity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

层层自主装法制备GO杂化多壁微胶囊及其稳定性的影响探究

氧化石墨烯(GO)纳米粒子片层结构可用作Pickering乳液分散剂,芯材离子液体的稳定分散是制备微胶囊的关键,以GO作为Pickering乳液分散剂,并设计以GO为单一壁材制备了自润滑微胶囊,考虑到GO具有优异的耐摩擦性能和良好的热稳定性,再通过层层自主装法,使得壁层之间可以通过静电吸附和氢键作用连接,从而合成多层GO壁自润滑微胶囊。重点研究pH值、油水比、GO的质量浓度对GO的Pickering乳液的影响及GO杂化多壁微胶囊制备的最佳稳定条件。实验证明在pH值为2,油水质量比为5%,GO质量浓度为0.1 mg/L的实验条件下制备的微胶囊最佳。     

Multifunctional polyimide/graphene oxide composites via in situ polymerization

In this article, we detail an effective way to improve electrical, thermal, and gas barrier properties using a simple processing method for polymer composites. Graphene oxide (GO) prepared with graphite using a modified Hummers method was used as a nanofiller for r‐GO/PI composites by in situ polymerization. PI composites with different loadings of GO were prepared by the thermal imidization of polyamic acid (PAA)/GO. This method greatly improved the electrical properties of the r‐GO/PI composites compared with pure PI due to the electrical percolation networks of reduced graphene oxide within the films. The conductivity of r‐GO/PI composites (30:70 w/w) equaled 1.1 × 10¹ S m^?1, roughly 10¹⁴ times that of pure PI and the oxygen transmission rate (OTR, 30:70 w/w) was reduced by about 93%. The Young's modulus of the r‐GO/PI composite film containing 30 wt % GO increased to 4.2 GPa, which was an approximate improvement of 282% compared with pure PI film. The corresponding strength and the elongation at break decreased to 70.0 MPa and 2.2%, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40177.     

Preparation, characterization, and supercritical carbon dioxide foaming of polystyrene/graphene oxide composites

Graphene oxide (GO) was prepared by oxidation of graphite using the Hummers method, and was modified by isocyanate to obtain dispersed GO sheets in dimethylformamide. Polystyrene (PS)/GO composites were prepared by solution blending, and their morphologies and properties were characterized. The addition of GO increased the glass transition temperature of the PS/GO composites. The storage modulus and thermal stability of the composites were also improved compared with PS. Foams of PS and PS/GO composites were prepared by supercritical carbon dioxide foaming. The composite foams exhibited slightly higher cell density and smaller cell size compared with the PS foam, indicating the GO sheets can act as heterogeneous nucleation agents.     

Facile and safe graphene preparation on solution based platform

Graphene has attracted increasing attention because of its interesting properties. In this study, graphene was prepared from graphite by a very simple and easy process. The two-step protocol involves conversion of graphite to graphene oxide (GO) by oxidation, and subsequent reduction of GO to graphene. The structures and properties of the obtained GO and graphene were characterized via X-ray diffraction, and Raman, NMR, UV–vis absorption, and X-ray photoelectron spectroscopic techniques. The morphologies of these products were observed via field emission scanning electron microscopy. The preparation protocol is simple, easy, environmental friendly, i.e., nontoxic, and the yield of graphene is high.     

Preparation and Characterization of hybrid graphene oxide composite and its application in paracetamol microbiosensor

Graphene oxides decorated with Sn(II) (Sn‐GO) were prepared via a redox reaction between graphene oxide (GO) and SnCl₂. GO was reacted Sn²⁺ leading to a homogeneous distribution of Sn on GO. An electrochemical sensor based on the electrocatalytic activity of functionalized graphene oxide for sensitive detection of paracetamol is presented. The electrochemical behaviors of paracetamol on grapheme modified carbon fiber electrodes were investigated by DC potential amperometry. The results showed that the Sn‐GO‐modified electrode exhibited excellent electrocatalytic activity to paracetamol. A redox process of paracetamol at the modified electrode was obtained. Such electrocatalytic behavior of graphene oxide is attributed to its unique physical and chemical properties, e.g., subtle electronic characteristics, attractive π–π interaction, and strong adsorptive capability. This electrochemical sensor shows an excellent performance for detecting paracetamol with a detection limit of 8 µM, a response time of 27 s, and a satisfied recovery. The sensor shows great promise for simple, sensitive, and quantitative detection and screening of paracetamol. We have investigated the composite properties of the self‐assembled electrodes for biological compounds analysis and showed that the Sn‐GO composite biosensor can achieve great sensitivity without significant bio material. The sensor shows great promise for simple, sensitive, and quantitative detection and screening of paracetamol. POLYM. COMPOS., 36:221–228, 2015. © 2014 Society of Plastics Engineers     

Preparation of carbon-based transparent and conductive thin films by pyrolysis of silylated graphite oxides

Thin films of silylated graphite oxide were obtained from a chloroform/cyclohexane dispersion of n-hexadecylamine-intercalated silylated graphite oxide by a casting method at a low temperature. Carbon-based thin films were obtained from the pyrolysis of the resulting films under a reduced pressure at 500 °C or higher temperatures. The resulting samples were well adhered to the substrate because of the presence of silicon containing species as a “glue”. The resistivity decreased with an increase in the film thickness or a decrease in the transparency. Based on the data obtained for the samples prepared from graphite with different particle sizes and graphite oxide with different oxygen contents, the conduction of the electrons within each carbon sheet seemed important for large film thickness and conduction through the boundary seemed important when the film thickness was small. A low sheet resistance of 3.7 kΩ/sq for 80% of transmittance was achieved, when graphite oxide with a lower oxygen content was prepared from graphite with smaller particle sizes and the precursor film was heated at 500 °C. At 900 °C, it further decreased to a value of 700 Ω/sq.     

Layer-by-layer assembly of graphene/polyaniline multilayer films and their application for electrochromic devices

Graphene/polyaniline (PANI) multilayer films were prepared via alternate deposition of negatively charged graphene oxide (GO) and positively charged PANI upon electrostatic interaction, followed by the reduction of their GO components with hydroiodic acid. The thickness of the multilayer film increased linearly with the number of its bilayers and that of each bilayer was measured to be about 3 nm. Cyclic voltammetry studies indicated that these thin composite films were electroactive, and their redox reactions were related to the insertion-extraction of counter ions in PANI layers. Furthermore, the composite films were tested to be promising electrode materials for electrochromic devices even without using the conventional indium tin oxide (ITO) electrodes.     

High thermal conductivity and increased thickness graphene nanosheet films prepared through metal ion-free route

With the miniaturization and integration of electronic devices heat conduction becomes a serious problem. Graphene films catch research's attention because of its excellent thermal performance and graphene oxide (GO) has been used as the most common precursor to prepare graphene films. But mostly film fabricated from GO is thinner than 30 μm and much thicker films are required to meet certain requirements. Also taking GO as raw material has many disadvantages such as the introduction of massive concentrated sulfuric acid and metal ions, huge weight loss in heat treatment and so on. Herein, we propose a new strategy to prepare graphene nanosheet films (GNFs) with a thickness of 100 μm by vacuum filtration of expand graphite through weak oxidation (WEG). Unlike common strategy, WEG without any metal ions introduced instead of GO is chosen as our raw material. The addition of nonionic surfactant and the employment of microfluidization can stabilize WEG dispersion. After graphitization at 2800 °C WEGF is transferred to GNF. The obtained 100 μm-thick film possesses a decent in-plane thermal conductivity (TC) of 760 W/mk and electrical conductivity (EC) of 5.2×10⁵ S/m. Thick films with high TC can guarantee passing more heat flux and fill in larger gaps inside devices.