Characterization of N-cyclohexylmethacrylamide LB thin films for room temperature vapor sensor application

This study reports the synthesis, characterization and gas sensing applications of N-cyclohexylmethacrylamide (NCMA) monomer material using FT-IR, ¹H and ¹³C NMR, UV-visible spectroscopy, Quartz Crystal Microbalance (QCM) and Langmuir-Blodgett (LB) thin film deposition techniques. The thin film deposition conditions of NCMA monomer material, which are prepared by LB film technique, are characterized by UV-visible spectroscopy and QCM system. The sensing behaviors of the LB film with respect to volatile organic compounds (VOCs) at room temperature are investigated. Surface pressure change as a function of surface area of NCMA molecule at the water surface shows a well-organized and stable monolayer at 18 mN m^?1 surface pressure value for LB film deposition. Transfer ratio values are found to be ≥ 0.94 for quartz glass and ≥ 0.93 for quartz crystal substrate. The typical frequency shift per layer is obtained 20.10 Hz/layer and the deposited mass onto a quartz crystal is calculated as 824.62 ng/layer. The sensing responses of the LB films against chloroform, dichloromethane, acetone, toluene, benzene and ethanol are measured by QCM system. The sensitivities of the NCMA LB film sensor are determined between 0.085 and 0.029 Hz ppm^?1. Sensitivities with detection limits are between 35.29 and 100.33 ppm against organic vapors. These results can be concluded that the monomer LB film sample is found to be significantly more sensitive to chloroform and dichloromethane vapors than others organic vapors used in this work. This material may find potential applications in the development of room temperature organic vapor sensing.     

Precise Control of Metal Oxide Thin Films Deposition in Magnetron Sputtering Plasmas for High Performance Sensing Devices Fabrication

Magnetron sputtering deposition is a widely used technique to deposit thin film precisely at nanoscale level. During the deposition of metal oxide thin films, reactive oxygen gas is introduced into the deposition chamber. Pure metal and metal oxide materials can be used as sputter target, although the simplest way is by using a pure metal target. In such reactive process, the effect of target poisoning significantly influence the deposition process and the growth mechanisms of metal oxide thin films became very complex. In general, external parameters such as discharge power, working pressure, reactive gases ratio and substrate temperature are used to optimize the properties of deposited thin films. Then, ex-situ analyses such as scanning electron microscope and X-ray diffraction analysis are performed to obtain the optimized parameter. Sample depositions and ex-situ analyses consume time to achieve the goal through try and error. In this article, in-situ plasma diagnostics are reviewed focusing on an optical emission spectroscopy to precisely control and investigate the sputter target poisoning effect during the deposition of metal oxide thin films. The emission of atomic lines from several metal and oxygen atoms were used to discuss the deposition mechanisms and their correlation with the deposited thin films was observed. Finally, the deposited metal oxide thin films were proposed and tested for several applications such as gas sensor and frequency selective surface glass.     

基于p-6P异质诱导生长酞菁铜薄膜的NO2传感器

为实现室温下低浓度NO₂气体检测,制作了p-六联苯(p-6P)诱导层的酞菁铜有机薄膜传感器。利用原子力显微镜(AFM)研究了不同沉积速率下p-6P薄膜的生长规律,慢速沉积提供足够的分子扩散时间,利于薄膜横向生长,形成高度低、尺寸大的晶畴。在p-6P薄膜上生长了酞菁铜薄膜,可以清晰看到晶畴上酞菁铜薄膜的有序排列。利用X射线衍射(XRD)仪,阐明了p-6P对酞菁铜薄膜具有很好的诱导效应。通过对比不同沉积速率p-6P薄膜诱导的酞菁铜传感器性能,发现慢速沉积诱导层的酞菁铜器件有高的响应强度和低的回复时间。异质诱导生长的酞菁铜传感器响应强度是直接生长在二氧化硅上的酞菁铜传感器的2倍,回复时间是3.2 min,对浓度为1.0 × 10^-5的NO₂气体灵敏。     

碳纳米管薄膜晶体管中的接触电阻效应

利用不同功函数的金属作为接触电极,研究了网络状碳纳米管薄膜晶体管(CNT-TFT)的接触电阻效应。研究表明金属Pd与碳纳米管薄膜形成良好的欧姆接触, Au则形成近欧姆接触,这两种接触的器件的开态电流和迁移率较高。Ti和Al都与碳纳米管薄膜形成肖特基接触,且Al接触比Ti接触的势垒更高,接触电阻也更大,相应器件的开态电流和迁移率都较低。该结果表明对于CNT-TFT仍然可以通过接触来调控器件的性能,这对CNT-TFT的实用化进程具有重要的促进作用。     

颗粒膜的结构及对乳状液稳定性的影响机制

以颗粒膜为基础的乳液因广泛应用于油田、造纸、食品、化妆品、医药等领域而备受关注。本文归纳了在油水界面形成颗粒膜的颗粒密度、粒径及润湿性等特征,并阐述了颗粒在界面吸附扩散的行为。重点从颗粒垂直于界面的分配及方向,颗粒在界面内的排列及进一步形成的空间结构综述颗粒膜结构。总结了颗粒在界面的状态及颗粒膜结构的影响因素,并从能量及力学角度进行分析。颗粒膜对乳状液稳定性影响机制主要体现在颗粒膜的结构及界面黏弹性：颗粒膜的结构阻隔液滴之间的碰撞聚并,这是乳状液稳定的基础;同时,颗粒膜通过改变界面黏弹性使得液滴在运动、碰撞、絮凝时不会轻易崩溃,从而强化了乳状液的稳定性。固体颗粒为乳化剂形成颗粒膜稳定乳状液的机制探究为稳定乳状液制备以及乳状液的破乳提供理论依据,具有现实意义。最后,本文就颗粒膜稳定乳状液的机制研究展望了其未来发展方向及可能的解决途径。     

Protection of Li metal anode by surface-coating of PVDF thin film to enhance the cycling performance of Li batteries

The PVDF thin film on the surface of the lithium metal can highly suppress the lithium dendrites.     

Synthesis of well‐defined block copolymer composed of flexible amphiphilic poly(ethylene glycol) and hydrophobic liquid crystalline segments by living coordination polymerization of allene derivatives and its application to thin film with perpendicularly oriented cylindrical nanostructure

A block copolymer composed of a flexible polar poly(ethylene glycol) (PEG) and a less polar liquid crystalline poly(allene) segments is prepared by the living coordination polymerization of an allene derivative possessing trans‐azobenzene‐containing mesogenic substituent by the use of a π‐allylnickel macroinitiator bearing PEG segment. The thin film of the block copolymer is prepared by the spin coating of its solution onto mica or silicon wafer which proves to possess perpendicularly oriented nanocylindrical microphase separated structures as supported by the differential calorimetric, polarized optical microscopic, grazing‐incidence small‐angle X‐ray scattering, transmission electron microscope, and atomic force microscope measurements.     

智能蜂窝状有序多孔薄膜：体系构建、响应性能及应用探索

蜂窝状有序多孔膜是一种典型的具有微、纳米尺寸的图案化高分子薄膜材料,在超疏水表面、光电材料、组织工程、生物医学、传感器等领域都具有良好的应用前景。表面形貌或性质具有可逆刺激响应特性的智能型多孔膜不仅拥有常规多孔膜的性能,而且还拥有独特的开-关功能,因此受到广泛关注。本文回顾了智能有序多孔膜近年的研究进展,重点对其体系构建、响应方式、机理、性能和相关应用进行了归纳与分析,评述了不同刺激响应多孔膜的特点及优劣势,探讨了智能多孔膜的优化设计及提高响应性能等问题,指出了目前面临的挑战,并展望了未来的发展方向。     

Details of surface features in aromatic polyamide reverse osmosis membranes characterized by scanning electron and atomic force microscopy

In the present article, some new events on the surface morphology of the aromatic polyamide thin‐film‐composite (TFC) membranes were demonstrated in conjunction with their inherent chemical nature. In addition, the detailed, quantitative understanding of the microscopic surface features was shown to be essential in controlling the water permeability and eventually developing the high performance membranes. The surface roughness and the surface area were mainly affected by the existence or nonexistence of the crosslinking and/or the free amide groups not pertinent to the formation of the hydrogen bonding, which in turn contributed to the water permeability. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1429–1440, 1999     

Preparation,Characterization of Ternary Europium Complex-Doped Thin Sol-Gel Hybrid Film by Fluorescence Spectroscopy

ernary europium complex with dibenzoylmethane(DBM), 1,10-phenanthroline(phen) was in-situ syn thesized in thin SiO₂/polyvinyl butyral(PVB) hybrid films by a two-step sol-gel process, characterized by means of fluorescence spectroscopy. The luminescence spectra, fluorescence lifetimes, photostability were all investigated. The results showed that the hybrid films exhibited the characteristic emission bands of the central rare earth Eu³⁺. In addition, Eu³⁺ presented longer fluorescence lifetime than in an ethanol solution, the complex had a higher photostability in the hybrid film than in the PVB film containing the corresponding pure complex.