基于聚硫堇/过氧化氢光电化学敏感界面的胆碱传感器

将胆碱氧化酶固定在具有光电活性的聚硫堇光透电极的表面,利用壳聚糖和戊二醛键合胆碱氧化酶制备了光致电化学胆碱传感器.此传感器基于同时具有光敏和电子受体功能的聚硫堇光电界面,能与胆碱氧化酶催化胆碱反应产生的电子供体(H2O2)发生光致电化学反应的原理,实现了对胆碱的检测.探讨了传感器的光致电化学响应机理、偏压、光强及电解质...     

镍修饰WO3膜光电化学氧化水的研究

在强碱性溶液中低电压低电流条件下在W基底上经阳极氧化得到致密WO3层,而后在酸性条件下在WO3表面经光辅助电化学还原沉积镍,所获得的复合电极具有优异的光电化学氧化水的活性和稳定性.SEM,EDX,XPS和TEM等表征表明复合电极中具有体心立方结构的W基底经阳极氧化形成了具有单斜结构的WO3层,表面修饰的镍物种以Ni(OH)2形式存在.光电化学实验表明WO3层对可见光具有良好的光响应,表面修饰镍后,光电氧化水的起始电位显著降低,电极的稳定性也得以提高.     

基于静态呼吸图技术的图案化方法

对呼吸图技术制备二维有序多孔结构的研究进展进行了综合评述, 并重点介绍了本课题组发展的静态呼吸图技术. 利用静态呼吸图法, 可制备高度有序的聚合物、聚合物/无机物微孔膜. 这些有序的结构可以直接应用于光掩膜. 进一步, 多孔聚合物膜可以被紫外光交联和改性. 表面改性的多孔聚合物膜可以用于细胞支架. 而交联的聚合物/无机物前驱体微孔膜可以用来制备无机纳米材料阵列. 结果表明, 静态呼吸图技术是一种简单、高效的对聚合物、聚合物/无机物薄膜进行图案化的通用方法,并展示了图案化薄膜广阔的功能化前景.     

金表面偶氮苯自组装膜的光电化学响应

金表面偶氮苯自组装膜的光电化学响应王永强，王健，于化忠，蔡生民，刘忠范（北京大学化学与分子工程学院智能材料研究中心，北京，１００８７１）关键词偶氮苯，自组装膜，光致异构化，电化学偶氮苯基团特征的光致异构化及电化学响应在分子开关器件和超高密度信息存储等...     

偶氮聚合物表面起伏光栅研究进展:光刻写、软印刷复制及应用

偶氮聚合物光致表面起伏光栅研究涉及一系列光和聚合物相互作用的基本科学问题,是近年来国内外研究的热点.将软刻为代表的微加工技术和偶氮表面起伏光栅光刻方法相结合,为表面起伏光栅的制备和应用开辟了新的途径.本文综述偶氮化合物表面起伏光栅光刻和软印刷复制等方面的最新研究进展,并介绍功能性光栅结构和器件在太阳能电池、液晶定向层及...     

等离子体聚合法修饰半导体光电极的研究——聚丙烯腈/n-GaAs,n-GaP电极

用导电聚合物修饰光电化学体系中的半导体电极,对于抑制电极的光腐蚀、改善电极特性及赋予其催化功能有明显的效果.在制备聚合物薄膜的几种方法中,等离子体聚合可得到高度交联、均匀、化学稳定性好的超薄膜,且成膜工序简单,已引起重视并取得初步应用。等离子体聚合法修饰导体电极国内外均有报道,但在修饰半导体电极方面的研究甚少。本文探讨了用这种方法在n-GaAs、n-GaP电极上制备聚丙烯腈(PAN)薄膜,并进行     

光响应性微凝胶的分子设计和智能材料构筑

微凝胶能够在外界刺激下改变自身尺寸,是一类重要的智能材料构筑基元。光刺激具有可远程控制、能快速切换等特点,在刺激响应性材料的设计中受到了广泛关注。将光刺激响应性基元引入到微凝胶体系,可以得到一系列具有重要应用前景的智能材料。本文综述了近年来光响应微凝胶的研究进展,总结了赋予微凝胶光响应性的四种分子设计,包括光致异构化型、光致生热型、光致(解)交联型、光致生酸型;介绍了光响应微凝胶在调光材料、药物控释、信息显示和自修复凝胶等领域的应用;展望了该领域的研究方向、发展和应用前景。     

CdS超微粒子薄膜电极的光电化学特性

采用电化学方法制备了含不同粒度的ＣｄＳ超微粒子薄膜电极，应用表面光电压谱和光电化学技术对电极的光电化学特性进行了研究。结果表明，这些电极具有明显的量子限域效应，同体相材料相经，ＣｄＳ超微粒子萍奄极显示出较高的光电响应，说明该薄膜电极具有独特的光电压和电荷传输机理。     

刚果红交联聚乙烯醇薄膜／K^＋交换玻璃光波导检测氯化氢气体

用环氧氯丙烷为交联剂合成了刚果红(CR)交联聚乙烯醇(PVA)CR-PVA敏感试剂.用匀胶机将其做成薄膜固定在钾离子交换玻璃光波导表面,研制出一种光波导氯化氢气体传感器.CR-PVA薄膜碱式结构的最大吸收波长在600 nm以下,对波长为632.8 nm的激光吸收很弱;薄膜与酸性气体发生反应后强烈吸收波长在632.8 nm附近的导波或消失波;检测输出光强度的变化,即能够测出酸性气体浓度.测试结果表明,本传感器对低浓度HCl气体有快速响应,且对1.6～192 mg/m3范围内有良好的线性响应;SO2、NO2气体的浓度大于18000 mg/m3时才有响应,而对于高、低浓度H2S气体均无响应.     

射频磁控溅射制备纳米TiO2薄膜的光电化学行为

在室温下采用射频磁控溅射法制备了纳米晶粒的TiO2薄膜,用循环伏安法研究了ITO/TiO2薄膜电极的光电化学行为,并测量了相应TiO2薄膜的亲水性与光催化能力.结果表明,在室温下制备的TiO2薄膜为无定形结构,当退火温度超过400 ℃时转化为锐钛矿结构.在400 ℃下退火的TiO2薄膜具有良好的亲水性和光催化能力. TiO2薄膜电极用254 nm的紫外光照射一定时间后会产生新的氧化峰,且随着光照时间的增加,峰电流也增加.初步认为用紫外光照射一定时间后, TiO2薄膜的循环伏安图的氧化峰属于光生的Ti3＋,而光致亲水性可能与Ti3＋的生成有关.     

Photo-responsive behavior of a monolayer composed of an azobenzene containing polypeptide in the main chain

A photoresponsive polypeptide, two -helical poly(-methyl L-glutamate)s joined with an azobenzene (MAzoM,Mn=11000), have been prepared. Monolayers of the polypeptide were formed at air-water interface and the photoresponsive behavior of the monolayer obtained was investigated. A trans to cis photo-isomerization of the azobenzene moiety in the main chain of MAzoM induced by UV light irradiation resulted in a bending structure formation in the main chain of the polypeptide via photo-induced changes in the geometry of the azobenzene chromophore. As a result, the limiting area per molecule of the MAzoM monolayer was decreased. Based on the degree of the decrease in the limiting area per molecule, it was estimated that the bending angle between the two -helical rods of MAzoM molecule under UV light irradiation was ca. 140°. The photo-responsive behavior of the MAzoM monolayer was reversible and consisted along with the photo-isomerization of azobenzene moiety.     

Azobenzene Based Photo-responsive Mechanical Actuator Fabricated by Intermolecular H-bond Interaction

Photo-responsive mechanical actuator is a class of stimuli-responsive materials transferring light to mechanical energy through macroscopic transformation. To fabricate photo-responsive mechanical actuator, soft polymeric materials crosslinked with functional bridging structures are desired. Supramolecular interaction is a relatively common way to fabricate crosslinked materials due to its excellent self-assembly performance. And azobenzene and derivatives are ideal candidates of photo-responsive materials because of the unique photo-induced trans-cis isomerization. Here, a new kind of crosslinked materials based on supramolecular interaction between 4,4'-dihydroxyazobenzene and chitosan is reported. Under 355 nm irradiation, the macroscopic bending of polymeric materials occurs rapidly due to the photo-isomerization of 4,4'-dihydroxyazobenzene. Meanwhile, the photo-responsive mechanical actuator can also lift weight which is up to 200 times that of the actuator itself, and convert energy from light to mechanical work efficiently. This report suggests a new kind of photo-responsive actuator based on supramolecular interaction and may be helpful to contribute a theoretical basis to the design and synthesis of photo-responsive mechanical actuator suitable for large-scale manufacturing industrialization in future.     

A Luminescent Dicyanodistyrylbenzene-based Liquid Crystal Polymer Network for Photochemically Patterned Photonic Composite Film

A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network (LCN)was fabricated by using a silica colloidal crystal as a template.The upper part of inverse opal structure and the luminescence characteristics of dicyanodistyrylbenzene-based moiety endowed the resulting bilayer photonic film with structural color arising from coherent Bragg reflection and fluorescence properties,respectively.A fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN.More importantly,the photo-induced irreversible Z/E photoisomerization of dicyanodistyrylbenzene-based moiety in the photonic film led to both a reflection spectral shift and an observable fluorescence variation.On the basis of this effective phototuning process,microscopic patterning ofphotonic film was developed under both fluorescence mode and reflection mode.The work demonstrated here provides a new route to construct photo-responsive photonic film.     

Light-induced anchoring transition in a 4,4'-disubstituted azobenzene nematic liquid crystal

The behaviour of a liquid crystalline azobenzene material possessing a nematic phase was studied under UV illumination. It was found that a uniformly aligned planar sample of the azobenzene undergoes a reversible orientation transition to homeotropic; this can be interpreted as an anchoring transition caused by the photo-isomerization of the azobenzene moiety in the molecular structure of the nematogen. A simple model taking into account the changes in the molecular shape, as well as the magnitude of the molecular net dipole moment, and the changes in the surface density of the cis-isomers with UV exposure time is proposed to explain the light-induced anchoring transition in the azobenzene nematic.     

Light-induced anchoring transition in a 4,4'-disubstituted azobenzene nematic liquid crystal

The behaviour of a liquid crystalline azobenzene material possessing a nematic phase was studied under UV illumination. It was found that a uniformly aligned planar sample of the azobenzene undergoes a reversible orientation transition to homeotropic; this can be interpreted as an anchoring transition caused by the photo-isomerization of the azobenzene moiety in the molecular structure of the nematogen. A simple model taking into account the changes in the molecular shape, as well as the magnitude of the molecular net dipole moment, and the changes in the surface density of the cis-isomers with UV exposure time is proposed to explain the light-induced anchoring transition in the azobenzene nematic.     

Photocontrolled extraction ability of azobenzene-bridged azacrown ether

The extraction equilibrium of alkali metal salts between water and benzene with an azobenzene-bridged azacrown ether(I) is affected by photo(uv)-irradiation. This indicates that the binding ability of (I) can be controlled by photo-induced cis-trans isomerism of the azobenzene moiety.     

偶氮苯聚合物的光控图案化

将自组装得到的聚苯乙烯胶体晶体,利用反应离子刻蚀和软刻蚀法复形到偶氮苯聚合物膜表面,获得六方非紧密排列的偶氮苯聚合物半球状阵列微图案膜。采用场发射扫描电子显微镜(FESEM)、原子力显微镜(AFM)和接触角测量仪等对膜的微阵列结构和表面润湿性能进行了表征。研究了光照对膜微图案结构和润湿性能的影响。结果表明:基于偶氮苯基团的光致取向特性,偶氮苯聚合物膜的微图案在偏振光照射下,可由初始的半球状阵列微结构形变成纺锤状和椭球状等结构,这种微结构的改变可以改变膜表面润湿性,实现偶氮苯聚合物膜表面不同微图案和润湿性能的光照调控。     

Exploration of Stable Sonoelectrocatalysis for the Electrochemical Reduction of Oxygen

A series of modified electrodes were prepared both via solvent evaporation and electrochemical cycling of azobenzene and derivatives and various quinones and assessed for their suitability as oxygen reduction electrocatalysts and sonoelectrocatalysts. Glassy carbon electrodes were modified via solvent evaporation with 1,2‐dihydroxyanthraquinone and 1,2‐diazonium‐9,10‐anthraquinone while edge plane and basal plane pyrolytic graphite electrodes were modified by the same procedure with 9,10‐phenanthraquinone. The stability of the attached moiety was accessed in each case under ultrasound. For comparison the same electrode substrates were modified with 9,10‐phenanthraquinone by electrochemical cycling and also exposed to ultrasound. The observed results suggest the use of the glassy carbon electrodes modified with azobenzene and derivatives via solvent evaporation as the optimal carbon based sonoelectrocatalysts for oxygen reduction in term of stability under insonation and high catalytic rate.     

Alignment control of liquid crystals on surface relief gratings

Liquid crystal alignment layers of a high T_g polymer containing an azobenzene moiety are prepared by photofabrication of a surface relief grating (SRG). The interference pattern of a circular and linearly polarized Ar⁺ laser beam generated the surface relief grating and the morphology was detected by atomic force microscope. The optical anisotropy of the films was investigated by polarizing optical microscopy. The orientation of the optical axis of the film mainly depends on the direction of the initial polarization plane. Nematic liquid crystals were aligned parallel to the direction of the grating, but the pretilt angles of the liquid crystals were nearly zero. Irradiation with homogeneous linearly polarized light could also align liquid crystals, but this alignment capability was weaker than that of the SRG film.     

氯霉素分子印迹复合膜的制备及电化学

采用电化学聚合法合成了对氯霉素（CAP）有快速响应和高灵敏度的聚苯胺/聚吡咯分子印迹复合膜修饰电极。 通过微分脉冲伏安法、扫描电子显微镜对制备的分子印迹复合膜的电化学性质及表面形貌进行了表征。 结果表明,以铁氰化钾为电化学探针,该膜对CAP的测定电化学信号响应快速、灵敏度高、选择性和膜再生性能良好。 对CAP检测的线性范围为5.00×10-8～1.05×10-6 mol/L,检测限为2.09×10-9 mol/L。