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1.
水介质中吡咯的电化学聚合反应 总被引:8,自引:0,他引:8
研究了扫描电位上限对循环伏安法制备聚吡咯膜性能的影响,吡咯在水溶液中于玻碳电极表面化学聚合的起始电位为0.58V,在聚吡咯(Ppy)修饰电极表面聚合的起始电位为0.55V,当聚合电位上限在0.80V以上时,Ppy的氧化还原反应可逆性变差,同时,氧化电位过高将导致Ppy膜导电性能下降;研究了聚合介质对循环伏安法制备导电聚吡咯膜的影响,实时观察了吡咯(Py)聚合过程溶液中质子含量的动态变化,发现Py聚合伴随有质掺杂←→释放过程;结合Ppy膜的元素分析、ESR分析和IR光谱分析,总结出了水介质中电化学聚合高导电性聚吡咯膜的条件。 相似文献
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制备了钨钴酸根与钨铜酸根阴离子掺杂的聚吡咯膜电极,并对其电化学行为进行了初步研究。结果表明,在微酸性或近中性的溶液中,该电极有良好的电化学稳定性及循环伏安行为。聚吡咯膜对钨铜酸根阴离子的第2个氧化还原过程有明显的催化作用。电子自旋共振显示杂聚阴离子与聚吡咯分子链形成了某种复合物,此复合物对聚吡咯电结构的影响随阴离子的不同而异。 相似文献
3.
利用电化学固定化方法制备了聚吡咯/辣根过氧化物酶(PP/HRP)膜电极,并研究了其电化学行为,在除氧的磷酸盐缓冲液介质中,PP/HRP电极加速H2O2的还原,归因子酶加成物的直接电子传递,探索HRP与电子传递体K4Fe(CN)6在聚吡咯(PP)膜中的同时固定化条件及其膜电极的电化学行为,实验证实,K4Fe(CN)6在酶膜中的存在使得H2O2的还原电位强烈正移,在-0.05V的工作电位下能对H2O2 相似文献
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用恒电流法分别聚合了掺杂对甲苯磺酸根(pTS-)和十二烷基磺酸根(DS-)的聚吡咯膜(PPy/pTS和PPy/DS),通过循环伏安法(CV)和电化学阻抗法(EIS)测试了聚吡咯膜在NaCl溶液中‘过电位’电化学过程前后及不同电位下聚吡咯膜的电化学性能.同时,通过嵌入和脱出Na+和Cl-离子的聚吡咯膜在特定溶液中电化学阻抗图谱,研究了离子的嵌入对聚吡咯膜电化学性能的影响.结果表明‘过电位’现象可以提高聚吡咯膜的离子电导率和膜电容,Cl-离子的嵌入能提高PPy/pTS的电导率,而Na+离子的嵌入对聚吡咯膜的电导率影响不大.另外,嵌入离子对聚吡咯膜形貌的改变会对聚吡咯膜的离子传导率有一定影响,从而导致膜的电化学阻抗的变化. 相似文献
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功能聚吡咯膜修饰电极的制备及其应用 总被引:2,自引:0,他引:2
本文对功能聚吡咯膜修饰电极的制备及其在电化学催化、电化学释放、分子器件、电变色效应、生物传感器以及电化学分析等方面的应用进行了综述,引参考文献五十篇。 相似文献
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磷钼杂多酸—聚吡咯膜修饰碳纤维微电极的制备及其电化学性能研究 总被引:2,自引:2,他引:2
用电化学方法将磷钼杂多酸催化剂固定在导电聚吡咯膜电极上,从而制得具有表面功能的磷钼杂多酸掺杂的聚吡咯膜修饰碳纤维微电极。该电极既保持了磷钼杂多酸的电化学活性和电催化性能,又具有良好的稳定性,在酸性水溶液中不仅能催化还原ClO3而且对NO6-2离子有有更显著的电催化还原作用。 相似文献
9.
聚吡咯薄膜中茜素红S的电化学特性 总被引:4,自引:0,他引:4
利用循环伏安法研究了聚合电位和聚合电量对茜素红S掺杂聚吡咯薄膜修饰玻碳电极性质的影响,考察了不同电位范围内修饰电极的电化学特性.发现在茜素红S的氧化还原过程中存在着茜素红S分子与聚吡咯链的相互作用,且这一相互作用敏感于扫描正电位限.基于实验结果,提出了可能的茜素红S在电极表面聚吡咯膜内的氧化还原机理. 相似文献
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Génesis Adilene Grijalva Bustamante Brianda María Salazar Salas María Mónica Castillo Ortega José Carmelo Encinas Dora Evelia Rodríguez Félix Lerma Hanaiy Chan-Chan Rosa Elena Navarro Gautrín Jorge Romero García Teresa del Castillo Castro 《先进技术聚合物》2023,34(2):621-633
The development of electro-stimulated drug release devices is an innovative approach to attain the drug delivery in accurate doses at target sites in a programmed manner. In this work, novel electroactive nanocomposite hydrogels were prepared by encapsulating green-synthesized polypyrrole (PPy) colloids within chondroitin sulfate (CS) networks during the self-crosslinking of CS via N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide chemistry. The structural and morphological properties of CS/PPy hydrogels were studied by Fourier-transformed infrared spectroscopy, scanning electron microscopy, and swelling kinetic measurements. The chemotherapeutic agent 5-fluorouracil (5-FU) was loaded into CS/PPy samples by hydrogel swelling method, or alternatively, by pre-incubating the drug in polymer mixture before crosslinking. Different electrical stimulations can be used to switch ON and accurately tune the 5-FU delivery from GG/PPy hydrogels. A single pulse potential of 5 V switched on the drug delivery up to 90% from nanocomposite hydrogel, in contrast to the low 5-FU amount released in a passive form (< 20%). PPy electroactive behavior played a determining role as the main driving force in 5-FU release activation. Cytotoxicity of hydrogels with and without 5-FU was examined in normal and cancer cells. Considering the high cytotoxicity of 5-FU, the ON/OFF 5-FU release patterns evidenced the potential of CS/PPy hydrogels for electrically controlled drug delivery in implantable or transdermal drug release devices. 相似文献
12.
Coating metals on cellulose–polypyrrole composites: A new route to self-powered drug delivery system
Dongtao Ge Xiaoning Ru Shimin Hong Shuhui Jiang Jing Tu Jun Wang Aifeng Zhang Shan Ji Vladimir Linkov Bin Ren Wei Shi 《Electrochemistry communications》2010,12(10):1367-1370
A self-powered drug delivery system based on cellulose–polypyrrole (PPy) composite film was developed. The cellulose–PPy composite film was prepared by deposition of drug-contained PPy film on the inner and outer surfaces of a porous cellulose film. After coating a thin layer of active metal such as magnesium on the one side of the composite film, the drug stored in the PPy film can be released autonomously upon exposure to the electrolyte solution. It was confirmed that the drug release from the system followed the galvanic cell mechanism. The amount of the drug released and the release rate of drug can be controlled by adjusting the thicknesses and types of the active metals, respectively. Since the cellulose film is biodegradable and the system obtained is flexible and lightweight, it is therefore expected that this drug delivery system can find in vivo applications. 相似文献
13.
电化学控制释放三磷酸腺苷 总被引:3,自引:0,他引:3
在含有甲苯磺酸钠和吡咯的水溶液中电化学合成聚吡咯膜.当膜在三磷酸腺苷(ATP)的溶液中氧化时,ATP掺入膜内;当膜还原时ATP从膜中释放出来, 释放出的ATP的量可由紫外可见光谱法测定. 相似文献
14.
A new method for the extraction of both anions and cations is proposed using electro-synthesized polypyrrole (PPy) and overoxidized sulfonated polypyrrole film (OSPPy). In situ anion (chloride, nitrate, sulfate) and cation (calcium, magnesium) uptake and release were examined under controlled potential conditions for prospective applications in electrochemically controlled solid-phase extraction (EC-SPE). The PPy film was used as an anode (anion-exchanger) and OSPPy film was used as a cathode (cation-exchanger) material and reverse order of the electrodes were investigated in EC-SPE. This new cell arrangement containing two ion exchanger polymer electrodes was developed to provide in situ removal of both anions and cations from aqueous solution. Simple preparation of the film coatings on a platinum plate was possible using a constant potential method. Applied positive and negative potentials facilitated the in situ extraction and desorption of ions, respectively. Both anions and cations were desorbed into sample aliquot and were determined by ion chromatography (IC). The method was validated using a standard reference material and tested for the determination of the ions in real water samples. 相似文献
15.
An electrically controlled drug release (ECDR) system based on sponge-like nanostructured conducting polymer (CP) polypyrrole (PPy) film was developed. The nanostructured PPy film was composed of template-synthesized nanoporous PPy covered with a thin protective PPy layer. The proposed controlled release system can load drug molecules in the polymer backbones and inside the nanoholes respectively. Electrical stimulation can release drugs from both the polymer backbones and the nanoholes, which significantly improves the drug load and release efficiency. Furthermore, with one drug incorporated in the polymer backbone during electrochemical polymerization, the nanoholes inside the polymer can act as containers to store a different drug, and simultaneous electrically triggered release of different drugs can be realized with this system. 相似文献
16.
Electrochemically aided solid phase microextraction: conducting polymer film material applicable for cationic analytes 总被引:1,自引:0,他引:1
Khalid R. Temsamani Özcan Ceylan Brian J. Yates Serhan Öztemiz Thompson P. Gbatu Apryll M. Stalcup Harry B. Mark Wlodzimierz Kutner 《Journal of Solid State Electrochemistry》2002,6(7):494-497
The cation uptake and release properties of a poly(pyrrole-sulfated β-cyclodextrin) (PPy-SβCD) film electrode have been investigated
under both open circuit and controlled potential conditions for prospective applications in electrochemically aided solid-phase
microextraction (EA SPME). The EDAX and ion chromatography results show that the K+ and Na+ cation uptake is enhanced if a small negative potential is applied to the electrode in the range where PPy is in its neutral
form. These cations are released rapidly from the film if the applied potential is switched to the value at which PPy is converted
to its positively charged form, i.e., oxidized state. The cation ingress and egress mechanism is affected both by the cation
exchange at the negative sulfate moiety on the cyclodextrin sites and electrostatic interactions generated by the applied
potential. The electrochemical "switching" capability increases the speed of the cation uptake and release, presumably due
to electro migration, as compared to the open circuit ion exchange which is controlled solely by diffusion. Our preliminary
fundamental results show that the PPy-SβCD film is suitable for the future design of EA SPME devices.
Electronic Publication 相似文献
17.
A pharmaceutically active compound, 5-fluorouracil (5-FU) has been firstly intercalated into layered double hydroxide with the restructure method. Powder X-ray diffraction and spectroscopic analysis indicate that 5-FU molecule is stabilized in the host interlayer by electrostatic interaction and intermolecular interaction, and that the orientation of 5-FU is different when changing the pattern of aging treatment or the swelling agent. The release studies show that a rapid release of the drug during the first 40 min is followed by a more sustained one, and that the total amount of drug released from hybrid material into the aqueous solution is almost 87% and 74% at pH 4 and 7, respectively. The studies mentioned above suggest that layered double hydroxide might be used as the basis of a tunable drug delivery carrier. 相似文献
18.
A polymeric system capable of delivering 5-fluorouracil (5-FU) at increased rates on demand by external microwave irradiation was developed. Sustained-release systems were made by incorporating 5-FU into an ethylene-vinyl alcohol copolymer. When exposed to release medium, the delivery systems released the drug slowly and continuously. Upon exposure to microwave irradiation, the drug was released at a much higher rate. Release rates returned to base line levels when the microwave irradiation was discontinued. This study demonstrated that release rates of 5-FU from a polymer matrix can be increased at desired times by external microwave irradiation. 相似文献
19.
M. Cristina De Jesus R. A. Weiss Yuping Chen 《Journal of Polymer Science.Polymer Physics》1997,35(2):347-357
Electrically conductive composite surfaces were prepared by a diffusion-controlled in situ polymerization of pyrrole in the surface layer of sulfonated polystyrene ionomer films. Premolded films of the ionomer sulfonic acid derivatives were sequentially immersed in aqueous solutions of pyrrole and FeCl3, and polymerization occurred only where both the monomer and the oxidant were present. The penetration of the polypyrrole (PPy) into the film was controlled by varying the immersion time in the monomer solution. The amount of PPy produced depended on the immersion time of the film in the monomer and the degree of sulfonation of the ionomer. Surface conductivities of 10−4-10−1 S/cm were achieved with PPy concentrations from 2 to 22 wt % and composite layers as thin as 15 μm. Intermolecular interactions occurred between PPy and the ionomer by proton transfer. Incorporation of PPy also increased the tensile strength of the ionomer film, significantly increased its modulus above Tg, and inhibited melt flow. © 1997 John Wiley & Sons, Inc. 相似文献
20.
Direct Visualization and Semi‐Quantitative Analysis of Payload Loading in the Case of Gold Nanocages
Miaoxin Yang Wenxia Wang Jichuan Qiu Meng‐Yi Bai Younan Xia 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(49):17835-17838
Upon incubation with Au nanocages, pyrrole (Py) molecules can enter the cavities by diffusing through the porous walls and then be polymerized to generate a polypyrrole (PPy) coating on the inner surface. The thicknesses of the PPy coating can serve as a direct indicator for the amount of Py molecules that diffuse into the cavity. Py molecules are able to diffuse into the cavities throughout the polymerization process, while a prolonged incubation time increases the amount of Py accumulated on both inner and outer surfaces of the nanocages. Furthermore, it is demonstrated that the dimensions of the cavity and the size of the pores in the wall are not critical parameters in determining the loading efficiency, as they do not affect the thickness of the PPy coating on the inner surface. These findings offer direct evidence to support the applications of Au nanocages as carriers for drug delivery and controlled release. 相似文献