Electrochemical Sensors Based on Electropolymerized Films

Chemical sensors are the devices that provide a certain type of responses related to the quantity of a specific species. All chemical sensors consist of a transducer and a chemically selective layer. The transducers transform the response into a detectable signal on modern instrumentation, and the chemically selective layer isolates the response of the analyte from its immediate environment. According to the properties to be determined, chemical sensors can be classified as electrical, optical, mass or thermal sensors. Among all of them electrochemical sensors obtained more attention because they are sensitive and selective, fast and accurate, portable and in expensive. The modification of electrodes surfaces by some special layers has been the major growth area in electrochemical sensors in recent years. Compared to conventional electrodes, greater control of electrode characteristics and reactivity is achieved by surface modification, since the immobilization transfers the physicochemical properties of the modifier to the electrode surface. This process could impart a high degree of selectivity or sensitivity to the electrochemical transducers. Different procedures such as chemical reaction, chemisorption, composite formation or polymer coating have been used to modify electrodes. Several papers have reviewed the application of the modified electrodes in electrochemical sensors areas [1] Electrochemical polymerization (ECP) refers to the application of electrochemical methods in the cathode or anode during the polymerization reaction process. The polymerization method provides a new current or potential control factor, so some important advantages were recognized at the beginning of its development such as: short process and low cost. The film thickness and composition can be achieved easily by controlling the electrochemical parameters during the electrochemical process. In addition, electrochemical polymerization can make raw monomer aggregate directly on the substrate film to avoid the use of a large number of volatile organic solvents to achieve the aim of clean production. Because of these excellent features, electropolymerization method holds a promising future for construct simple design, high stable, rapid response and enhanced selectivity sensors. This review will briefly present the development and application of the sensors prepared by electropolymerization method in the recent ten years. The main goal of this contribution is not to collect all papers published recently, but to discuss the development and advantages of the electropolymerized films for analytical purpose. For application, we specifically focused on the most recent and promising applications of those sensors in environmental and clinical monitoring.