Electrochemical Synthesis And Properties Of Thiophene-based Conjugated Microporous Polymers

Materials are the basis in the fields of science and technology,electronics,etc.Porous organic polymers?POPs?have attracted many researchers'attention due to their unique properties,especially the conjugated microporous polymers?CMPs?with high specific surface area and adjustable pore size.Thus CMPs have exhibited wide applications in the fields of separation,adsorption,energy storage,gas storageand catalysis,etc.However,there is few report about the CMPs as an electrochemical sensor modified materials.Electrochemical sensors possess various excellent advantages,such as quick response,low cost,conveinent operation and so on.Therefore,it's significant to serve the CMPs as the electrochemical sensing materials for its potential applications as well as the improvement of electrochemical sensors performance.At present,most of CMPs are obtained by chemical synthesis,which require expensive catalysts and harsh experimental conditions.In this dissertation,the different surface morphologies and properties of thiophene-based CMPs films were generated by one-step electrochemical polymerization.This facile and simple strategy didn't require any templates,surfactants and catalysts during the synthesis.The thin CMPs films modified electrode showed remarkable electrochemical response in the sensing of nitro compounds.The main points of this dissertation are summarized as follows:1.Three kinds of multifunctional thiophene derivatives were used as monomers,and the corresponding CMPs are obtained by electropolymerization.The experimental results showed that the formation processes of polymer film and the changes of surface morphology were due to the combined effect of generated bubble and polymerization rate.The bubble generated during the polymerization process acted as a soft template.The more the bubble generated,the more porous morphology were formed on the surface of the polymer film.If the polymerization speed was relatively high,the surface of the polymer film appeared non-porous or less porous morphology.The polymer films with different surface morphology could be obtained by controlling experimental conditions such as the potential of polymerization,electropolymerization method,electrolyte,and“trace water”.The different surface morphology will affect the wettability of the polymer film surface,resulting in different hydrophilic/hydrophobic polymer film surfaces.2.We synthetized different CMPs by electropolymerization of three thiophene-based monomers in two type of supporting electrolyte solutions,and each CMPs were used as electrode modifier for the detection of metronidazole.The experimental results showed that the-NO₂ of metronidazole could be directly reduced to–NHOH using the optimized CMPs modified glassy carbon electrode?GCE?,and increased reduction response were obtained when compared to the bare GCE.We chose poly?1,3,5-tris?2-thienyl??benzene?PTTB?obtained by electropolymerization for 5s using chronoamperometry?CA?method as the electrode modification material to study the electrochemical reduction process of metronidazole.The influence of scan rate,accumulation time,accumulation potential,and pH values were respectively investigated.The results indicated that the metronidazole molecules were passively formed the adsorption layer on the polymer films surface and then quickly reduced.The accumulation of metronidazole on the electrode surface didn't require the application of potential.The PTTB-GCE were immersed in the sample solution for 250 s,and the adsorption saturation state would be reached.The optimized pH value is 10.The linear ranges were 2-50?mol dm^-3 and 50-200?mol dm^-3,and the limit of detection was 16 nmol dm^-3.