Studies On Temperature-responsive Electrochemical Sensor Based On Poly(N-isopropylacrylamide) Copolymer

In order to develop an efficient and highly sensitive electrochemical sensor,a single material-modified electrode cannot meet the requirements of scientists.Scientists have attempted to combine different types of materials to form composites,thereby giving the electrode a unique combination of new materials that are not available in a single component.At present,the composite material combined polymer and nanomaterials is the most widely studied field.Thermoresponsive polymers are polymers whose molecular conformation is affected by temperature.Nanomaterials have excellent conductivity,and they are combined to obtain electrode-modified materials with temperature-sensitive properties.By regulating the ambient temperature to achieve the regulation of electrochemical performance,a new direction has been opened up for intelligent electrochemical sensors.The main aspect of this paper is as follows:(1)Synthesis of a temperature-responsive copolymer of poly(N-isopropylacry-lamide-co-butylmethacrylate)P(NIPAM-co-MBA)and nano-composite RG-MW-NTs.Based on these two materials,the PGM modified electrode was prepared.The modified electrode showed obvious reversibly temperature-controlled "on-off "detection effect with the LCST temperature(30℃)of P(NIPAM-co-MBA)as the boundary.Moreover the solution was repeatedly changed between 20℃ and 38 ℃.The peak current of ACOP at 38°C is basically not attenuated,indicating good reversibility.In the "on" state,the ACOP in the detection solution has a wide linear range.(2)The temperature-sensitive copolymer poly(N-isopropylacrylamide-co-met-hylmethacrylate)P(NIPAM-co-MMA)was synthesized by free radical polymeri-zation and the phase change occurred at 30°C.The PMN modified electrode was prepared by mixing P(NIPAM-co-MMA)with carboxylated carbon nanotubes(MWCNTs(COOH))and Nafion.With P(NIPAM-co-MMA)LCST(30°C)as the boundary,the PMN electrode has a clear temperature response "on-off" effect when detecting the hydroquinone(HQ)in the solution.When the solution temperature was changed several times between 22°C and 40℃,the response current of HQ at 40°C was basically no attenuation,signifying that the temperature switch is reversible.And in the "on" state the ACOP in the detection solution has a wide linear range and a lower detection limit.(3)The temperature-sensitive copolymer poly(N-isopropylacrylamide-co-nitro-xymethylacrylamide)P(NIPAM-co-NHMPA)and nanogold were synthesized.Both of them were mixed together and dropped on the surface of the glassy carbon electrode.Epinephrine in the test solution has a significant temperature "on-off"characteristic.The peak current value at 50°C is much greater than the peak current value at 150C,and the solution temperature is repeatedly changed between 15°C and 50℃.The peak current value at 50°C is not substantially attenuated.