FABRICATION OF FLEXIBLE ELECTROCHEMICAL DEVICES BASED ON PYROLYZED PAPER MODIFIED WITH POLYDOPAMINE
Paper analytical devices are a good alternative among the sensors used in the pharmaceutical, food and agro industries, as they are based on a simple, low cost and biodegradable material. Among the production techniques for these devices, paper pyrolysis is the one that has been gaining prominence for making the material itself conductive. Therefore, this work will explore paper pyrolysis for the development of electrochemical sensors. After pyrolysis, it is interesting that it is functionalized, so in this sense here the substrate will be modified with polydopamine. After the functionalization process, it was observed that the presence of polydopamine film introduces chemical functionalities rich in oxygen (O-C=O) and nitrogen (R-NH2, R2-NH, =N-R) which decreases the contact angle from 114° to 0°. When performing annealing at different temperatures on polydopamine, changes in the chemical composition of the surface occur, but the reasons are possible to be controlled by temperatures. These chemical modifications were monitored using SEM, XPS, confocal microscopy, Raman, contact angle and cyclic voltammetry measurements. Functionalization brings superhydrophilicity to the paper, the annealing of polydopamine varies the chemical composition of the coating, thus alters the wettability (0 to 89°), improves the resistivity (75 to 62 mΩ cm-1) and collaborates in the reduction of ∆ Ep (240 mV to 68 mV) when the temperature reaches 1000°C. Therefore, using the control of these parameters will be very useful for the development of sensors and biosensors aimed at gaining sensitivity and future functionalization processes to immobilize biological recognition agents.