A dual-functional polyaniline film-based flexible electrochemical sensor for the detection of pH and lactate in sweat of the human body

A flexible dual functional electrochemical sensor based on macroscopic polyaniline (PANI) film is reported. The PANI film is prepared by interfacial synthesis without any additional templates and surfactants, and is easily transferred from the water surface to any substrate. The surface of PANI film is flat and has a certain degree of crystallization. The PANI film exhibits good electrochemical properties, which is attributed to the order structure of PANI. The flexible sensor based on PANI film exhibits good electrochemical performances to pH and lactate. And the flexible PANI sensor has good reproducibility, selectivity and long-term stability. Meanwhile, the PANI sensor is also applied to detect the actual sample (such as food and human sweat), and the results are in accordance with the commercial pH meter, indicating the reliability of the PANI sensor. [Display omitted] •A large area, uniform, and crystalline PANI film by the interface synthesis method at the air-water interface.•The PANI film can float on the water and be directly transferred to substrates for direct testing without falling off.•The PANI film exhibits good electrochemical performances to pH value and lactate concentration of sweat.•The actual sample was tested, and the PANI film sensor still has good performance.