Upcycling of the Used-Factory Film Sheets to Electrochemical Humidity Sensor

Abstract

The primary objective of this study was to upcycle used factory film sheets, thereby adding value to these materials and mitigating the accumulation of industrial waste. Specifically, our research focused on developing an electrochemical sensor for humidity measurement. Initially, the plastic sheets underwent a comprehensive analysis of their physical and chemical properties. Subsequently, they were coated with graphene oxide at varying concentrations (0.5%, 1.0%, 1.5%, and 2.0% w/v) to investigate the electrical response of the electrochemical sensor using cyclic voltammetry. Humidity measurements were conducted using the LCR meter based on the electric method. The study revealed that the waste film sheets were of Polydimethylsiloxane type, with a thickness of 0.105 mm, showcasing flexibility and suitability for surface modification through laser screening. To enhance the conductivity properties, the electrochemical sensor was coated with 1.0% w/v graphene oxide. This modification enabled accurate humidity measurements, establishing a relationship between humidity (x) and electric capacity (y) through a second-degree polynomial equation: y = 0.0013x^2 + 2.7902x – 51.17, with an R^2 value of 0.971. Furthermore, the morphology analysis of the graphene oxide on the modified sensor surface revealed a stacked configuration with a hexagonal shape. The specific surface area of graphene oxide was calculated to be 74.6269 square millimeters per gram. This innovative approach not only showcases the flexibility and adaptability of Polydimethylsiloxane-based film sheets but also demonstrates the potential of graphene oxide coatings in developing efficient and reliable humidity sensors, contributing significantly to the field of environmental sustainability and sensor technology.