Introduction and Characterization of Simple Moisture-Driven Smart Paper for Chemistry Experiment in the Classroom: A Brief Guideline

Recently, smart sensing/actuation paper has attracted significant interest due to its potential usage as a sustainable component in future electronics, robotics, and intelligent sensing devices. In acknowledging the importance of this topic for the engagement of students at the university level in conjunction with Industrial Revolution 4.0, it is thus quite relevant to establish an approach that can be used to educate the students about the concept of smart paper and its characteristics. To achieve this objective, we have developed a smart paper that is electrically conductive and able to act as a humidity sensor or chemical-driven actuator that can be synthesized in a facile manner through the application of candle soot and commercial crayon on each side of A4 cellulose paper (100 gsm). The sensitivity of the fabricated paper-based sensor toward room humidity is reflected in the changing rate of electrical resistance, which is visually demonstrable by the blooming of an artificial flower made from the paper after exposure to moisture vapor. In conclusion, the activities performed during the reported guidelines may assist in cultivating practical knowledge for colloidal dispersion of carbon-based nanomaterials and chemical-driven actuators among students.