An Inquiry-Based General Chemistry Laboratory: Preparing a Moisture Responsive Flexible Sensor

Flexible sensors have gained increasing interest in diversified fields in modern society. The selection of suitable active materials plays an important role in dominating the performance of sensors. Recently, the strategy of solid-phase molecular self-assembly (SPMSA) has been used to make functional materials by a simple and reproducible method. Herein, we introduce the latest research results in a supramolecular film sensor with humidity responsiveness into the general chemistry laboratory for the first-year undergraduate. In this experiment, the commercially available reagents N,N,N-Trimethyl-1-dodecanaminium bromide (DTAB) and sodium polystyrenesulfonate (PSS) have been used to make a moisture responsive flexible sensor by doping with carbon nanotubes (CNTs) by a simple procedure at room temperature. Students employ several key characterization techniques to evaluate the sensor’s properties, including Raman spectroscopy, X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM) for structural analysis, a tension machine for mechanical flexibility testing, and an electrochemical workstation for evaluating humidity-responsive performance. In the 5-week laboratory experience, students worked in teams to carry out tasks including experimental synthesis, structural and performance characterization of the film sensor, data analysis, and presenting the results. This inquiry-based project provides students with experience similar to those in real research for first-year undergraduate students, which effectively stimulates their interest and enhances their competencies in scientific research. Additionally, the techniques and concepts involved in this experiment are highly relevant to materials science, polymer chemistry, and engineering courses. Thus, this experiment is also well-suited for students in these advanced fields, where a deeper understanding of intermolecular interactions and material properties is essential.