Integrating Biobased Shape Memory Polymers into Undergraduate Materials Science Laboratories

Intelligent polymeric materials have aroused increasing research interest recently; in this article, we present a laboratory experiment that involves the fabrication and characterization of shape memory hydrogels, an important kind of intelligent polymeric material, to undergraduate students. Shape memory hydrogels could store temporary shapes under certain circumstances and generate shape transformation and recovery to the original shapes upon external stimuli. Therefore, they have shown great application potential in various emerging fields including artificial muscles, soft robots, and flexible electronics. In this experiment, tannic acid–gelatin hydrogel has been fabricated via simple mixing via the formation of hydrogen bonds; students could compare the mechanical properties of the hydrogel at different temperatures by stretching, twisting, and load-bearing tests. Moreover, the shape memory performance and working capacity of the hydrogel were investigated using simple laboratory setups. The experiment is safe, convenient, and adoptable to most undergraduate laboratory courses. Through this practical class, undergraduate students could get a better understanding of smart polymers and learn how to prepare and investigate the properties of materials, which can further stimulate their interest in smart materials and devotion to scientific research in the future.