Visualization of pH Oscillating Reactions with Aggregation-Induced Emission: A Comprehensive Chemistry Experiment for Undergraduates

Visualizing nonequilibrium systems remains a major pedagogical challenge for undergraduate chemistry students. To address this gap, this paper presents a comprehensive, vertically integrated laboratory module that bridges organic synthesis, polymer chemistry, instrumental analysis, and physical chemistry. In this module, students synthesize and characterize a novel pH-responsive polymer probe, PEG-TPE-3N, with aggregation-induced emission behavior. This probe is further coupled with a pH-oscillating reaction within a continuous stirred tank reactor. Driven by the protonation-controlled aggregation of the probe, the resulting system transforms abstract nonequilibrium cycles into an intuitive, rhythmic fluorescence oscillation. By making concepts like feedback loops, autocatalysis, and nonequilibrium steady states macroscopically observable, this experiment enhances students’ comprehension of complex chemical dynamics and cultivates essential practical skills in interdisciplinary research.