Formation and Sensing of Polyethyleneimine-Assisted Lyotropic Chromonic Liquid Crystal Droplets

Lyotropic chromonic liquid crystal (LCLC) droplets hold significant potential in both scientific research and practical applications. The incorporation of polyethyleneimine (PEI) and its impact on LCLC droplet formation present a compelling puzzle. This study reports the fabrication of micrometer-sized LCLC droplets through the self-assembly functionalization process by integrating cationic polymer PEI into a disodium cromoglycate (DSCG) solution. Notably, the droplet morphology can be reversibly altered between bipolar and radial configurations by modulating the pH of the surrounding aqueous solution, an effect attributable to the contraction of PEI chains. The findings indicate that the PEI-DSCG system can serve as a pH indicator in purified water and detect glucose concentrations as low as 0.1 mM by observing the ratio of bipolar to radial droplets under crossed polarizers. This investigation enhances the understanding of polymer-LCLC interactions and advances new avenues for developing pH-responsive systems and glucose-sensing technologies.