Single Particle Semi‐Reversible Solvatochromic Sensor

A semi-reversible solvatochromic sensor is presented using polydiacetylene@polydimethylsiloxane (PDA@PDMS) core-shell particles fabricated via a co-flow microfluidic method. Exposing these particles to specific volumes and types of solvents triggers the migration of unpolymerized 10,12-pentacosadiynoic acid (PCDA) monomers from the PDA core to the PDMS shell, enabling distinctive semi-reversible color-change patterns in both regions during repeated cycles of UV exposure and solvatochromism. The solvent-induced response of PDA@PDMS varies according to solvent permeability and solvent-mediated PCDA transport efficiency, which are influenced by PDMS swelling, solvent boiling point, and PCDA solubility. Compared to bare PDA particles and PDA/PDMS composite particles, PDA@PDMS exhibits superior solvent differentiation through distinct solvatochromic responses across a range of solvents. These PDA@PDMS core-shell particles offer a robust platform for real-time, precise multi-solvent detection, with significant potential for analytical and environmental monitoring applications.