The solvatochromism and selective discrimination of dopamine substituted polydiacetylene vesicle towards typical water-miscible organic solvents

Abstract

Conjugated polydiacetylene (PDA) based functional materials are well known for the naked-eyes detectable colorimetric changes upon various environmental stimuli. And the solvatochromic property of PDA in response to organic solvents is appealing extensive research interests. In this work, at first dopamine substituted polydiacetylene was polymerized under UV irradiation in the form of vesicle in aqueous solution. Then some typical water-miscible organic solvents, including methyl alcohol, ethyl alcohol, acetone, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide and tetrahydrofuran, were added into the vesicle contained aqueous solution, among which tetrahydrofuran could induce the obvious blue-to-red color change of PDA immediately, while the other solvents could only induce partial blue-to-purple color change of PDA after a long time. The differentiated chromatic transition behavior of PDA vesicle to these seven organic solvents was studied thoroughly in both qualitative and quantitative characterization methods depending on UV–visible absorption spectroscopy, fluorescence, Raman, theoretical calculation and so on. To the best of our knowledge, this is the first report focusing on the selective solvatochromism of PDA upon exposure to different organic solvents in water, which will contribute to a deeper investigation and application extension of functional PDA materials in the future.