Investigation on a novel photo-responsive system formed by N-methyl-N-cetylpyrrolidinium bromide and ortho-methoxycinnamic

In this work, we report a simple class of photo-responsive system that consists of cationic surfactant , N -methyl- N -cetylpyrrolidinium bromide (C 16 MPB), and the photoresponsive organic derivative, trans - ortho -methoxycinnamic acid ( trans -OMCA). The system is studied by UV spectra, cryo -transmission electron microscopy, and rheological measurements. C 16 MPB and trans -OMCA in basic aqueous solution can self-assemble to form viscoelastic wormlike micelles . Upon exposure to UV light , OMCA undergoes a photoisomerization from trans to cis , which results in a change of the geometry of the C 16 MPB–OMCA complexes. The wormlike micelles can transform into spherical or rodlike micelles. We hope this study may enrich the understanding of photo-responsive wormlike micelles composed by cationic surfactants and photo-sensitive additives in water.