Polarized Fluorescence of N-Salicylideneaniline Derivatives by Direct Exchange from Photoaligned N-Benzylideneaniline Side Groups in Liquid Crystalline Polymeric Films

Photoalignment of liquid crystalline polymer with N-benzyl-ideneaniline (NBA) side groups and subsequent in situ exchange achieves polarized fluorescence of oriented N-salicylideneaniline (SA) derivatives. In situ hydrolysis of NBA and condensation with 2-hydroxybenzaldehyde derivatives form oriented SA side groups. SA exhibits excited state intramolecular proton transfer (ESIPT), inducing polarized fluorescence with a 2.3 polarization ratio. The emissive wavelength depends on the 2-hydroxybenz-aldehyde derivative. Stepwise formation of different oriented SA side groups allows for color tuning of the oriented film.