Control of Induced Chirality in Optically Active Poly(N‐propargylcarbamate) Films by Solvent Vapor

Chiral polyethyne derivatives with lyotropic liquid‐crystalline properties are found to be able to self‐assemble, forming two chiral organizations with opposite handedness in solid thin films by selection of the casting solvent and its concentration. After the film preparation, chiral organization could also be induced by simple exposure to an appropriate organic solvent's vapor for several minutes without thermal treatment. Furthermore, irreversible inversion of the handedness of the chiral organization in the film could be achieved by exposure to solvent vapor. Chiral polyethyne derivatives with lyotropic liquid crystalline properties exhibited characteristic induced chirality in their films, which was detected by circular‐dichroism spectroscopy. The induced chirality in the film was highly dependent on the casting solvent and concentration. As a versatile method, exposure to organic‐solvent vapor at room temperature induced and inversed the characteristic chirality in the film.