Design and synthesis of polymers for chiral photonics

Chiral photonics deals with enantioselective polarization control of linear and nonlinear optical functions and holds a great promise for a wide range of applications including optical signal processing, biosensing, and chiral bioimaging. Development of chiral materials with optical activity exceeding that of natural materials therefore becomes a prerequisite to realizing the full potential of this field. Herein, we report on a study of structure-property relations of two chiral polymers with ester functional groups in lateral branch. To enhance rotational strength, the macroscopic measure of chirality, we employ a fluorene-quinoxaline motif in the monomer unit. To the best of our knowledge, we find the optical activity of one of the studied polymers to be the highest reported so far. Theoretical calculations reveal a correlation between the topological conformations and the simulated CD spectra in agreement with the experimental measurements and help clarify the mechanism of optical activity enhancement that could create insight for further enhancement of chirality.