Studying the chirality of polymerized 10,12-tricosadynoic acid LB films using SHG polarized angle dependence and SHG-CD method

Using optical second harmonic generation (SHG) measurements, polymerized 10,12-tricosadynoic acid (PTDA) monolayer on quartz substrate were investigated. SHG polarized angle dependence measurements and optical second harmonic generation circular dichroism (SHG-CD) measurements were carried out to reveal the chirality of PTDA monolayer. It was revealed that the chiral PTDA films were formed when subphase solution contains Cu(II) ions, while the chirality for PTDA LB films were not formed when subphase solution is pure water or contains Cd(II) ions. The conformational change of the polydiacetylene chain due to metal ions was found the most probable origin.