Detection of the reversible flow behavior of 4-heptyloxy-4′-cyanobiphenyl monolayer at air–water interface by compression and expansion with Maxwell displacement current and optical second harmonic generation

The flow behavior of 4-heptyloxy-4′-cyanobiphenyl (7OCB) monolayer is studied during compression and expansion by Maxwell displacement current (MDC) and second harmonic generation (SHG) measurement. It is found that in-plane molecular flow induced reorientation of 7OCB monolayer in L2 and L2′ phases of the monolayer is reversible. It is concluded that the MDC-SHG method is available for exploring the flow behavior of monolayers.