Monolayer flow and in-plane orientation induced by a rotating disk in Langmuir and Langmuir-Blodgett films of a merocyanine dye

We have demonstrated that the rotating-disk method, which was proposed by Mingotaud et al. [J. Phys. Chem. 99, 17 068 (1995)] recently, is effective to induce in-plane orientation in the Langmuir-Blodgett films of merocyanine dye-behenic acid mixtures. To clarify the orientation mechanism, the monolayer flow due to the disk has been observed directly and interpreted by an analytical model incorporating a non-Newtonian behavior of the films. Based on this observation, a steady-state orientation-distribution function has been calculated. The comparison of the calculated orientation-distribution function and the experimental data shows that our model gives a guideline of the rotating-disk method.