Studies on the aggregation behaviour of a side-chain liquid crystalline polymer in Langmuir-Blodgett films

The aggregation behaviour of a newly synthesized ferroelectric side-chain liquid-crystalline polysiloxane (denoted as PSLC) in Langmuir-Blodgett (LB) films has been investigated. The surface pressure(pi)-area (A) isotherm and hysteresis experiments fur arachidic acid (AA)/PSLC mixed monolayer confirm existence of aggregation or phase-separation during compression. From the UV-Vis spectra, we can clearly see H-aggregate formation. To study the aggregate structure and molecular parking of PSLC, cyclic voltammetry combined with transmission electron microscopy and scanning electron microscopy morphology observations was used. The exciton model previously advanced by Kasha and coworkers is successfully introduced for a qualitative explanation of the spectra observed in the LB films.