Effect of nano clay platelets on the hybrid monolayer of a cationic oxazine dye: In-situ Brewster Angle Microscopic (BAM) study

Abstract

The present work investigates the adsorption of a cationic oxazine dye, cresyl violate acetate (CVA), into the anionic Laponite nano clay platelets through electrostatic interaction. The adsorption resulted in the formation of Clay-CVA hybrid molecules at the air water interface. CVA tagged nano clay platelets were further adsorbed onto a cationic surfactant, Octadecylamine (ODA), matrix at the air water interface and as a consequence a stable and almost uniform ODA-Clay-CVA hybrid monolayer was formed. The organization of hybrid molecules in Langmuir trough was changed under monolayer compression resulting in the formation of different sized and shaped domain structures. Surface pressure – area per molecule (π-A) isotherm studies and in-situ Brewster angle microscopic (BAM) studies were employed in this investigation to explore the monolayer chracteristics.