Langmuir films of dichroic dyes with fluorescent properties

Langmuir films of various dyes, namely derivatives of 3,4,9,10-perylenetetracarboxylic acid and 3,4,9-perylenetricarboxylic acid, derivatives of naphthalenebicarboxylic acid and derivatives of naphthoylenebenzimidazole were investigated. Surface pressure-mean molecular area isotherms were recorded from which the alignment of the molecules in a monomolecular layer at the air-water interface was determined. It was found that both the stability and the rigidity of the monolayer are strongly a.ected by the molecular structure of the side groups substituted on the skeleton of the molecule.