Macrocyclic amphiphiles. Part 2. Multi-point adsorptivity of the crown conformer of calix[4]resorcinarenes and their derivatives on surfaces of amorphous polar substrates

The adsorption behavior of the crown conformer of calix[4]resorcinarenes (CRAs), cyclic tetramers of resorcinol and aliphatic aldehydes, and their O-carboxymethoxylated and O-hydroxyethyloxylated derivatives on a quartz surface was investigated. The adsorption of the macrocyclic amphiphiles from solutions of less polar solvents such as toluene at concentrations of >10(-3) mol dm(-3) obeyed the Langmuir equation to give monomolecular layers. The absorption equilibrium constant for CRA was two orders of magnitude greater than that of the corresponding resorcinol. Such efficient adsorptivity of the macrocyclic compounds arises from their characteristic structures which possess eight hydrogen-donating polar residues on the same rim of the cylindrical molecular skeleton. CRA molecules are also adsorbed on the surface of a poly(vinyl alcohol) thin film, suggesting that these cyclic tetramers provide a general procedure to give monomolecular layers deposited on polar surfaces of amorphous solids.