Formation of hybrid floating films composed of hydrophobic guests and amphiphilic calix[4]resorcinarenes at the air/water interface

Hybrid molecular floating films consisting of nematic liquid crystals (LC) and calix[4]resorcinarene (CRA: C11CRA and C19CRA) derivatives having amphiphilic nature are obtained on the water surface. CRA bearing four alkyl chains and eight carboxy groups at each rim of the macrocyclic skeleton has the ability to incorporate hydrophobic liquid crystalline molecules in their hydrophobic cavity to form homogeneous hybrid floating films. The molecular organization of liquid crystals in the hybrid films is affected by the length of alkyl residues of CRA. According to UV–vis absorption spectra, it was confirmed that liquid crystalline azobenzene (C6Azo) as a guest molecule form J-type aggregation with molecular orientation perpendicular to a water surface for the C6Azo/C11CRA system. On the other hand, C6Azo displays H-type aggregation with a perpendicular orientation for the system consisting of C19CRA as a host molecule.