Hybrid Langmuir and LB Films Composed of Amphiphilic Cyclodextrins and Hydrophobic Azobenzene Derivatives

ABSTRACT

Hybrid Langmuir and LB films consisting of amphiphilic cyclodextrins (CDs) and hydrophobic azobenzenes (AZOs) were fabricated. Due to the larger cross-sectional area of the CD core compared with the sum of the cross-sectional areas of the attached alkyl chains, Langmuir and LB films composed of CD have free space in the hydrophobic regions. AZOs having hydrocarbon terminal chains were accommodated in the free space. The average tilt angles of AZO(p-Hexyl) gave minima when the free space was just filled with the AZO. On the other hand, AZO(p-oxy) maintained perpendicular orientation even when the sum of the cross-sectional areas of AZO(p-oxy) exceeded the size of the free space.

Keywords:

• azobenzene
• cross-sectional area
• cyclodextrin, photoisomerization
• π-A isotherm

Acknowledgments

We wish to acknowledge Emeritus Professor W. Tagaki, Osaka City University for providing CDs.