7. Other applications

7.1 Controlled hydrophobicity, object movement

Azobenzenes are particularly popular as light-sensitive chromophores, and so many light-sensitive surfaces composed of azobenzenes have been investigated. In 2005, a simple electrostatic self-assembly technique was used to fabricate a photocommutating azobenzene monolayer on rough surfaces, for which superhydrophobicity appeared, and a reversible change in contact angles from 78.3° to 152.6°, i.e. 33 times greater than that of a flat film, was achieved by irradiating UV and visible light by introducing geometric structures (square pillars) on the substrate surface. Based on the trans-cis isomerization of azobenzene, a photocontrolled molecular shuttle composed of an α-cyclodextrin/azobenzene structure on raw gold surfaces was fabricated,...