CONTEXT

Azobenzen groups are known to exist under two isomeric conformations: either trans or cis.

The transition between this two conformations can be easily controllable through photoisomerization. Indeed, azobenzen groups are cis-conformed when exposed to Ultra-Violet light and trans-conformed when exposed to blue light (or after a long time under ambiant light).

Recently photosensitive surfactants containing an azobenzene group have been synthesized and have been shown to exhibit strong variations of the the surface tension upon cis-trans conversion.

Dispersions, especially foams and emulsions are difficult to stabilized. As a matter of consequence, their formation as well as their stabilization requires surfactants.

Unwanted dispersions appearing during a process are a very frequent issue in the industrial field. In order to counteract this unwanted issue, anti-foam agents or anti-emulsion agents are used but do not fully satisfy as they can’t be fully controlled and their action is not reversible. There is a current demand for an agent showing this property.