Longer Wavelength Azo Dyes for Incorporation in Photomechanical Polymer Networks | AIChE

Longer Wavelength Azo Dyes for Incorporation in Photomechanical Polymer Networks

Azo dyes have long been studied for their potential uses in photomechanical materials, which convert light energy directly into mechanical work for use as wireless actuators and switches. Most azo dyes undergo reversible trans to cis isomerization at ultraviolet to blue-green wavelengths. These comparatively high energy wavelengths are more prone to photodegrade materials or to be competitively absorbed by other components of a device or material, and they are incompatible with mammalian tissue. Thus, it is desirable to develop new azo-based photomechanical systems which absorb at lower energy wavelengths. Aprahamian and coworkers have reported BF2-coordinated azo dye analogs which undergo isomerization at orange-red to near infrared wavelengths. These longer wavelength dyes minimize photodegradation and competitive absorption and are more likely to be compatible with mammalian tissue. It is necessary to install polymerizable handles on these dyes if they may be incorporated into a photomechanical material. The synthesis of several dyes is reported.