Synthesis of an original oxazoline based monomer containing a photosensitive azobenzene moiety and investigation of the behavior in solid state, in aqueous and vapor media of a photo and thermo-responsive polyoxazoline copolymer

In this paper, the synthesis of original thermo-sensitive polyoxazoline copolymers, also containing photo-sensitive azobenzene moieties is reported. An original oxazoline monomer containing an azobenzene moiety is first synthesized and then engaged in CROP copolymerization with 2-isopropyl-2-oxazoline. Copolymers with different ratio of azobenzene moieties are then fully characterized. The presence of azobenzene moieties clearly increases the glass transition temperature and decreases the cloud point temperature of the resulting copolymers due to their hydrophobicity. The presence of azobenzene moieties also influences the water uptake capacity of the copolymers. It is also demonstrated that the presence of a few azobenzene moieties increases the water sorption of the copolymer compared to a comparable polyoxazoline homopolymer. Finally, the trans-cis isomerization of the azobenzene moieties under UV radiation is used to tune different properties of the final copolymers such as the glass transition temperature in solid state, the cloud point temperature in aqueous media and the water uptake capacity in vapor state. Thus, thanks to this new photo-sensitive copolymer, it is possible to easily tune various properties with a simple light radiation which can be useful for various applications.

Automated summary

In this study, thermo-sensitive polyoxazoline copolymers containing photo-sensitive azobenzene moieties were synthesized. The presence of azobenzene moieties significantly affected the properties of the resulting copolymers, including the glass transition temperature, cloud point temperature, and water uptake capacity. UV radiation-induced trans-cis isomerization of the azobenzene moieties allowed for the tuning of these properties. This photo-sensitive copolymer has great potential for various applications.