Measurement of the Transition Temperature Governing the Photoinduced Reversible Solid-to-Liquid Transition of Azobenzene-Containing Polymers
Résumé
The ability to observe photoinduced reversible solid-to-liquid transitions for
some polymers bearing photo-active azobenzene groups (azopolymers) has become a
competitive research field in materials science and technology because of their potential
applications in photocontrolled adhesives, photohealable materials, or soft lithography.
Unfortunately, methods to accurately characterize this transition are scarce and mainly
qualitative, which limits the understanding of the parameters governing it. In the first part of
this paper, we will show that the photoinduced reversible solid-to-liquid transition can be
associated to a transition temperature (named TSL). This transition temperature can be
accurately measured using a scanning probe microscopy-based method. Then, the
measurement of TSL on azopolymers with different chemical structures will allow us to
understand why the experimental irradiation conditions to observe the solid-to-liquid
transition were different. With the possibility to accurately characterize the photoinduced
solid-to-liquid transition, we believe that this work paves the way to the optimization of
azopolymer design for a better photocontrol of their mechanical properties.