Photoinduced Liquefaction of Azobenzene-Containing Polymers

Light can liquefy some solid azobenzene-containing polymers (azopolymers) by photoisomerization. Two types of photoinduced liquefaction of azopolymers have been reported: (1) polarized light can guide solid azopolymers "flow" along the polarization direction, which is called directional photofluidization and has been used for inscription of surface relief gratings (SRGs); (2) recently, some of us found that light can switch the glass transition temperatures (T_g ) of azopolymers and induce reversible solid-to-liquid transitions of these azopolymers. This Minireview demonstrates and compares directional photofluidization and photoinduced reversible solid-to-liquid transitions of azopolymers. Potential applications based on photoinduced liquefaction of azopolymers are highlighted and some remaining challenges in the field of photoinduced liquefaction of azopolymers are discussed.