2021 Volume 57 Issue 9 Pages 370-375
Some of azobenzene-based low-molecular-weight compounds and polymers exhibit reversible solid–liquid
phase transition upon UV and visible light irradiation. Such materials possess multi-azobenzene side chains
connected to their backbone with relatively long methylene spacer, and thus, upon UV irradiation, the material
with cis-azobenzene moiety become liquid due to its glass transition temperature below room temperature.
The phase transition materials can be used for reversible adhesives that can bond and debond two substrates
on demand. The photochemical process has unique features such as athermal, contactless, and spatio-seletive
activation, although the one of the two substrates must penetrate irradiating light. In this review, azobenzenebased
solid–liquid phase transition materials are reported with a focus on the relationship among the chemical
structure, solid–liquid phase transition behavior, and reversible adhesive ability.
