Looking for the glass transition in a single molecular layer on the water surface

We present here results which indicate that polymeric monolayers confined at the air–water interface may provide interesting model systems for the study of glass transition phenomenology in a strongly confined 2D geometry. We report on photoinduced relaxation of the pressure–area isotherms in Langmuir monolayers of a photosensitive polyacrylate, using null-ellipsometry to study the evolution of the film thickness in the neighbourhood of the bulk glass transition. Furthermore, viscoelastic behaviour is investigated by a combination of surface quasielastic light scattering and expansion–compression isothermal cycles.