Fluidization and dynamic heterogeneity induced by molecular motor’s stimuli in soft matter

When embedded inside soft matter, molecular motors induce stimuli that can result in a modification of the physical characteristics of the embedding medium. In azobenzene containing materials for example, a fluidization of the medium has been reported by several groups upon activation of the photo-isomerizing molecule. We discuss here the relations between the fluidization induced by small stimuli in amorphous materials and the glass-transition long standing problem. We focus our attention on the most important characteristic of the glass-transition, the spontaneous appearance of cooperative motions called dynamic heterogeneity that are thought to control the dynamics of the medium. We discuss how motors stimuli create dynamic heterogeneity from a cage-breaking mechanism, the properties of these heterogeneities and their relations with the observed fluidization.