Adaptive materials for optical applications: Example of the polymer/liquid crystal micro-composites

We will present an overview of the different polymer/liquid crystal microcomposites and their use for the control of the optical flux. The preparation method is the key element of this generic family of materials. There is a great number of pertinent parameters (relative concentration of constituents, irradiation. conditions,...) acting on the morphology and therefore on the final properties. Materials with very different electro-optical properties can be obtained. We will first discuss the case where the spatial repartition of heterogeneity is uniform in the sample : light occlusion films (with direct or reverse mode, selective reflection films, films with optical bistability). The cholesteric films will be particularly emphasized. We will focus on the relation between the preparation, the electro-optical properties and the colorimetric properties of the films. Next, the effect of introducing a gradient in some parameters (as irradiation,...) influencing the material will be discussed. The use of these electrically controllable materials in adaptive optical materials for some applications such as optical components, smart windows, laser protection... will be reviewed.