Development of photocleavable block copolymers as precursors for functional nanomaterials

(eng) Block copolymers have become nowadays powerful tools for the preparation of nanostructured materials. They are indeed able to self-assemble at the nanoscale into well-ordered structures that can be used, for example, for the preparation of nanoporous materials by selectively removing the minor phase. These materials exhibit the pore topology and the pore size of their parent structures and can be further used as separation membranes or templates for other nanomaterials. Most methods reported up to now for the creation of nanopores rely on the degradation of the minor block and offer thus a rather poor control over the functionality of the pore walls. In this thesis, a new approach towards nanoporous materials displaying chemical functionalities has been investigated. The first step of the project was the synthesis of block copolymers containing one or several o-nitrobenzyl photocleavable moieties. After their synthesis, their behavior upon UV irradiation has been studied in solution in order to determine the optimal conditions for their photocleavage. Then, the different synthesized photocleavable block copolymers have been self-assembled in thin films presenting a cylindrical morphology and the conditions of annealing leading to the desired perpendicular orientation of the cylinders have been optimized. Finally the creation of porosity after irradiation and removal of the minor phase has been studied and demonstrated.