Fundamentals of tri-block copolymer self-assembly in solutions, and its relation to nano-templating

Abstract

The purpose of this thesis is to obtain a better understanding of the formation mechanism of mesoporous silica materials, such as SBA-15 that use block copolymers as templating agents. Despite the fact that these materials are now extensively synthesized, the fundamental role of the different synthesis variables has not been determined on the basis of a detailed physical chemical study. Such a synthesis typically starts with the formation of spherical micelles that are converted into long cylindrical micelles during silica hydrolysis and condensation. As a result, a silica matrix with hexagonally ordered mesopores is obtained, after removing the micelles by extraction or calcination. The interactions between the block copolymer and the various additives (silica, acids, salts, solvents) during the first steps of the synthesis in solution are believed to play an important role in the creation of these highly structured materials. Therefore, the emphasis of this thesis lays on providing fundamental information on the self-assembly process of the tri-block copolymer P123 (EO20PO70EO20), typically used in the synthesis of SBA-15, at conditions that mimic those of mesoporous materials synthesis as closely as possible.DelftChemTechApplied Science