Pyrrole-Containing ABA Triblock Brush Polymers as Dual Functional Molecules to Facilely Access Diverse Mesostructured Materials

We report a new type of ABA-type brush-like triblock copolymer (PEGMA-b-PPHMA-b-PEGMA), which is characterized by two hydrophilic end segments (A) and a hydrophobic midblock (B) bearing polymerizable pyrrole moieties. This kind of symmetric triblock copolymers can not only serve as a structure-directing agent for the formation of mesoporous silicates but also function as a polymerizable monomer or carbon source for further chemical conversion to deliver mesostructured polymer or carbon materials within the preformed silicate framework. By utilizing such dual functional macromolecules, rich morphologies of mesostructures are accessible through microphase separation, and the order-order transition among cubic, lamellar, 2D hexagonal, and bicontinuous mesostructures is sensitively achievable by varying the hydrophilic volume fraction of copolymers and TEOS dosage. These features enable facile access to diverse mesostructured silica, polymer, and carbon materials. Remarkably, due to the brush-like polymer architecture and the formation of loop configuration, a widely tunable pore size from mesoscale to macroscale is realizable through using a relatively lower molecular weight copolymer. Importantly, it is found that the brush-like hydrophilic segments of our triblock copolymers can firmly anchor into the silica walls without appreciable escape of copolymer template in commonly used solvents even under reflux extraction, providing a prerequisite for reliable confined chemical transformation into mesostructured polymer and carbon materials. Our work demonstrates that the design and synthesis of functional amphiphilic block copolymers will bring great opportunity for the development of novel mesostructured materials.