| Self-assembling approach is an essential technique to constructmicro/nanostructures, which are applicable to a range of disciplines, suchas physics, material science, chemistry and biological science. Blockcopolymers (BCPs) exhibit numerous phase behaviors in bulk and solutionand yield ordered structures in a wide range of morphologies. Therefore,they has attracted considerable attraction in the synthesis of novelinorganic micro/nanomaterial. Ordered mesoporous materials are a familyof porous materials containing uniform pore sizes ranging from2to50nm,which are prepared through self-assembling of amphiphic moleculars andcondensation of inorganic species. Exceptional properties of their highlyordered mesostructures, i.e. tunable pore size, large specific surface areaand pore volume endow them with powerful properties with countlessapplication in adsorption and separation, catalysis, biomedicine, optics andenergy storage. BCPs possess great flexibility because of their outstandingdesignability according to numerous pratical requirements. BCPself-assembly promises to become a powerful tool for the fabrication ofmesoporous materials with abundant mesostructures and tunable pore sizeand volume, which is excellent and interesting compared to the traditionalsmall-molecular templating method.In this work, we designed a novel triblock copolymer,polyethylene-block-poly (ethylene oxide)-block-polycaprolactone, whichwas denoted as PE-b-PEO-b-PCL. It was an amphiphilic polymer moleculecomposed of two hydrophobic blocks, PE and PCL, which are bothcrystalline polymers. Futhermore, the high degree of imcompatibility between PE and PCL block, which is specified by Flory-Hugginsparameter (χ), lead to the proceeding of their phase separation. Herein, weprepared various mesoporous silica materials with different morphologiesand structures templated by the designable triblock copolymers. Besides,the self-assembling phase behaviors and the structural transformationmechanisms in this fabrication process were investigated.In Chapter1, the related literatures and research background werereviewed as the following three aspects:(1) molecular self-assembly,(2)self-assembly of block copolymers and (3) an overview of mesoporousmaterials. The significance of this topic and research strategies were putforward based on these.In Chapter2, the PE-b-PEO-b-PCL triblock copolymers with differentblock ratios were synthesized through Ring-Opening Polymerization (ROP)process, in which hydroxyl terminated PE-b-PEO diblock copolymer andstannous octoate were used as the macromolecular initiator and catalyst,respectively.In Chapter3, mesoporous silica with highly order face-centered cubicstructure was prepared templated by PE13-b-PEO42-b-PCL19. It possessedWulff polyhedron morphology. PE and PCL block coexisted in thehydrophobic core of micelles, which could build the mesostructure jointly.Through adding the decane into the system, the pore size was enlarged andmeanwhile, multicore micelles were formed, which could direct two sets ofpore channels in one sample. Decreasing the chain length of PCL blockinduced the intergrowth of cubic and hexagonal crystal phases.In Chapter4, mesoporous silica with2-D hexagonal structure andcurving rod-like morphology was synthesized by the template ofPE20-b-PEO20-b-PCL10. The curving structure was attributed to thepressing from silica source through the interaction with the template. Theamount of silica source had an influence on the curving degree. Besides,the curving degree was lower when decreasing the chain length of PCLblock. Meanwhile, the pore structure exhibited a transformation trend from cylinder to cage-type, which could be explained by the theory ofg-parameter. |
