Mesoporous Silica Films with Long-Range Order Prepared from Strongly Segregated Block Copolymer/Homopolymer Blend Templates

Well-ordered mesoporous silica films were prepared by infusion and selective condensation of Si alkoxides within preorganized block copolymer/homopolymer blend templates using supercritical CO2 as the delivery medium. The morphologies of the mesoporous silica films reflect significant improvements in the strength of segregation and long-range order of template blends of poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) triblock copolymers with selectively associating homopolymers such as poly(acrylic acid) or poly(4-hydroxystyrene) prior as compared to templates comprised of the neat copolymer. Control over film porosity, pore ordering, and morphology of the films is achieved through simple variations in the homopolymer concentration. The films were characterized using X-ray reflectivity, small-angle X-ray scattering, and transmission electron microscopy.