Towards mesoporous Keggin-type polyoxometalates –systematic study on organic template removal
Lunkenbein, T. ; Kamperman, M.M.G. ; Schieder, M. ; With, S. ; Li, Z. ; Sai, H. ; Forster, S. ; Wiesner, U. ; Breu, J. - \ 2013
Journal of Materials Chemistry. A, Materials for energy and sustainability 1 (2013). - ISSN 2050-7488 - p. 6238 - 6248.
transition-metal oxides - catalytic-properties - building-blocks - acid catalysts - silica - molybdenum - mesostructures - nanocomposite - architectures - tungsten
Here, we present systematic studies on the removal of the polymer template from inverse hexagonally ordered poly(butadiene-block-2-dimethylaminoethyl methacrylate)–phosphomolybdic acid (H3PMo12O40) nanocomposites. Highly ordered mesophases are obtained via an evaporation-induced self-assembly process. Different techniques are used to remove the organic template: direct calcination in air, a two-step heat treatment ((1) argon atmosphere and (2) oxidative atmosphere), and a combination of heat and plasma treatment. Our studies show that direct calcination in air and two-step heat treatment lead to a collapse of mesostructure before complete carbon removal is accomplished. In contrast, plasma etching of heat treated ultra-microtomed samples results in hexagonally ordered porous nanofilms
Nanomanufacturing of continuous composite nanofibers with confiment-induced morphologies
Kamperman, M.M.G. ; Korley, L.T.J. ; Yau, B. ; Johansen, K.M. ; Joo, Y.L. ; Wiesner, U. - \ 2010
Polymer Chemistry 1 (2010)7. - ISSN 1759-9954 - p. 1001 - 1004.
block-copolymer nanofibers - styrene triblock copolymer - high-temperature ceramics - lamellar morphology - electrospun fibers - diblock copolymers - diameter fibers - nanocomposites - mesostructures - microphase
Continuous core-shell nanofibers with poly(isoprene-block-dimethylaminoethyl methacrylate) (PI-b-PDMAEMA) block copolymer/polymer derived ceramic (PDC) precursor nanocomposites as cores enveloped in rigid polyacrylonitrile (PAN) shells were nanomanufactured using coaxial electrospinning. The cylindrical confinement imposed by the rigid shell led to ordered morphologies in the core not observed in bulk block copolymer nanocomposites.
Morphology diagram of a diblock copolymer - aluminosilicate nanoparticle system
Garcia, B.C. ; Kamperman, M.M.G. ; Ulrich, R. ; Jain, A. ; Gruner, S.M. ; Wiesner, U. - \ 2009
Chemistry of materials 21 (2009)22. - ISSN 0897-4756 - p. 5397 - 5405.
mesoporous molecular-sieves - block-copolymer - plumbers nightmare - bicontinuous phases - hybrid materials - direct access - silica - oxide - mesostructures - crystalline
We explore the morphology space of nanocomposites prepared from poly(isoprene-block-ethylene oxide) (PI-b-PEO) diblock copolymers as structure directing agents for aluminosilicate nanoparticles prepared from (3-glycidyloxypropyl)trimethoxysilane (GLYMO) and aluminum(III) sec-butoxide. The results of structural investigations of over 60 polymer-inorganic nanocomposites are reported. They are obtained from 12 different block copolymers of varying molecular weight (10-100 kg/mol) and PEO weight fraction (fw 0.1-0.8) through addition of different amounts of inorganic components. Eight different morphologies as well as composites with biphasic character are observed. Individual block copolymers show up to five different well-defined morphologies upon addition of the inorganic sols. Differential scanning calorimetry (DSC) studies on the composites show that the addition of the inorganic components suppresses PEO crystallization when the inorganic to PEO weight fraction ratio of the composites is greater than 1.3-1.5. The eight phases are mapped out using two- and three-component morphology diagrams.