Principles of Hierarchical Meso- and Macropore Architectures by Liquid Crystalline and Polymer Colloid Templating.

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autorinnen und Autoren: Thommes M
Zeitschrift: Langmuir
Verlag: American Chemical Society
Jahr der Veröffentlichung: 2006
Band: 22
Heftnummer: 5
Seitenbereich: 2311-2322-2322
ISSN: 0743-7463
eISSN: 1520-5827


Abstract

The generation of porous SiO2 with hierarchically organized bimodal mesoporosity of adjustable size and well-defined shape was studied by using surfactant mixts. and the nanocasting procedure (liq. cryst. templating). A systematic study of combinations of various block copolymers (Pluronics F127, KLE (poly(ω-hydroxypoly(ethylene-co-butylene)-co-poly(ethylene oxide))) and SE (PS-co-PEO)) with smaller surfactants (Pluronics P123, C16mimCl, and CTAB) revealed that hierarchical bimodal mesopore architectures could only be obtained by the usage of block copolymers with a strong hydrophilic-hydrophobic contrast, such as KLE and SE, giving rise to pores between 6 and 22 nm. Also, the ionic liq. (IL) C16mimCl appeared to have advantageous templating properties, resulting in 2-3-nm pores being located between the block copolymer mesopores, whereas phase sepn. was obsd. for Pluronics and CTAB as small templates. Thereby, the study provided also general insights into the mixing and co-self-assembly behavior of block copolymers and ionic surfactants in H2O and confirmed the special templating properties of ILs, as recently proposed. In addn. to the bimodal mesoporosity, addnl. tunable macroporosity was created by the presence of poly(styrene) or poly(Me methacrylate) spheres, leading to well-defined trimodal hierarchical pore architectures with the small pores being located in the walls of the resp. larger pores. As a major improvement, due to the pore hierarchy, these large-pore materials showed relatively large surface areas and pore vols., and the size of densely packed macropores could even be decreased down to 90 nm. The materials were characterized by electron microscopy, small-angle x-ray scattering, and nitrogen sorption using a proper NLDFT (nonlocal d. functional theory) approach for calcns. of the pore size distribution in the entire range of micro- and mesopores. [on SciFinder(R)]


FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Thommes, Matthias Prof. Dr.
Lehrstuhl für Thermische Verfahrenstechnik

Zuletzt aktualisiert 2019-23-08 um 09:18