NMR Studies on Silica Monoliths - Diffusion in a Hierarchical Pore Structure
نویسندگان
چکیده
1. Introduction For many applications in chromatography and separation, porous materials with a structure-in-structure fashion are desirable. For such applications, silica monoliths were synthesized which have a trimodal, hierarchical pore structure [1]. It consists of three different interconnected pore domains with pore diameters (measured by Hg-porosimetry) in the range of a few microns (macropores), 18 nm and about 2-3 nm (mesopores and micropores). In this study, we investigated transverse relaxation times (T 2) and self-diffusion of methanol, benzene and water (loadings: 25%, 50%, 90-100% pore filling) in two silica monoliths, which differ mainly in the diameter of their macropores (JHS-002-02 d JHS =3 μm; CL-14, d CL =24 μm).
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