|Title:||Accessibility of amino groups in postsynthetically modified mesoporous silica|
|Authors :||Ritter, Hanna|
|Published in :||The Journal of Physical Chemistry Part C|
|Publisher / Ed. Institution :||American Chemical Society|
|License (according to publishing contract) :||Licence according to publishing contract|
|Type of review:||Peer review (Publication)|
|Subjects :||2009; ICBC; Mesopores; Accessibility|
|Subject (DDC) :||540: Chemistry|
|Abstract:||The accessibility of amino groups in postsynthetically functionalized mesoporous silica MCM-41, MCM-48, and SBA-15 is investigated by reaction with fluorescein isothiocyanate (FITC). The quantitative analysis of the surface-grafted amino groups in relation to the amount of coupled FITC over a wide range of loadings affords information about potential pore blocking. In the pore diameter domain of 3−4 nm, the actual pore size of materials with a one-dimensional channel system (MCM-41) strongly affects the FITC coupling yield and the distribution of the anchored fluorescein moieties. In the case of SBA-15 (7.6 nm pore diameter), the accessibility of the grafted amino groups is similar to what is expected for a material with a completely open surface. However, grafting in the intrawall micropores of SBA-15 leads to a substantial fraction of inaccessible amino groups. As a direct consequence of short channel lengths and large external surface area, excellent accessibility is also observed for nanometer-sized MCM-41 (3.2 nm pore diameter).|
|Departement:||Life Sciences und Facility Management|
|Organisational Unit:||Institute of Chemistry and Biotechnology (ICBT)|
|Publication type:||Article in scientific Journal|
|Appears in Collections:||Publikationen Life Sciences und Facility Management|
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