Sol-Gel-Controlled Size and Morphology of Mesoporous Silica Microspheres Using Hard Templates

Julia C Steinbach; Fabio Fait; Hermann A Mayer; Andreas Kandelbauer

doi:10.1021/acsomega.3c03098

Sol-Gel-Controlled Size and Morphology of Mesoporous Silica Microspheres Using Hard Templates

ACS Omega. 2023 Aug 9;8(33):30273-30284. doi: 10.1021/acsomega.3c03098. eCollection 2023 Aug 22.

Authors

Julia C Steinbach^{1

2}, Fabio Fait^{1

2}, Hermann A Mayer², Andreas Kandelbauer^{1

3}

Affiliations

¹ Process Analysis & Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstraße 150, Reutlingen 72762, Germany.
² Institute of Inorganic Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany.
³ Institute of Wood Technology and Renewable Materials, Department of Material Sciences and Process Engineering (MAP), University of Natural Resources and Life Sciences, Gregor-Mendel-Straße 33, Vienna 1180, Austria.

Abstract

Mesoporous silica microspheres (MPSMs) represent a promising material as a stationary phase for HPLC separations. The use of hard templates provides a preparation strategy for producing such monodisperse silica microspheres. Here, 15 MPSMs were systematically synthesized by varying the sol-gel reaction parameters of water-to-precursor ratio and ammonia concentration in the presence of a porous p(GMA-co-EDMA) polymeric hard template. Changing the sol-gel process factors resulted in a wide range of MPSMs with varying particle sizes from smaller than one to several micrometers. The application of response surface methodology allowed to derive quantitative predictive models based on the process factor effects on particle size, pore size, pore volume, and specific surface area of the MPSMs. A narrow size distribution of the silica particles was maintained over the entire experimental space. Two larger-scale batches of MPSMs were prepared, and the particles were functionalized with trimethoxy(octadecyl) silane for the application as stationary phase in reversed-phases liquid chromatography. The separation of proteins and amino acids was successfully accomplished, and the effect of the pore properties of the silica particles on separation was demonstrated.