Innovative\nSilica Acorn Core–Shell Nanostructures:\nMorphological Control and Applications in Chromatography

This study introduces the synthesis and characterization\nof advanced\nsilica core–shell nanostructures, with an emphasis on the innovative\nSi-ACS (Silica Acorn Core–Shell) design and its modified counterparts.\nEmploying the classic Stöber method, SiCore particles were\nfirst produced, followed by the creation of the acorn-like Si-ACS\nstructures. A key aspect of this research is the exploration of the\neffects of CTAB and TEOS concentrations on the morphology and properties\nof the silica shells. The study reveals that surfactant concentration\ninfluences shell morphology from corn-like to uniformly thin structures,\nas well as the shell thickness. Specifically, increasing the CTAB\nconcentration from 45.8 mM to 166.9 mM increased the silica shell\nthickness from 160 to 280 nm, demonstrating the significant impact\nof surfactant concentration on shell formation. Si-ACS particles exhibited\na surface area of 55.54 m<sup>2</sup>/g and a pore volume of 0.64\ncm<sup>3</sup>/g, as evidenced by BET measurements, indicating successful\nmesopore formation critical for catalytic and adsorption applications.\nThe materials were further modified with cholesterol and tetraethyl\npentaamine (TEPA), which was confirmed by FT-IR analysis. Additionally,\nthe study demonstrates the application of these functionalized nanostructures\nas chromatographic columns. In particular, the dual-mode interactions\nof Si-ACS-CHOL-TEPA significantly improve the separation of phthalate\nesters, thereby highlighting the potential of these materials in advanced\nanalytical and biotechnological applications.