ORIGINAL PAPER: NANO-STRUCTURED MATERIALS (PARTICLES, FIBERS, COLLOIDS, COMPOSITES, ETC.) Effects of different amounts of APTES on physicochemical and structural properties of amino-functionalized MCM-41-MSNs William Alejandro Talavera-Pech 1 • Adriana Esparza-Ruiz 1 • Patricia Quintana-Owen 2 • Alfredo Rafael Vilchis-Nestor 3 • Cristian Carrera-Figueiras 1 • Alejandro A ´ vila-Ortega 1 Received: 24 February 2016 / Accepted: 21 July 2016 Ó Springer Science+Business Media New York 2016 Abstract Mesoporous silica nanoparticles (MSNs) are frequently functionalized to be used for specific applica- tions, including catalysis and biomedical engineering. In this research, MCM-41-MSNs were synthesized by the sol– gel method and were functionalized with different quanti- ties of (3-aminopropyl) triethoxysilane (APTES) using a post-grafting method to determine the physicochemical and structural changes in the MSNs. The functionalized mate- rials were assessed by different characterization tech- niques, namely, TGA, FTIR, BET, SEM, TEM, DLS, zeta potential, SAXS, XRD and XPS. The FTIR data confirmed the presence of amino groups on the MSN surfaces, and the results from the XPS, TGA and zeta potential demonstrated that the APTES concentration during post-grafting directly affects the quantity of amino groups bound to the MSNs. The SAXS, TEM and nitrogen adsorption–desorption analyses showed that as the amount of APTES in the MSNs increases, the mesoporous structure become more disordered. Graphical Abstract Keywords Mesoporous silica nanoparticles Á Functionalization Á Amino Á Post-synthesis 1 Introduction High textural properties, mesoporous ordered structure, adjustable morphology, biocompatibility and ease of functionalization [1–3] are unique characteristics for MCM-41-type mesoporous silica nanoparticles (MSNs), which have been frequently studied in recent investigations for applications in heterogeneous catalysis [4], in the & Alejandro A ´ vila-Ortega alejandro.avila@correo.uady.mx 1 Faculty of Chemical Engineering, Universidad Auto ´noma de Yucata ´n (UADY), Perife ´rico Norte Km 33.5, 13615, Chuburna de Hidalgo Inn, 97203 Me ´rida, Yucata ´n, Me ´xico 2 Centro de Investigacio ´n y de Estudios Avanzados, Unidad Me ´rida, Antigua carretera a Progreso Km 6, Cordemex, 97310 Me ´rida, Yucata ´n, Me ´xico 3 Centro Conjunto de Investigacio ´n en Quı ´mica Sustentable, UAEM-UNAM, Km 14.5 Carretera Toluca-Atlacomulco, Toluca, Estado de Me ´xico, Me ´xico 123 J Sol-Gel Sci Technol DOI 10.1007/s10971-016-4163-4