Al-Khafaji Mohammed A, Gaál Anikó, Jezsó Bálint, Mihály Judith, Bartczak Dorota, Goenaga-Infante Heidi, Varga Zoltán
Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, H-1117 Budapest, Hungary.
Hevesy György Ph.D. School of Chemistry, Eötvös Loránd University, H-1117 Budapest, Hungary.
Nanomaterials (Basel). 2022 Apr 1;12(7):1172. doi: 10.3390/nano12071172.
Porous hollow silica particles possess promising applications in many fields, ranging from drug delivery to catalysis. From the synthesis perspective, the most challenging parameters are the monodispersity of the size distribution and the thickness and porosity of the shell of the particles. This paper demonstrates a facile two-pot approach to prepare monodisperse porous-hollow silica particles with uniform spherical shape and well-tuned shell thickness. In this method, a series of porous-hollow inorganic and organic-inorganic core-shell silica particles were synthesized via hydrolysis and condensation of 1,2-bis(triethoxysilyl) ethane (BTEE) and tetraethyl orthosilicate (TEOS) in the presence of hexadecyltrimethylammonium bromide (CTAB) as a structure-directing agent on solid silica spheres as core templates. Finally, the core templates were removed via hydrothermal treatment under alkaline conditions. Transmission electron microscopy (TEM) was used to characterize the particles' morphology and size distribution, while the changes in the chemical composition during synthesis were followed by Fourier-transform infrared spectroscopy. Single-particle inductively coupled plasma mass spectrometry (spICP-MS) was applied to assess the monodispersity of the hollow particles prepared with different reaction parameters. We found that the presence of BTEE is key to obtaining a well-defined shell structure, and the increase in the concentration of the precursor and the surfactant increases the thickness of the shell. TEM and spICP-MS measurements revealed that fused particles are also formed under suboptimal reaction parameters, causing the broadening of the size distribution, which can be preceded by using appropriate concentrations of BTEE, CTAB, and ammonia.
多孔空心二氧化硅颗粒在从药物递送催化等许多领域都有广阔的应用前景。从合成角度来看，最具挑战性的参数是尺寸分布的单分散性以及颗粒壳层的厚度和孔隙率。本文展示了一种简便的两步法来制备具有均匀球形且壳层厚度可调的单分散多孔空心二氧化硅颗粒。在该方法中，以十六烷基三甲基溴化铵（CTAB）作为结构导向剂，在固体二氧化硅球作为核模板的存在下，通过1,2 - 双（三乙氧基硅基）乙烷（BTEE）和正硅酸乙酯（TEOS）的水解和缩合反应，合成了一系列多孔空心无机和有机 - 无机核壳二氧化硅颗粒。最后，在碱性条件下通过水热处理去除核模板。使用透射电子显微镜（TEM）来表征颗粒的形态和尺寸分布，而在合成过程中化学成分的变化则通过傅里叶变换红外光谱进行跟踪。应用单颗粒电感耦合等离子体质谱（spICP - MS）来评估用不同反应参数制备的空心颗粒的单分散性。我们发现BTEE的存在是获得明确壳层结构的关键，并且前驱体和表面活性剂浓度的增加会增加壳层的厚度。TEM和spICP - MS测量表明，在次优反应参数下也会形成融合颗粒，导致尺寸分布变宽，而通过使用适当浓度的BTEE、CTAB和氨可以避免这种情况。
