Kowalewska Anna, Majewska-Smolarek Kamila, Herc Agata S, Kaźmierski Sławomir, Bojda Joanna
Department of Polymeric Nano-Materials, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Łódź, Poland.
Department of Structural Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Łódź, Poland.
Materials (Basel). 2025 Jul 17;18(14):3357. doi: 10.3390/ma18143357.
The interest in macromolecular alkoxysilyl-functionalized hybrids (self-assembling or nanostructured), which could be used as precursors in biomimetic silica precipitation and for the synthesis of hollow spherical silica particles, is growing. Nevertheless, reports on all-organosilicon systems for bioinspired silica precipitation are scarce. Therefore, a new kind of polyalkoxysilane macromonomer-linear polysilsesquioxane (LPSQ) of ladder-like backbone, functionalized in side chains with trimethoxysilyl groups (LPSQ-R-Si(OMe)), was designed following this approach. It was obtained by photoinitiated thiol-ene addition of 3-mercaptopropyltrimethoxysilane to the vinyl-functionalized polysilsesquioxane precursor, carried out in situ in tetraethoxysilane (TEOS). The mixture of LPSQ-R-Si(OMe) and TEOS (co-monomers) was used in a sol-gel process conducted under acidic conditions (0.5 M HCl/NaCl) in the presence of Pluronic F-127 triblock copolymer as a template. LPSQ-R-Si(OMe) played a key role for the formation of microparticles of a spherical shape that were formed under the applied conditions, while their size (as low as 3-4 µm) was controlled by the stirring rate. The hybrid materials were hydrophobic and showed good thermal and oxidative stability. Introduction of zinc acetate (Zn(OAc)) as an additive in the sol-gel process influenced the pH of the reaction medium, which resulted in structural reinforcement of the hybrid microparticles owing to more effective condensation of silanol groups and a relative increase of the content of SiO. The proposed method shows directions in designing the properties of hybrid materials and can be translated to other silicon-organic polymers and oligomers that could be used to produce hollow silica particles. The established role of various factors (macromonomer structure, pH, and stirring rate) allows for the modulation of particle morphology.
对可作为仿生二氧化硅沉淀前体及用于合成空心球形二氧化硅颗粒的大分子烷氧基硅官能化杂化物（自组装或纳米结构）的兴趣与日俱增。然而，关于用于受生物启发的二氧化硅沉淀的全有机硅体系的报道却很少。因此，按照这种方法设计了一种新型的聚烷氧基硅烷大分子单体——具有梯状主链且侧链被三甲氧基硅基官能化的线性聚倍半硅氧烷（LPSQ-R-Si(OMe)）。它是通过在四乙氧基硅烷（TEOS）中原位进行3-巯基丙基三甲氧基硅烷与乙烯基官能化聚倍半硅氧烷前体的光引发硫醇-烯加成反应而制得的。LPSQ-R-Si(OMe)和TEOS（共聚单体）的混合物在酸性条件（0.5 M HCl/NaCl）下，以Pluronic F-127三嵌段共聚物为模板进行溶胶-凝胶过程。LPSQ-R-Si(OMe)对于在所施加条件下形成的球形微粒的形成起到关键作用，而其尺寸（低至3 - 4 µm）由搅拌速率控制。这些杂化材料具有疏水性，并且表现出良好的热稳定性和氧化稳定性。在溶胶-凝胶过程中加入醋酸锌（Zn(OAc)）作为添加剂会影响反应介质的pH值，这由于硅醇基团更有效的缩合以及SiO含量的相对增加而导致杂化微粒的结构增强。所提出的方法为设计杂化材料的性能指明了方向，并且可以推广到其他可用于制备空心二氧化硅颗粒的硅有机聚合物和低聚物。各种因素（大分子单体结构、pH值和搅拌速率）所确定的作用使得能够调节颗粒形态。
