Kim Jae-Hyun, Hwang Hye Jeong, Oh Joon Suk, Sacanna Stefano, Yi Gi-Ra
School of Chemical Engineering , Sungkyunkwan University , Suwon 16419 , Republic of Korea.
J Am Chem Soc. 2018 Jul 25;140(29):9230-9235. doi: 10.1021/jacs.8b05128. Epub 2018 Jul 13.
A simple yet versatile solution-based process to produce colloidal silica hexapods is developed in which various shapes of silica rods are grown on the faces of cubes in a controlled manner. In the presence of hematite cubic particles, water droplets nucleate on the surface of hematite by phase separation in pentanol. By adjusting the water concentration, six droplets can form on each face of the hematite cube. A silica precursor is then administered into the system, which gradually diffuses into the water droplets through the oil phase. Within the droplets, hydrolysis and condensation of the precursors take place, leading to formation of silica rods. As a result, silica hexapods on a magnetic hematite cubic seed are produced. Furthermore, when the emulsions are aged at 60 °C prior to the silica growth, the water content in the solution decreases gradually due to evaporation and spiky sharp hexapods are produced. On the other hand, when organosilane precursor is added, pancake-like hexapods are formed due to the reduction of interfacial tension. These colloidal hexapods can further be utilized as new building blocks for self-assembly to construct functional materials or as a model system to understand collective behaviors.
开发了一种简单但通用的基于溶液的方法来制备胶体二氧化硅六足体，其中各种形状的二氧化硅棒以可控方式生长在立方体的面上。在赤铁矿立方颗粒存在的情况下，水滴通过在戊醇中的相分离在赤铁矿表面成核。通过调节水的浓度，在赤铁矿立方体的每个面上可以形成六个水滴。然后将二氧化硅前驱体引入系统，它通过油相逐渐扩散到水滴中。在水滴内，前驱体发生水解和缩合，导致二氧化硅棒的形成。结果，在磁性赤铁矿立方种子上产生了二氧化硅六足体。此外，当乳液在二氧化硅生长之前于60℃老化时，由于蒸发，溶液中的含水量逐渐降低，并产生尖刺状的六足体。另一方面，当加入有机硅烷前驱体时，由于界面张力的降低会形成薄饼状的六足体。这些胶体六足体可以进一步用作自组装的新构建块来构建功能材料，或用作理解集体行为的模型系统。
