Lin Zhen, Haataja Johannes S, Hu Xichen, Hong Xiaodan, Ikkala Olli, Peng Bo
Department of Applied Physics, Aalto University, P.O. Box 15100, 02150 Espoo, Finland.
Department of Materials Science, Advanced Coatings Research Center of Ministry of Education of China, Fudan University, Shanghai 200433, China.
Cell Rep Phys Sci. 2024 Jun 19;5(6):102021. doi: 10.1016/j.xcrp.2024.102021.
In colloids, the shape influences the function. In silica, straight nanorods have already been synthesized from water-in-oil emulsions. By contrast, curly silica nanofibers have been less reported because the underlying growth mechanism remains unexplored, hindering further morphology control for applications. Herein, we describe the synthetic protocol for silica nanofibers with a tunable curliness based on the control of the water-in-oil emulsion droplets. Systematically decreasing the droplet size and increasing their contact angle, the Brownian motion of the droplets intensifies during the silica growth, thus increasing the random curliness of the nanofibers. This finding is supported by simplistic theoretical arguments and experimentally verified by varying the temperature to finely tune the curliness. Assembling these nanofibers toward porous disordered films enhances multiple scattering in the visible range, resulting in increased whiteness in contrast to films constructed by spherical and rod-like building units, which can be useful for, e.g., coatings and pigments.
在胶体中，形状影响功能。在二氧化硅中，直的纳米棒已经从油包水乳液中合成出来。相比之下，卷曲的二氧化硅纳米纤维报道较少，因为其潜在的生长机制仍未被探索，这阻碍了进一步的形态控制以用于实际应用。在此，我们描述了一种基于油包水乳液滴控制的具有可调卷曲度的二氧化硅纳米纤维的合成方案。通过系统地减小液滴尺寸并增大其接触角，在二氧化硅生长过程中液滴的布朗运动加剧，从而增加了纳米纤维的随机卷曲度。这一发现得到了简单理论论证的支持，并通过改变温度来微调卷曲度进行了实验验证。将这些纳米纤维组装成多孔无序薄膜可增强可见光范围内的多次散射，与由球形和棒状构建单元构成的薄膜相比，会使白度增加，这可用于例如涂料和颜料等领域。
