Noh Jungchul, Yoon Chang-Min, Jang Jyongsik
School of Chemical and Biological Engineering, Seoul National University, 599 Gwanangro, Sillim-dong, Gwanak-gu, Seoul 151-742, Republic of Korea.
School of Chemical and Biological Engineering, Seoul National University, 599 Gwanangro, Sillim-dong, Gwanak-gu, Seoul 151-742, Republic of Korea.
J Colloid Interface Sci. 2016 May 15;470:237-244. doi: 10.1016/j.jcis.2016.02.061. Epub 2016 Mar 2.
Polyaniline-coated mesoporous silica (PANI/mSiO2) materials with different aspect ratios (L/D=1, 5, and 10) were fabricated by a vapor deposition polymerization (VDP) method to investigate the geometric effect on electrorheological (ER) activity. The PANI/mSiO2 materials were dedoped by a facile NH4OH treatment to reduce the conductivity to a level appropriate for ER applications. Notably, the PANI/mSiO2-based ER fluids exhibited enhanced ER performance with increasing aspect ratio. In particular, the PANI/mSiO2 material with the highest aspect ratio manifested the highest ER activity, which was attributed to geometric effects on flow resistance and mechanical stability. Moreover, the ER materials with higher aspect ratios showed improved dielectric properties of large achievable polarizability and short relaxation time. Hence, the synergistic contribution of geometric effects and dielectric properties resulted in enhanced ER activity. Consequently, this study provides insight into an effective method to improve ER performance by simple manipulation of the particle geometry.
通过气相沉积聚合（VDP）方法制备了具有不同纵横比（L/D = 1、5和10）的聚苯胺包覆介孔二氧化硅（PANI/mSiO2）材料，以研究几何形状对电流变（ER）活性的影响。通过简便的NH4OH处理对PANI/mSiO2材料进行去掺杂，将电导率降低到适合ER应用的水平。值得注意的是，基于PANI/mSiO2的电流变液随着纵横比的增加表现出增强的电流变性能。特别是，具有最高纵横比的PANI/mSiO2材料表现出最高的电流变活性，这归因于对流动阻力和机械稳定性的几何效应。此外，具有较高纵横比的电流变材料显示出具有大的可实现极化率和短弛豫时间的改善的介电性能。因此，几何效应和介电性能的协同作用导致电流变活性增强。因此，本研究为通过简单控制颗粒几何形状来提高电流变性能的有效方法提供了见解。
