Lu Jun, Zhao Xiaopeng
Institute of Electrorheological Technology, Department of Applied Physics 141, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China.
J Colloid Interface Sci. 2004 May 15;273(2):651-7. doi: 10.1016/j.jcis.2004.02.066.
Poly-N-methaniline/montmorillonite (PNMA-MMT) nanocomposite particles with high dielectric constant as well as suitable conductivity were synthesized by an emulsion intercalation method and characterized by FT-IR, XRD, and TEM spectrometry, respectively. The electrorheological (ER) properties of the suspensions of PNMA-MMT particles in silicone oil (20 wt%) were investigated under DC electric fields. It was found that the shear stress of poly-N-methaniline/montmorillonite electrorheological fluid (ERF) is 6.0 kPa in 3 kV/mm (74.5 s(-1)), which is 3.6 times that of electrorheological fluid at zero field, and also much higher than that of pure poly-N-methaniline (PNMA) and montmorillonite (MMT). In the range of 10-90 degrees C, the shear stress changes slightly with the temperature. The sedimentation ratio of PNMA-MMT ERF was about 97% after 60 days. Furthermore, the dielectric constant of PNMA-MMT nanocomposite was increased 3.74 times that of PNMA and 1.99 times that of MMT at 1000 Hz, the dielectric loss tangent also increased about 1.58 times that of PNMA. It is apparent that the notable ER effect of PNMA-MMT ER fluid was attributed to the prominent dielectric property of the poly-N-methaniline/montmorillonite nanocomposite particles.
采用乳液插层法合成了具有高介电常数和合适电导率的聚-N-苯胺/蒙脱土（PNMA-MMT）纳米复合颗粒，并分别通过傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）和透射电子显微镜（TEM）光谱对其进行了表征。研究了PNMA-MMT颗粒在硅油（20 wt%）中的悬浮液在直流电场下的电流变（ER）性能。结果发现，聚-N-苯胺/蒙脱土电流变液（ERF）在3 kV/mm（74.5 s(-1)）时的剪切应力为6.0 kPa，是零场下电流变液的3.6倍，也远高于纯聚-N-苯胺（PNMA）和蒙脱土（MMT）。在10-90℃范围内，剪切应力随温度变化不大。PNMA-MMT ERF在60天后的沉降率约为97%。此外，PNMA-MMT纳米复合材料在1000 Hz时的介电常数比PNMA提高了3.74倍，比MMT提高了1.99倍，介电损耗角正切也比PNMA增加了约1.58倍。显然，PNMA-MMT ERF显著的电流变效应归因于聚-N-苯胺/蒙脱土纳米复合颗粒突出的介电性能。
