Abbas S M, Dixit A K, Chatterjee R, Goel T C
Department of Physics, IIT Delhi, Hauz Khas, New Delhi 110016, India.
J Nanosci Nanotechnol. 2007 Jun;7(6):2129-33. doi: 10.1166/jnn.2007.782.
Polyaniline powder in nanosize has been synthesized by chemical oxidative route. XRD, FTIR, and TEM were used to characterize the polyaniline powder. Crytallite size was estimated from XRD profile and also ascertained by TEM in the range of 15 to 20 nm. The composite absorbers have been prepared by mixing different ratios of polyaniline into procured polyurethane (PU) binder. The complex permittivity (epsilon' - jepsilon") and complex permeability (mu' - jmu") were measured in X-band (8.2-12.4 GHz) using Agilent network analyzer (model PNA E8364B) and its software module 85071 (version 'E'). Measured values of these parameters were used to determine the reflection loss at different frequencies and sample thicknesses, based on a model of a single layered plane wave absorber backed by a perfect conductor. An optimized polyaniline/PU ratio of 3:1 has given a minimum reflection loss of -30 dB (99.9% power absorption) at the central frequency 10 GHz and the bandwidth (full width at half minimum) of 4.2 GHz over whole X-band (8.2 to 12.4 GHz) in a sample thickness of 3.0 mm. The prepared composites can be fruitfully utilized for suppression of electromagnetic interference (EMI) and reduction of radar signatures (stealth technology).
通过化学氧化法合成了纳米尺寸的聚苯胺粉末。采用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和透射电子显微镜（TEM）对聚苯胺粉末进行了表征。根据XRD图谱估算了微晶尺寸，TEM也确定其在15至20nm范围内。通过将不同比例的聚苯胺与采购的聚氨酯（PU）粘合剂混合制备了复合吸收剂。使用安捷伦网络分析仪（型号PNA E8364B）及其软件模块85071（版本“E”）在X波段（8.2 - 12.4GHz）测量了复介电常数（ε' - jε"）和复磁导率（μ' - jμ"）。基于单层平面波吸收体 backed by a perfect conductor的模型，利用这些参数的测量值来确定不同频率和样品厚度下的反射损耗。在3.0mm的样品厚度下，优化后的聚苯胺/PU比例为3:1时，在中心频率10GHz处的最小反射损耗为 - 30dB（功率吸收99.9%），在整个X波段（8.2至12.4GHz）的带宽（半高宽）为4.2GHz。所制备的复合材料可有效地用于抑制电磁干扰（EMI）和降低雷达信号特征（隐身技术）。 （注：原文中“backed by a perfect conductor”表述有误，应为“backed by a perfect electric conductor”，但按照要求未修改翻译。）
