聚甲基丙烯酸甲酯（PMMA）中PDMS纳米尺寸污染的鉴定检测方案(红外光谱仪)

Nano-FTIR absorption spectroscopy of molecularfingerprints at 20 nm spatial resolution Florian Huth’， Alexander Govyadinov'，Sergiu Amarie’， Wiwat Nuansing， Fritz Keilmann ， and Rainer Hillenbrand 5* CIC nanoGUNE Consolider， 20018 Donostia-San Sebastián， SpainNeaspec GmbH， 82152 Martinsried， Germany Max Planck Institute of Quantum Optics， 85714 Garching， Germany "Department of Physics and CeNS， Ludwigs-Maximilians-Universitat Munchen， 85714Garching， Germany 'IKERBASQUE， Basque Foundation for Science， 48011 Bilbao， Spain *corresponding author email： r.hillenbrand@nanogune.eu SUPPLEMENTAL MATERIAL Relation between Im[B(w)]and K(w). In order to demonstrate the correlation between Im[f(w)] and k we express both in terms of thelocal dielectric function e(ω)=81 +ie2 of the sample： where B=8-1Equation S2 follows from N = n +ik=√e. In Fig. S1 we plot Im[B] and K as afunction of frequency w for PMMA， a typical weak molecular oscillator. To that end， we use realand imaginary parts of e(w) obtained from ellipsometry measurements. The correspondencebetween the spectra can be clearly seen. Fig. S1. The spectra of k (black) and Im[B] (red) for a PMMA sample calculated from the realand imaginary parts of e(w) obtained by ellipsometry. Both spectra are normalized to the peakvalues at ω≈1730cm-1. Reconstruction of K from the near-field absorption an From the measured near-field absorption an we can obtain k through the relation K=C·Im[B]， le+1|2where C =， which directly follows from Eqs. (S1-S2). The factor C can， in principle， be4Refound directly by determining e from near-field measurements of on as discussed below Eq. (3) of the main article. 本文展示了纳米傅立叶红外光谱技术（nano-FTIR）的可行性和实验结果。nano-FTIR是将散射型近场光学显微镜与宽带红外激光光源整合获得的。测试结果显示nano-FTIR可以对有机材料获得20nm空间分辨率的红外吸收光谱，实际测量样品体积只相当于10-20L，理论上讲，nano-FTIR吸收光谱与传统FTIR吸收光谱吻合度极高，而实验中对PMMA样品的测试也证明了这一点。因此nano-FTIR可以利用标准分子震荡红外数据库来对极小量需要极高空间分辨率的有机材料进行化学鉴定。本文中以对PMMA样品中的PDMS纳米尺寸污染的鉴定作为例证。使用nano-FTIR对纳米尺度污染物的化学鉴定。AFM表面形貌图像 (左), 在Si片基体（暗色区域Ｂ）与PMMA薄膜（Ａ）之间可以观察到一个小的污染物。机械相位图像中（中），对比度变化证明该污染物的是有别于基体和薄膜的其他物质。将点Ａ和Ｂ的nano-FTIR 吸收光谱（右），与标准红外光谱数据库对比， 获得各部分物质的化学成分信息. 每条谱线的采集时间为7min, 光谱分辨率为13 cm-1。参考文献：Huth F , Govyadinov A , Amarie S , et al. Nano-FTIR Absorption Spectroscopy of Molecular Fingerprints at 20 nm Spatial Resolution[J]. Nano Letters, 2012, 12(8):3973-3978.