Demonstrating the feasibility of monitoring the molecular-level structures of moving polymer/silane interfaces during silane diffusion using SFG
Demonstrating the feasibility of monitoring the molecular-level structures of moving polymer/silane interfaces during silane diffusion using SFG
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DOI：
10.1021/ja0390911
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发表时间：
2004-02-04
影响因子：
15
通讯作者：
Chen, Z
中科院分区：
文献类型：
--
作者：
Chen, CY;Wang, J;Chen, Z
在本文中，监测分子结构在一个移动的聚合物/液体界面的和频产生（SFG）振动光谱的可行性已被证明。将N-（2-氨乙基）-3-氨丙基三甲氧基硅烷（AATM，NH 2（CH 2）（2）NH（CH 2）（3）Si（OCH 3）（3））与氘代聚甲基丙烯酸甲酯（d-PMMA）膜接触，用SFG监测界面硅烷结构。在最初接触时，可以检测到SFG光谱，但随着时间的推移，光谱强度发生变化并最终消失。另外的实验表明，这些硅烷分子可以扩散到聚合物膜中，并且检测到的SFG信号实际上来自移动的聚合物/硅烷界面。我们的研究结果表明，在整个扩散过程中存在的聚合物/硅烷界面的分子秩序，并失去了当硅烷分子穿过d-PMMA膜的厚度。的SFG信号的损失是由于形成一个新的无序基板/硅烷界面，这有助于没有可检测的SFG信号。硅烷扩散到聚合物中的动力学已经从AATM分子扩散通过不同厚度的聚合物膜时检测到的时间依赖性SFG信号推导出。
In this paper, the feasibility of monitoring molecular structures at a moving polymer/liquid interface by sum frequency generation (SFG) vibrational spectroscopy has been demonstrated. N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (AATM, NH2(CH2)(2)NH(CH2)(3)Si(OCH3)(3)) has been brought into contact with a deuterated poly(methyl methacrylate) (d-PMMA) film, and the interfacial silane structure has been monitored using SFG. Upon initial contact, the SFG spectra can be detected, but as time progresses, the spectral intensity changes and finally disappears. Additional experiments indicate that these silane molecules can diffuse into the polymer film and the detected SFG signals are actually from the moving polymer/silane interface. Our results show that the molecular order of the polymer/silane interface exists during the entire diffusion process and is lost when the silane molecules traverse through the thickness of the d-PMMA film. The loss of the SFG signal is due to the formation of a new disordered substrate/silane interface, which contributes no detectable SFG signal. The kinetics of the diffusion of the silane into the polymer have been deduced from the time-dependent SFG signals detected from the AATM molecules as they diffuse through polymer films of different thickness.