Curing Induced Structural Reorganization and Enhanced Reactivity of Amino-Terminated Organic Thin Films on Solid Substrates: Observations of Two Types of Chemically and Structurally Unique Amino Groups on the Surface
Curing Induced Structural Reorganization and Enhanced Reactivity of Amino-Terminated Organic Thin Films on Solid Substrates: Observations of Two Types of Chemically and Structurally Unique Amino Groups on the Surface
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DOI：
10.1021/la2007205
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发表时间：
2011-05-03
期刊：
影响因子：
3.9
通讯作者：
Somorjai, Gabor A.
中科院分区：
文献类型：
--
作者：
Kim, Joonyeong;Holinga, George J.;Somorjai, Gabor A.
首次采用可见-可见和频振动光谱（SFG）研究了在可控实验条件下沉积在固体基底上的3-氨丙基三乙氧基硅烷（APTES）薄膜的结构。我们的SFG光谱与互补的分析数据相结合，表明APTES薄膜在高温下固化时发生结构变化。在膜固化之前，有序的疏水乙氧基主要存在于表面上。大多数亲水性表面氨基被质子化，并且它们在界面处被掩埋或随机取向。在膜固化后，在表面上检测到化学和结构不同的中性氨基。与质子化氨基不同，一类新的中性氨基在界面处有序，并显示出增强的反应活性。
Infrared-visible sum frequency generation vibrational spectroscopy (SFG) was used to characterize the structure of 3-amino-propyltriethoxysilane (APTES) films deposited on solid substrates under controlled experimental conditions for the first time. Our SFG spectra in combination With complementary analytical data showed that APTES films undergo structural changes when cured at an elevated temperature. Before the films are cured, well-ordered hydrophobic ethoxy groups are dominantly present on the surface. A majority of hydrophilic surface amino groups are protonated, and they are either buried or randomly oriented at the interface. After the films are cured, chemically and structurally different neutral amino groups are detected on the surface. Unlike the protonated amino groups, a new class of neutral amino groups is ordered at the interface and shows enhanced reactivity.