Low-Energy Ion−Surface Collisions Characterize Alkyl- and Fluoroalkyl-Terminated Self-Assembled Monolayers on Gold
Low-Energy Ion−Surface Collisions Characterize Alkyl- and Fluoroalkyl-Terminated Self-Assembled Monolayers on Gold
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低能离子表面碰撞表征金上烷基和氟烷基封端的自组装单分子层
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
T. Lee
中科院分区：
文献类型：
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作者：
Darrin L. Smith;V. Wysocki;R. Colorado;O. E. Shmakova;M. Graupe;T. Lee
采用低能离子-表面碰撞方法研究了烷基、CF 3、CF 3CF 2和C1 0 F2 1封端的烷基硫醇盐在金基底上的自组装单分子膜（SAMs），以确定硫醇盐尾部基团的不同取代度对SAMs的影响.氟封端的自组装膜进行了比较和对比，以前检查的CF 3封端的Langmuir-Blodgett膜。多原子（M + .对于苯和吡嗪）和原子（Mo + . Cr +。）离子以各种碰撞能量（20-70 eV）与不同的SAM膜碰撞。结果表明，CF 3取代CH 3对离子-表面相互作用，包括能量转移（碎裂）、电子转移（中和）和原子/基团转移（反应）有重要影响.然而，轻微的渗透到膜的深度是明显的，并说明了某些离子表面反应产物的形成和这些产物的强度。这种穿透对低能离子-表面碰撞有明显的影响。此外，一系列的CF 3（CH 2）nS-Au膜（其中n = 12，13，14，15）的结果表明，离子表面反应的变化与氟原子的取向存在于端基。低能离子与这些相对明确的表面碰撞的结果允许进一步表征碰撞事件，这些碰撞事件有可能成为表面分析中有价值的工具。
Self-assembled monolayers (SAMs) formed from alkyl-terminated, CF 3 -terminated, CF3CF2-terminated, and C 1 0 F 2 1 -terminated alkanethiolates on gold substrates were examined by low-energy (eV) ion-surface collisions to determine the impact of varying the degree of fluorination of the thiolate tail group. The fluorine-terminated SAMs are compared and contrasted to previously examined CF 3 -terminated Langmuir-Blodgett films. Polyatomic (M + . for benzene and pyrazine) and atomic (Mo + . and Cr + . ) ions were collided with the different SAM films at various collision energies (20-70 eV). Data indicate that substitution of CH 3 with CF 3 as the terminal group has a substantial influence on the ion-surface interactions, including energy transfer (fragmentation), electron transfer (neutralization), and atom/group transfer (reaction). However, slight penetration into a depth of the film is apparent and illustrated with the formation of certain ion-surface reaction products and theintensities ofthose products. This penetration has a noticeable effect on low-energy ion-surface collisions. Also, results for a series of CF 3 (CH 2 ) n S-Au films (where n = 12, 13, 14, 15) illustrate that ion-surface reactions vary with the orientation of the fluorine atoms that are present in the terminal group. The results from collisions of low-energy ions with these relatively well-defined surfaces allow further characterization of the collision events that have the potential to become valuable tools in surface analysis.