Mixed Adlayer of Alkanethiol and Peptide on GaAs(100): Quantitative Characterization by X-ray Photoelectron Spectroscopy

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• 作者：Heeyeon P. Wampler ; Dmitry Y. Zemlyanov ; Kangho Lee ; David B. Janes ; Albena Ivanisevic
• 刊名：Langmuir
• 出版年：2008
• 出版时间：April 1, 2008
• 年：2008
• 卷：24
• 期：7
• 页码：3164 - 3170
• 全文大小：355K
• 年卷期：v.24,no.7(April 1, 2008)
• ISSN：1520-5827

文摘

Homogeneous and mixed adlayers composed of an alkanethiol (1-octadecanethiol, ODT) and a peptide(CGISYGRKKRRQRRR) on GaAs(100) were formed in two different solvent systems: phosphate-buffered saline(PBS) and N,N-dimethylformamide (DMF). The chemical composition of each adlayer was characterized by X-rayphotoelectron spectroscopy (XPS). The data showed that the makeup of the adlayer and its stability largely dependson the solvent used. Angle-resolved XPS also revealed that the adlayer thickness and tilt angles were different fromvalues obtained from ellipsometry measurements and vastly varied between the two solvents used. The coverage dataextracted from the XPS measurements indicated that homogeneous adlayers of peptide in PBS buffer form a multilayeredfilm. Homogeneous alkanethiol adlayers exhibited monolayer coverage under all solvent treatments. Coadsorbedlayers containing both alkanethiol and peptide have fractional monolayer coverage in both solvents.