电势诱导的N-异丁酰基-L-半胱氨酸分子在金(111)表面的相转变 |
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基金项目: | the National Natural Science Foundation of China(91227201);the National Natural Science Foundation of China(21527805) |
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摘 要: |
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关 键 词: | 自组装 硫醇 相转变 电势诱导 电化学扫描隧道显微镜 密度泛函理论 |
收稿时间: | 2016-12-19 |
Potential-Induced Phase Transition of N-Isobutyryl-L-cysteine Monolayers on Au (111) Surfaces |
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Authors: | Ai-Xi CHEN Hong WANG Sai DUAN Hai-Ming ZHANG Xin XU Li-Feng CHI |
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Abstract: | Functional solid substrates modified by self-assembled monolayers (SAMs) have potential applications in biosensors, chromatography, and biocompatible materials. The potential-induced phase transition of N-isobutyryl-L-cysteine (L-NIBC) SAMs on Au (111) surfaces was investigated by in-situ electrochemical scanning tunneling microscopy (EC-STM) in 0.1 mol·L-1 H2SO4 solution. The NIBC SAMs with two distinct structures (α phase and β phase) can be prepared by immersing the Au (111) substrate in pure NIBC aqueous solution and NIBC solution controlled by phosphate buffer at pH 7, respectively. The as-prepared α phase and β phase of NIBC SAMs show various structural changes under the control of electrochemical potentials of the Au (111) in H2SO4 solution. The α phase NIBC SAMs exhibit structural changes from ordered to disordered structures with potential changes from 0.7 V (vs saturated calomel electrode, SCE) to 0.2 V. However, the β phase NIBC SAMs undergo structural changes from disordered structures (E < 0.3 V) to γ phase (0.4 V < E < 0.5 V) and finally to the β phase (0.5 V < E < 0.7 V). EC-STM images also indicate that the phase transition from the β phase NIBC SAMs to the α phase occurs at positive potential. Combined with density functional theory (DFT) calculations, the phase transition from the β phase to the α phase is explained by the potential-induced break of bonding interactions between ——COO- and the negatively charged gold surfaces. |
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Keywords: | Self-assembly Thiol Phase transition Potential-induced Electrochemical scanning tunneling microscopy Density functional theory |
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