位于金属表面的基酸盐自组合单层中相应的固体-固体相变
Y Wang1, J G Solano-Canchaya, M Alcamí
1Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain. yang.wang@uam.es
Journal of the American Chemical Society
|July 26, 2012
概括
在Pt{111}上基酸盐的自组合单层 (SAM) 呈现出温度诱导的固体-固体相位过渡. 冷却导致基酸盐链倾斜,由链链相互作用驱动,影响设备设计.
科学领域:
- 表面科学是一门学科.
- 材料科学 材料科学 材料科学
- 计算化学的计算化学
背景情况:
- 自组装单层 (SAM) 在表面科学和纳米技术中至关重要.
- 了解SAM中的相位过渡是物质财产控制的关键.
- 金属表面上的基酸盐形成有序结构,具有潜在的应用.
研究的目的:
- 为了研究Pt上基酸盐SAM中的温度诱导的相变.
- 阐明控制链方向变化的机制.
- 确定相关系统中类似相位过渡的条件.
主要方法:
- 使用了分子动力学模拟.
- 最初的潜在能量表面被用于准确的力场.
- 模拟集中在Pt上具有不同链长的基酸盐的SAM上.
主要成果:
- 对于具有>12个碳原子的SAM,预测了温度诱导的相应的固体-固体相变.
- 冷却引起了从直立到倾斜的链条配置的突然变化.
- 这一转变是由链间范德瓦尔斯相互作用决定的,而不是头组相互作用.
结论:
- 在Pt(111) 上的基酸盐SAM表现出明显的温度依赖的相位行为.
- 这些发现表明了温度控制电子或光学设备的潜力.
- 特定的格子间距 (4.7-4.9 Å) 有助于这些相位过渡,不包括Au/Ag上的密集包装.
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