Department of Chemistry and Biochemistry, Mount Allison University, 63C York Street, Sackville, New Brunswick, Canada.
Langmuir. 2012 Jan 10;28(1):377-81. doi: 10.1021/la202895n. Epub 2011 Dec 16.
In this study, we report the effects of the alkyl chain length on alkanethiol-capped gold nanoparticle Langmuir films. Gold nanoparticles (2-3 nm) capped with C(n)H(2n+1)SH (n = 5-12, 14-16, 18) were prepared via a two-phase synthesis. The films were sampled by Langmuir-Schaefer horizontal transfer at various points in the pressure-area isotherm and monitored with transmission electron microscopy. Changes in surface pressure, temperature, and alkyl chain length did not lead to observable differences in the mesoscale film morphology. Pressure-area isotherms at 22 °C, however, revealed that the work of compression and the collapse pressure are directly dependent on alkyl chain lengths of 14 carbons or greater. Variable temperature isotherms suggest that the work of compression is strongly affected by the phase state (i.e., crystalline vs liquid-like) of the gold-thiolate self-assembled monolayer (SAM) capping the nanoparticles.
在这项研究中，我们报告了烷基链长对巯基烷烃封端的金纳米粒子Langmuir 膜的影响。通过两相合成制备了用 C(n)H(2n+1)SH（n = 5-12、14-16、18）封端的 2-3nm 金纳米粒子。通过 Langmuir-Schaefer 水平转移在压力-面积等温线上的不同点采样，并通过透射电子显微镜进行监测。表面压力、温度和烷基链长的变化并未导致在介观膜形态上观察到明显差异。然而，22°C 的压力-面积等温线表明，压缩功和崩溃压力直接取决于长度为 14 个碳原子或更长的烷基链。变温等温线表明，压缩功受金-硫醇自组装单层（SAM）覆盖纳米粒子的相态（即结晶态与液态）的强烈影响。
