Raveendran Abhilash, Meli M-Vicki
Department of Chemistry and Biochemistry, Mount Allison University, 63C York Street, Sackville, New Brunswick E4L 1G8, Canada.
ACS Omega. 2017 Aug 10;2(8):4411-4416. doi: 10.1021/acsomega.7b00682. eCollection 2017 Aug 31.
In this study, the effects of ligand phase, morphology, and temperature on the elastic modulus of free-standing alkanethiol-capped gold nanoparticle membranes are reported. Langmuir films of 2.5 nm gold nanoparticles capped with tetradecanethiol were prepared at temperatures above and below the phase transition temperature ( ) of the ligand shell and transferred to holey carbon grids (containing 1.2 μm holes) to form free-standing membranes. Force-indentation measurements are used to measure the elastic modulus of the membranes using an atomic force microscope in the temperature range 10-40 °C. These films are compared with membranes of dodecanethiol-capped gold nanoparticles, which do not undergo a ligand order-disorder transition in the temperature range investigated. The ligand phase effect is observed in the tetradecanethiol-capped gold nanoparticle films, where an abrupt change in the elastic modulus is seen near . The temperature (relative to ) during the fabrication of the films is determined to play an important role in tuning the mechanical strength of these films in this temperature range by both changing the nature of the interparticle interactions and by affecting microscale film morphology.
在本研究中，报告了配体相、形态和温度对自支撑烷硫醇封端金纳米颗粒膜弹性模量的影响。在配体壳层的相变温度（ ）之上和之下的温度下制备了由十四烷硫醇封端的2.5 nm金纳米颗粒的朗缪尔膜，并将其转移到有孔碳网格（含有1.2μm的孔）上以形成自支撑膜。使用原子力显微镜在10 - 40°C的温度范围内通过力压痕测量来测量膜的弹性模量。将这些膜与十二烷硫醇封端的金纳米颗粒膜进行比较，后者在所研究的温度范围内不会发生配体有序 - 无序转变。在十四烷硫醇封端的金纳米颗粒膜中观察到配体相效应，在 附近弹性模量出现突然变化。确定在膜制备过程中的温度（相对于 ）通过改变颗粒间相互作用的性质以及影响微观尺度的膜形态，在该温度范围内调节这些膜的机械强度方面起着重要作用。
