Department of Chemistry, and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA.
Proc Natl Acad Sci U S A. 2012 Feb 14;109(7):2240-5. doi: 10.1073/pnas.1119301109. Epub 2012 Jan 17.
We report that triangular gold nanoprisms in the presence of attractive depletion forces and repulsive electrostatic forces assemble into equilibrium one-dimensional lamellar crystals in solution with interparticle spacings greater than four times the thickness of the nanoprisms. Experimental and theoretical studies reveal that the anomalously large d spacings of the lamellar superlattices are due to a balance between depletion and electrostatic interactions, both of which arise from the surfactant cetyltrimethylammonium bromide. The effects of surfactant concentration, temperature, ionic strength of the solution, and prism edge length on the lattice parameters have been investigated and provide a variety of tools for in situ modulation of these colloidal superstructures. Additionally, we demonstrate a purification procedure based on our observations that can be used to efficiently separate triangular nanoprisms from spherical nanoparticles formed concomitantly during their synthesis.
我们报告称，在有吸引力的耗散力和排斥静电的情况下，三角形金纳米棱柱在溶液中组装成平衡的一维层状晶体，颗粒间的间距大于纳米棱柱厚度的四倍。实验和理论研究表明，层状超晶格的异常大的 d 间距是由于耗散和静电相互作用之间的平衡，这两者都源于表面活性剂十六烷基三甲基溴化铵。已经研究了表面活性剂浓度、温度、溶液的离子强度以及棱柱边缘长度对晶格参数的影响，这为这些胶体超结构的原位调节提供了多种工具。此外，我们还展示了一种基于我们的观察结果的纯化程序，该程序可用于有效地从合成过程中同时形成的球形纳米颗粒中分离出三角形纳米棱柱。
