Jamison Jennifer A, Krueger Karl M, Yavuz Cafer T, Mayo J T, LeCrone Denise, Redden Jacina J, Colvin Vicki L
Department of Chemistry, MS-60, 6100 Main Street, Rice University, Houston, Texas 77005, USA.
ACS Nano. 2008 Feb;2(2):311-9. doi: 10.1021/nn700144m.
Centrifugation is an increasingly important technique for nanomaterial processing. Here, we examine this process for gold, cadmium selenide, and iron oxide nanocrystals using an analytical ultracentrifuge. Such data provide an accurate measure of the sedimentation coefficients for these materials, and we find that this parameter has a significant dependence on the size and surface coating. Conventional models for particle sedimentation cannot capture the behavior of these nanocrystals unless the density of the nanocrystals is described by a size-dependent term that accounts for both the inorganic core and the organic coating. Using this modification in the particle sedimentation framework, it is possible to estimate sedimentation coefficients from information about the nanocrystal core and surface coating dimensions. Such data are useful in choosing the speeds for a centrifugation process and are particularly important when bimodal nanocrystal distributions are present.
离心分离是纳米材料加工中一项日益重要的技术。在此，我们使用分析型超速离心机研究了金、硒化镉和氧化铁纳米晶体的这一过程。这些数据为这些材料的沉降系数提供了精确测量，并且我们发现该参数对尺寸和表面涂层有显著依赖性。除非纳米晶体的密度由一个考虑无机核心和有机涂层的尺寸相关项来描述，否则传统的颗粒沉降模型无法捕捉这些纳米晶体的行为。在颗粒沉降框架中使用这种修正，就有可能根据纳米晶体核心和表面涂层尺寸的信息来估算沉降系数。这些数据在选择离心过程的速度时很有用，并且在存在双峰纳米晶体分布时尤为重要。
