Efficiency of Various Devices and Theories to Collect Nanoparticles Directly onto

描述(由申请人提供)：对于评估纳米颗粒的形态、元素分析以及颗粒计数和大小，透射电子显微镜是一种非常有用的技术。这项技术最近已经成为表征暴露在空气中的纳米颗粒的必要工具。这项研究的具体目的是比较使用透射电子显微镜扩散采样器(TDS)、静电沉淀采样器(EPS)和热电沉积采样器(TPS)直接将空气中的工程纳米颗粒(ENPs)沉积到网格上进行材料表征的可用方法。研究目标包括：粒度分布、沉积均匀度和易用性的比较。将产生测试纳米颗粒气溶胶，并使用每种方法的三个设备并排收集样品，以及记录颗粒浓度的NanoScan SMPS(TSI3910型，10-420 nm)和光学颗粒计数器(TSI3330型，300 nm-10�m)。实验将在普渡大学的伯克纳米技术洁净室实验室进行。这项研究将检验下列假设：(1)基本气溶胶理论可用于预测颗粒物在瞬变电子显微镜网格上的收集；(2)TPS比TDS和EPS更高效地将小于200 nm的颗粒物直接收集到瞬变电子显微镜网格上，EPS在收集200 nm-10�m范围的颗粒物方面比TPS和TDS更高效，并且所有技术都不能有效地收集大于1�m的颗粒物；以及(3)所有三种机制收集的纳米粒子都是随机分布在网格表面。这项研究的结果将为开发适当使用采样器收集纳米颗粒提供信息技术结果。此外，研究结果将为进一步改进现有采样器或开发新设计的采样器提供参考，为今后的研究提供更好的性能。

DESCRIPTION (provided by applicant): Transmission electron microscope (TEM) is a very useful technique for evaluating nanoparticle morphology, for elemental analysis, and for particle counting and sizing. This technique has recently become a required tool to characterize exposure to airborne nanoparticles. The specific aim of this proposed research is to compare the available methods using TEM diffusive sampler (TDS), electrostatic precipitation sampler (EPS) and thermophoretic sampler (TPS) for directly depositing airborne engineered nanoparticles (ENPs) onto grids for material characterization. Research objectives include: comparison of size distributions, deposition uniformity and the ease of use. Test nanoparticle aerosols will be generated and samples will be collected side-by-side with three devices using each method, along with the NanoScan SMPS (TSI Model 3910, 10-420 nm) and Optical Particle Counter (OPC) (TSI Model 3330, 300 nm- 10 �m) to record the particle concentration. Experiments will be performed in the Birck Nanotechnology cleanroom laboratory at Purdue University. This research will test the following hypotheses: (1) Basic aerosol theory can be used to predict particle collection onto TEM grids; (2)TPS is more efficient than TDS and EPS for collecting particles less than 200 nm directly onto a TEM grid, EPS is more efficient than TPS and TDS for collecting particles from 200 nm - 10 �m, and none of the techniques are efficient at collecting particles larger than 1 �m; and (3) Nanoparticles collected by all three mechanisms are randomly distributed across a grid surface. The results from this research will provide informative technical results to develop the adequate use of samplers for collecting nanoparticles. In addition, the results will provide the input for further modifications to existin samplers or the development of a newly-designed sampler which can provide better performance for future research.