NER: Nanoparticle Stability by Quantum Design of Van der Waals Forces

abstractcts - 0403646 d。宾夕法尼亚州立大学Velegol纳米技术有望在材料、光学、电子和生物医学应用方面取得巨大进步。目前用于制造纳米级产品的自上而下的技术（例如，原子力显微镜，电子束光刻）速度慢且昂贵，这使得它们难以用于批量生产量子点，纳米结构催化剂，纳米颗粒润滑剂，高级纳米颗粒药物载体和其他纳米产品。一种更可行的消费级生产方法是“自下而上的组装”，即智能粒子自组装成结构。纳米粒子应用的一个关键瓶颈是功能粒子的分散和自组装。挑战在于范德华力（VDW）导致非特异性和不希望的粒子聚集。目前稳定颗粒的技术——尤其是分散剂的使用——限制了颗粒功能化的能力。为了实现纳米粒子的分散，必须找到新的方法来降低VDW的吸引力。这些力总是存在于原子和分子之间，它们已经在各种情况下被研究了75年。但是与计算纳米粒子的VDW力有关的问题开辟了一个新的研究领域，因为纳米粒子的VDW力不同于微米大小的粒子或原子。知识价值：这个NSF NER的愿景是利用量子原理探索设计固有稳定的纳米粒子系统。我们的初步计算表明了调整VDW力的新机会，甚至可能使它们具有排斥性。由于涉及到巨大的参数空间，仅从实验中不大可能出现精确的调谐VDW力的技术。量子计算对这个项目的成功至关重要。在这篇文章中，我们将……1. 1 .开发用于精确模拟纳米粒子的VDW力所需的工具箱，并将其编程为“自底向上”软件，使纳米技术专家可以轻松使用；2 .计算技术相关体系的VDW力，包括核壳纳米粒子和各种共溶剂体系中的纳米粒子；用浊度稳定性实验评估计算的准确性。这种新颖的模型将使我们能够探索巨大的参数空间-颗粒材料，尺寸，形态，核壳结构，共溶剂介质等-这不仅是目前无法测量的，而且需要设计技术来导航。超越目前原子或微米级系统的范例，我们将考虑晶体结构和离散原子的影响，纳米粒子的极化改变，以及核壳和共溶剂系统。我们的方法将使用原子VDW力文献中众所周知的技术，并将其转化为纳米粒子系统。在这个NER中，我们寻求对早期计算的支持，这些计算将证明纳米颗粒系统分散的“设计”方法的可行性。该提案涉及纳米尺度主题的建模和仿真，以及纳米尺度主题的制造过程，因为我们的目标是实现纳米颗粒系统的批量生产和加工。更广泛的影响：这项研究将有两个更广泛的影响。第一个是“自底向上”，这个软件工具将体现我们的计算。这个新颖的免费软件基础设施的愿景是，纳米技术专家可以输入系统参数（例如，材料，颗粒大小和体积分数），并根据纳米颗粒VDW力和稳定性的最强大计算，接收关于分散纳米颗粒的具体建议。从长远来看，BottomUp将是一个用户友好的工具，将扩展到其他类型的力，包括静电、耗竭和疏水力。第二个更广泛的影响来自利用现有优势的“行动潜力”，这是宾夕法尼亚州立大学的一个项目，让10到14岁的孩子接触刺激的科学体验。与该组织的合作旨在激励学生学习和使用现代物理学来解决应用问题。

AbstractCTS-0403646D. Velegol, Pennsylvania State UniversityNanotechnology promises huge advances in materials, optical, electronics, and biomedicalapplications. Current top-down techniques (e.g., atomic force microscopy, e-beam lithography) for creating nanoscale products are slow and expensive, making them difficult to use for bulk production of quantum dots, nanostructured catalysts, nanoparticle lubricants, advanced nanoparticle drug vectors, and other nano products. A more viable approach to consumer-scale production is "bottom up assembly", in which smart particles self-assemble into structures. A critical bottleneck to nanoparticle use is the dispersion and self-assembly of functional particles. The challenge is that van der Waals (VDW) forces cause non-specific and undesired aggregation of the particles.Current techniques for stabilizing particles - especially the use of dispersants - limit the ability tofunctionalize the particles. To achieve nanoparticle dispersion, new methods must be identified for reducing VDW attractive forces. These forces always exist between atoms and molecules, and they have been studied in various contexts for 75 years. But the issues involved with calculating VDW forces for nanoparticles open a new field of study, since nanoparticle VDW forces are different from those for micron size particles or atoms.Intellectual merit: The vision of this NSF NER is to explore the design of nanoparticle systems that are inherently stable, using quantum principles. Our preliminary calculations suggest new opportunities for tuning VDW forces, perhaps even making them repulsive. Precise techniques for tuning VDW forces are highly unlikely to emerge from experiments alone, due to the huge parameter space involved. Quantum calculations are essential to the success of this project. In this NER we will ... 1. develop the tool chest needed to model accurately the VDW forces for nanoparticles, andprogram this into "BottomUp" software to make it easily available to nanotechnologists;2. calculate VDW forces for technologically-relevant systems, including core-shell nanoparticlesand nanoparticles in various co-solvent systems;3. assess the accuracy of the calculations using turbidity stability experiments.This novel modeling will enable us to explore the huge parameter space - particle material, size,morphology, core-shell structure, co-solvent media, etc. - that is not only unmeasurable currently, but also which requires design techniques to navigate. Going beyond current paradigms for atomic or micron-size systems, we will consider effects of crystal structures and discrete atoms, altered polarizabilities of nanoparticles, and core-shell and co-solvent systems. Our approach will use techniques well-known in the atomic VDW force literature, and transform them for use on nanoparticle systems. In this NER we seek support for early-stage calculations that will demonstrate the feasibility of the "design" approach for nanoparticle system dispersion. The proposal addresses the modeling and simulation at the nanoscale theme, as well as the manufacturing processes at the nanoscale theme, since our goal is to enable the bulk production and processing of nanoparticle systems. Broader impact: This research will have two broader impacts. The first is "BottomUp", the software tool that will embody our calculations. The vision for this novel piece of freeware infrastructure is that a nanotechnologist can enter systems parameters (e.g., materials, particle sizes and volume fraction) and receive specific suggestions for dispersing the nanoparticles based on the most powerful calculations available for nanoparticle VDW forces and stability. In the longer term, BottomUp will be a user-friendly tool that will be extended to other types of forces, including electrostatic, depletion, and hydrophobic forces. The second broader impact comes from leveraging existing strengths with "Action Potential", a Penn State program that exposes 10 to 14 year olds to a stimulating science experience. Collaborations with this organization will aim to inspire students to learn and use modern physics for applied problems.