Using Nanoparticles to Confine Molecular Self-Assembly

使用纳米粒子限制分子自组装

• 批准号: 0755654
• 负责人: Guangzhao Mao
• 金额: $ 29.85万
• 依托单位: Wayne State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-15 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0755654&HistoricalAwards=false
• 关键词: Using; Nanoparticles; Confine; Molecular; Self

CBET-0755654MaoThe project is at the interface of two active research areas: nanoparticle arrays and organic thin films. Self assembled monolayers of amphiphiles are relevant to biological processes and in lubrication, colloidal stabilization, and detergency. Nanoparticle arrays are applicable to thin film devices. The overall objective of this proposal is to explore the possibility of nucleating molecular nanorods on inorganic nanoparticle surfaces in order to explore the nanoconfinement effect in templated crystallization and to generate a unique hybrid nano architecture. Experimental and theoretical evidence in non epitaxial seed mediated nucleation suggests that a critical seed size and the presence of other confinement effects are necessary for the selective formation of rod like nanoclusters attached to the nanoparticle seeds. To test this hypothesis, gold nanoparticles of various sizes will be used and physicochemical experiments will be conducted to characterize and understand the underlying molecular self assembly mechanisms of the hybrid architectures. The proposed study will continue a preliminary investigation of co-deposited cadmium selenide nanoparticles with eicosanoic acid, by using gold nanoparticles of varying sizes immobilized on solid substrates as models. Additionally, our ability to regulate the overall geometry of the hybrid by controlling seed shape, and our ability to impart electrical conductivity to the organic component, will be explored. The kinetics of crystallization will be probed by in situ AFM experiments. In addition to ongoing collaboration with Dr. Helmuth Mohwald at the Max Planck Institute of Colloids and Interfaces, the proposal will seek to characterize the hybrid ultrathin film structure by neutron diffraction/scattering through collaboration with Dr. Stuart M. Clarke at the University of Cambridge. Intellectual Merit. Shape restrictive nucleation stems from the high curvature of a nanoparticle surface, which imposes unsustainable strains for tangential crystal growth. Other alternative controls for nanoparticle mediated nucleation of nanorods will be explored, which may include high supersaturation, favorable wetting of seed by nucleus, 1D growth habit, and seed surface defects. The seed mediated nucleation represents an alternative approach to nanoparticle and nanorod integration. Unlike previous work using seeds of the same building blocks as the nuclei, the proposed work will investigate the formation of the nanoparticle/nanorod architecture using heterogeneous and non epitaxial seed mediated nucleation, i.e. the nucleus is made of different building blocks (organic) than those of the seed (inorganic). The confinement control for small molecules at molecular length scales, 0.11 nm, is more difficult than the confinement by polymer length scales, 10100 nm. To date, very few reliable measurements of microscopic mechanisms and kinetics of molecular crystal formation at early stages have been made. If successful, the solutionbased, room temperature approach will facilitate divergent combinatorial and scalable chemistry for the construction of branched nano objects. The hybrid nanostructure allows the size dependent properties of each component to be tuned independently. Broader Impacts. Crystallization confined to nano media impacts a number of emerging technologies including thin film and high throughput screening devices. From a human resources perspective, U.S. students will gain international research experience by working with world leading institutions in interfacial materials research. Underrepresented undergraduate students will be recruited from the Michigan Louis Stokes Alliance for Minority Participation Program to participate in this global research training.

CBET-0755654 Mao该项目是两个活跃的研究领域的接口：纳米颗粒阵列和有机薄膜。两亲分子的自组装单分子膜与生物过程以及润滑、胶体稳定和去污有关。纳米颗粒阵列适用于薄膜器件。该提案的总体目标是探索在无机纳米颗粒表面上成核分子纳米棒的可能性，以探索模板结晶中的纳米限制效应并产生独特的混合纳米结构。在非外延晶种介导的成核的实验和理论证据表明，一个关键的种子大小和其他限制效应的存在是必要的选择性形成的棒状纳米团簇连接到纳米粒子种子。为了验证这一假设，将使用各种尺寸的金纳米颗粒，并进行物理化学实验，以表征和理解混合体系结构的潜在分子自组装机制。拟议的研究将继续初步调查共沉积的硒化镉纳米粒子与花生酸，通过使用固定在固体基质上的不同尺寸的金纳米粒子作为模型。此外，我们的能力，通过控制种子的形状，并赋予导电性的有机成分的混合物的整体几何形状进行调节，将进行探讨。结晶动力学将通过原位AFM实验来探测。除了正在进行的与马克斯普朗克胶体和界面研究所的Helenstein Mohwald博士的合作外，该提案还将寻求通过与Stuart M.克拉克在剑桥大学。智力优势。形状限制性成核源于纳米颗粒表面的高曲率，这对切向晶体生长施加了不可持续的应变。将探索用于纳米颗粒介导的纳米棒成核的其他替代控制，其可包括高过饱和度、通过核的种子的有利润湿、1D生长习性和种子表面缺陷。种子介导的成核代表了纳米颗粒和纳米棒集成的替代方法。与以前使用与核相同的构建块的种子的工作不同，所提出的工作将研究使用异质和非外延种子介导的成核的纳米颗粒/纳米棒结构的形成，即核由与种子（无机）不同的构建块（有机）制成。在分子长度尺度0.11 nm处对小分子的限制控制比通过聚合物长度尺度10 - 100 nm的限制更困难。迄今为止，很少有可靠的测量微观机制和动力学的分子晶体形成的早期阶段。如果成功的话，基于溶液的室温方法将促进用于构建分支纳米物体的发散组合和可扩展化学。混合纳米结构允许独立地调节每个组分的尺寸依赖性性质。更广泛的影响。局限于纳米介质的结晶影响了许多新兴技术，包括薄膜和高通量筛选装置。从人力资源的角度来看，美国学生将通过与世界领先的界面材料研究机构合作获得国际研究经验。代表性不足的本科生将从密歇根州路易斯·斯托克斯少数民族参与计划联盟招募参加这项全球研究培训。