New methods for controlling molecular motion on surfaces

控制表面分子运动的新方法

基本信息

批准号：
1412402
负责人：
Charles Sykes
金额：
$ 44.68万
依托单位：
Tufts University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2014
资助国家：
美国
起止时间：
2014-08-01 至 2017-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1412402&HistoricalAwards=false
关键词：
New methods controlling molecular motion

项目摘要

In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program, Charles Sykes of Tufts University is investigating ways to direct and control the motion of molecules on surfaces. This motion occurs in two ways: molecules can travel across the surface in straight or curved lines or they can spin in place like a top. Currently, it is not well-understood how energy flowing through molecules causes them to move. This is preventing the advancement of new technologies. New methods for separating or purifying molecules require that these two types of movement be controlled, yet this can be very difficult to do. Unique new applications, including tiny molecular-sized pumps, sensors, optoelectronics, and assemblies, could become possible if a way can be found to control these motions. In this research, a sophisticated imaging system known as a scanning tunneling microscope is being used to visualize the motion of individual molecules on surfaces. Electrical pulses can be applied to the molecules in order to gain a better understanding of how energy flow leads to molecular motion. The ultimate goal of the work is the discovery of valuable design principles for the construction of molecular machines and molecular-sized devices. The work is having a broader impact through presentations the researchers are making at local high schools. Newly developed science demonstrations, "meet a scientist" days, and the inclusion of high school students in the research are bringing the work to a broad audience. The wider public is also engaged in this research through the production of YouTube videos featuring this cutting-edge research.The research is aimed at developing new methods for the controlled rotation of molecules and their unidirectional translation across surfaces by addressing several key questions. First, the relationship between a molecule's intrinsic chirality, its adsorption configuration, and its potential energy landscape on the surface must be understood. Next, molecular functionality that enables cargo to be bound and released is investigated. Finally, the electrically excited hopping of molecules with ratchet-like energy landscapes is being studied to better control unidirectional motion, providing more general approaches to the directional transport of molecules on surfaces that do not require the molecules to be a specific shape/functionality. While the electronic or vibrational states of the molecules in these experiments is to be excited with electrons from a scanning tunneling microscope tip, this method for globally inducing directed motion of all the molecules on a surface is possible by coupling to the same modes either with a macroscopic electron or light source. Discovery of novel microscopic mechanisms for directed molecular motion on surfaces will provide important proof of principle demonstrations that are generalizable in other systems and fields. This type of enabling technology is crucial for the rational design of new approaches for mass transport, separations and enantiopurifications.

在这个由大分子，超分子和纳米化学计划资助的项目中，塔夫茨大学的查尔斯·赛克斯（Charles Sykes）正在研究指导和控制分子在表面上的运动的方法。这种运动以两种方式发生：分子可以直线或弯曲线穿过表面，或者它们可以像顶部一样旋转。目前，尚不能够理解通过分子流动的能量如何使它们移动。这阻止了新技术的发展。分离或净化分子的新方法需要控制这两种运动，但这可能很难做到。如果可以找到可以控制这些运动的方法，则独特的新应用，包括微小的分子大小泵，传感器，光电子和组件，就可以实现。在这项研究中，使用称为扫描隧道显微镜的复杂成像系统可视化单个分子在表面上的运动。电脉冲可以应用于分子，以便更好地了解能量如何导致分子运动。这项工作的最终目标是发现有价值的设计原理，以构建分子机和分子大小的设备。这项工作是通过研究人员在当地高中进行的演讲产生的更大影响。新开发的科学示范，“遇见科学家”时代，在研究中包括高中生正在将这项工作带给广泛的受众。通过制作以这项尖端研究为特色的YouTube视频，更广泛的公众也参与了这项研究。该研究旨在通过解决几个关键问题来开发分子及其在跨表面的单向翻译的新方法。首先，必须了解分子内在的手性，其吸附构型与其在表面上的势能景观之间的关系。接下来，研究了能够绑定并释放货物的分子功能。最后，正在研究用类似棘轮的能量景观的分子的电动跳跃，以更好地控制单向运动，为分子在表面上的方向转运提供了更一般的方法，而分子在表面上不需要分子是特定的形状/功能。虽然这些实验中分子的电子或振动状态是要与扫描隧道显微镜尖端的电子激发，但这种方法可以通过将所有分子在表面上进行全球诱导的运动方法与宏观电子或光源一起耦合。在表面上发现新型的微观机制，将提供重要的原理证明证明，这些证明是可以在其他系统和领域中推广的。这种类型的促成技术对于合理设计大众运输，分离和对映体的方法至关重要。