Osmotic Propulsion: The Osmotic Motor

智力优势：设计能够将储存的化学能转化为运动的纳米引擎是纳米技术的一个关键变革挑战，特别是对于能够自主运行的纳米引擎。最近的实验表明，利用表面催化反应，即所谓的催化纳米马达，为纳米级和微级物体的运动提供动力是可能的。虽然已经提出了许多观点，但造成这种运动的确切机制尚不清楚。本项目提出了一种非常简单的机制：渗透推进。表面化学反应产生局部的反应物和产物的浓度梯度，从而对马达产生净渗透力。电机能够利用随时存在的随机热运动，通过化学反应，以实现定向自主运动。这项研究表明，这种“渗透”马达是可能的，并解决了这样的问题：马达能移动多快？它能产生多大的力？它能载多少“货物”？它能泵出多少液体？它的运动如何被控制和引导？可以使用什么化学物质？这种渗透电机的效率是多少？更广泛的影响：渗透推进提供了一种非常简单和通用的手段，将化学能转化为机械运动和功。通过渗透推进利用胶体系统中的随机热运动可以彻底改变微流体和纳米器件的设计和操作，应用于材料的定向自组装，微和纳米处理器的热管理，以及化学和生物传感器的设计和操作。该研究将为可作为渗透马达的胶体粒子的构建和运行提供明确的处方。如果我们希望实现未来的纳米级技术：微小的医疗“纳米机器人”可以在细胞水平上接触人体内部的疾病，并进行修复，就必须进行这项基础性和变革性的研究。或者在“芯片上的实验室”设备中，可以通过微通道感应道路，搅拌或分离纳米升的化学物质。或者甚至是一个纳米马达，它能感知到特定分子的入侵，游向它，并在这个过程中关闭一个通道，触发生物污染物的警报开关。只要正确理解和利用这种规模的运动物理，任何这些类型的设备都是可能的。最后，自主电机的研究可能有助于更广泛地理解生物系统中发生的化学机械转导，也可以创造出模仿生物体的新型人工电机，并可以用来执行有用的任务。

CBET-0754967BradyIntellectual Merit: The design of nanoengines that can convert stored chemical energyinto motion is a key transformative challenge of nanotechnology, especially for nano-engines that can operate autonomously. Recent experiments have demonstrated that it is possible to power the motion of nanoscale and microscale objects by using surface catalytic reactions so-called catalytic nanomotors. The precise mechanism responsible for this motion is not known, although a number of ideas have been put forth. This project involves a very simple mechanism is proposed: osmotic propulsion. A surface chemical reaction creates local concentration gradients of the reactive and product species which generate a net osmotic force on the motor. The motor is able to harness the ever present random thermal motion via a chemical reaction to achieve directed autonomous motion. This research demonstrates that such an 'osmotic' motor is possible and addresses such questions as: How fast can the motor move? How large of a force can it generate? How much 'cargo' can it carry? How much fluid can it pump? How can its motion be controlled and directed? What chemistry can be used? What is the efficiency of such an osmotic motor?Broader Impact: Osmotic propulsion provides a very simple and general means to convert chemical energy into mechanical motion and work. Exploiting the random thermal motion in colloidal systems via osmotic propulsion can revolutionize the design and operation of microfluidic and nanodevices, with applications in directed self-assembly of materials, thermal management of micro- and nanoprocessors, and the design and operation of chemical and biological sensors. This research will provide explicit prescriptions for the construction and operation of colloidal particles that can be used as osmotic motors. This fundamental and transformative study must be undertaken if we wish to enable many of the nano-scale technologies envisioned for the future: tiny medical 'nanobots' that can access human illness inside the body, at the cellular level, and repair it. Or devices that can sense their way through micro channels in 'lab on a chip' devices, stirring or separating nano-liters of chemicals. Or even a nano-motor that senses intrusion of a specific molecule, swims toward it, and closes a channel in the process triggering an alarm switch for biological contaminants. Any of these types of devices is possible provided the physics of motion at that scale is correctly understood and utilized. And finally, studies of autonomous motors may help to understand more generally chemomechanical transduction as occurs in biological systems, and also create novel artificial motors that mimic living organisms and which can be harnessed to perform useful tasks.