Man Viet Hoang, Li Mai Suan, Wang Junmei, Derreumaux Philippe, Nguyen Phuong H
Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland.
J Chem Phys. 2019 Jul 14;151(2):024103. doi: 10.1063/1.5109101.
We develop a molecular nanoscaled model for tubular motors propelled by bubble propulsion. The motor is modeled by a carbon nanotube, and the bubble is represented by a particle interacting with water by a time-dependent potential. Effects of liquid viscosity, fuel concentration, geometry, and size of the tube on the performance of the motor are effectively encoded into two parameters: time scales of the bubble expansion and bubble formation. Our results are qualitatively consistent with experimental data of much larger motors. Simulations suggest that (i) the displacement of the tube is optimized if two time scales are as short as possible, (ii) the compromise between the performance and fuel consumption is achieved if the bubble formation time is shorter than the velocity correlation time of the tube, (iii) the motor efficiency is higher with slow expansion, short formation of the bubble than fast growth but long formation time, and (iv) the tube is propelled by strong forces on the order of mN, reaching high speeds up to ∼60 m/s. Our simulation may be useful for refining and encouraging future experimental work on nanomotors having the size of a few nanometers. The tiny size and high speed motors could have great potential applications in real life.
我们开发了一种由气泡推进驱动的管状马达的分子纳米尺度模型。该马达以碳纳米管为模型，气泡由一个通过随时间变化的势与水相互作用的粒子表示。液体粘度、燃料浓度、管的几何形状和尺寸对马达性能的影响被有效地编码为两个参数：气泡膨胀的时间尺度和气泡形成的时间尺度。我们的结果在定性上与大得多的马达的实验数据一致。模拟结果表明：（i）如果两个时间尺度尽可能短，则管的位移将得到优化；（ii）如果气泡形成时间短于管的速度相关时间，则可在性能和燃料消耗之间达成妥协；（iii）气泡缓慢膨胀、形成时间短的马达效率高于快速生长但形成时间长的马达；（iv）管受到约mN量级的强力推动，速度可达约60 m/s。我们的模拟对于完善和推动未来关于几纳米尺寸纳米马达的实验工作可能有用。这种微小尺寸和高速的马达在现实生活中可能具有巨大的潜在应用。
