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Modeling and Motion Analysis of a Nano Mobile Robot Using Molecular Dynamics

Nemati Estahbanati, Alireza | 2018

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 51038 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Meghdari, Ali; Sohrabpour, Saeed; Nejat Pishkenari, Hossein
  7. Abstract:
  8. With the rapid progress of technology, the fabrication of smaller electronic and mechanical systems becomes more necessary. To make a small-scale system with better performance, one way is to create it from molecular components. In recent decade, many attempts have been devoted to the fabrication of molecular machines for manipulation of particles at nanoscales. In this project, the motion of two of most basic nanocars namely the Nanocar and the Nanotruck were simulated on gold and silver substrate at different conditions, both of four wheels and the nanotruck chassis is flexible. In the first chapter of this report, some of the most important natural and artificial machines are mentioned and different types of nanocars are introduced as well. Since, many of nanocars have C60 wheels; the motion of C60 on gold substrate at different temperatures is investigated in chapter 2. The motion of the nanocar and the nanotruck on flat gold substrate is studied in the next section. Thereafter, the result of the simulations are compared and validated with the available experimental data. The effect of silver impurity, stepwise substrate, and substrate with holes on the motion of the nanocar and the nanotruck is studied at different conditions and temperatures. The results demonstrate that C60 has three different regimes of motion, dependent on temperature: rare jumps to adjacent cells, frequent jumps, and continuous motion. It can move freely on the substrate at temperatures higher than 200 k. The motion range of the nanocar and the nanotruck is less than C60 and they can mover on flat gold substrate only at temperature higher than 500k. In addition, heavier and more flexible nanocar chassis reduces its maneuverability compared to a nanotruck. Simulations results are compared with available data from experimental studies conducted in recent years, and an acceptable agreement between the simulation results and experiments was observed. The result of next section shows that stepped substrate limits the motion of C60, the nanocar, and the nanotruck in one direction and makes their motion more predictable and controllable. Besides, it demonstrates that motion of C60 and nanocars are faster on the top side of step relative to the down side. Using stepped substrates, a pathway with the desired route can be fabricated for directing the motion of C60 and nanocars. In general, a hole in the substrate acts as an obstacle against motion of C60 and nanocars at low temperatures. However, at temperature of 400k and higher, the hole acts as a trap and restricts their motion range. At temperature higher than 400k, C60 and nanocars can exit from the single atom holes but they cannot free themselves 4 atoms (2×2) holes. The study of silver impurity on the gold substrate reveals that silver zone works as a repellent obstacle against motion of C60 and nanocars. The nanocar and the nanotruck cannot enter the silver section even at temperature of 600 k. but C60 can penetrate to the silver zone at temperature of 300 K and can easily enter the silver zone at 600 K considering the effect of silver impurity on the motion of the nanocar and the nanotruck, we can control their motion by fabricating gold path on the silver substrate. Investigating the effect of temperature gradient on gold substrate demonstrates that it is propellant for the nanocar and the nanotruck, which push them to migrate from the hot zone to the colder section. These phenomena can be employed to create directional motion in the C60, the nanocar, and the nanotruck. However, the nanotruck is affected by the gradient temperature and its motion is more directional in relative to the nanocar. In addition, increasing the mean temperature of the substrates makes nanocars motion less directional and more diffusive
  9. Keywords:
  10. Potential Energy ; Molecular Dynamics ; Nanorobot ; Nanocar ; Nanotruck ; Diffusion Motion ; Molecular Machines

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