실린더 형태의 나노와이어와 표면 사이의 응착력 평가를 위한 분자동역학 시뮬레이션 연구

Adhesion force of nanomaterials such as nanoparticle, nanowire, and nanorods should be significantly considered for its mechanical applications. However, examination of the adhesion force is limited since it is technically challenging to carry out experiments with such small objects. Therefore, in this work, molecular dynamics simulation (MDS) was conducted to determine the adhesion force between a nanowire and a flat surface, which could not be readily assessed through experiments. The adhesion force of a cylindrical-shaped nanowire was assessed by performing MDS and applying an equation of Van der Waals interaction. Simulation was conducted in two steps: indentation of a spherical tip on the flat surface and indentation of a cylinder on the flat surface, because the purpose of the simulation was comparing the results of the simulation and calculation of the Van der Waals interaction equation. From the simulation, Hamaker constant used for the equation of Van der Waals interaction was determined to be 2.93 °o 10?18 J. Using this constant, the adhesion force of the nanowire on the flat surface was readily estimated by calculating Van der Waals equation to be approximately 65~89 nN with respect to the diameter of the nanowire. Moreover, the adhesion force of the nanowire was determined to be 52~77 nN from the simulation It was observed that there was a slight discrepancy (approximately 15~25%)between the results of the simulation and the theoretical calculation. Thus, it was confirmed that the calculation of Van der Waals interaction could be utilized to assess the adhesion force of the nanowire.