Dynamical behavior of water inside a capped single-walled carbon nanotube

Dynamical behavior of water confined inside a capped single-walled carbon nanotube (SWCNT) is investigated at different temperatures via the Molecular Dynamics (MD) Simulation method. Water in a SWCNT behaves in the fashion of random walk and increases amplitudes with temperature. Moreover, the SWCNT's tip vibrates more significantly as temperature increases. The water molecules embedded nanotubes exhibit less thermal noise amplitude, indicating increases in effective stiffness in the water-nanotube composite. Further, the vibrational amplitude of a water-embedded SWCNT's tip is more noticeable during the initial transient state at the beginning of our MD simulations, and gradually decays, and reaches a steady state, as MD simulation time increases. The variation of vibrating amplitude of the SWCNT's tip increases linearly as temperature increases when no water is present inside. The tip vibration exhibits the largest amplitude when temperature is at the boiling point of water. Moreover, the tip vibration increases monotonically as temperature increases, providing information to estimate the effective Young's modulus of the water-nanotube composite. The diffusion pathways of water inside a SWCNT are also studied in terms of temperature changes.