The computational study of silicon doping and atomic defect influences on the CNT's nano-pumping process: Molecular dynamics approach

Today, nanotubes are used in biological systems due to their low toxicity and unique functionalization capability. Carbon nanotubes (CNTs) are considered one of the best carriers in drug delivery systems. In this study, the effect of silicon (Si) doping and atomic defects on the CNT's nano-pumping process has been investigated by molecular dynamics (MD) simulation, and the changes in kinetic energy, potential energy, entropy, stress, and nano-pumping time are investigated. The results show that increasing Si doping increases CNT's C20 molecule exit time. Numerically, as the Si doping increases from 0.05% to 4%, the exit time of the C20 molecule increases from 8.07 to 9.16 ps. Also, an increase in Si doping leads to a decrease in kinetic energy and lattice stress and an increase in the potential energy and entropy of the system. So, the nanostructure with 1% doping performs better (optimal performance) than other samples. The effect of atomic defect with 0.5%, 1% and 1.5% on CNT's surface is investigated. The results show that the kinetic energy of samples decreases by increasing atomic defect from 0.5% to 1.5%. Also, the results show that the kinetic energy of the sample with a 0.5% atomic defect is higher than its defect-free state. The numerical results show that potential energy and entropy increase with the increasing the atomic defect. This increase can lead to an increase in the time it takes for the nanoparticle to exit the nanotube and disrupt the nano-pumping process.