Download or read book Molecular Dynamics Simulations of Carbon Nanotubes in Liquid Flow written by Wenzhong Tang and published by ProQuest. This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular dynamics (MD) simulation method is used to simulate the dynamics of nanotubes in liquid flow. This study was motivated by our experimental work on the fabrication and mechanical properties characterization of multi-walled carbon nanotube(MWNT)-high density polyethylene (HDPE) composites fabricated by a melt processing method. SEM and TEM pictures show that the nanotubes are dispersed in the polymer matrix in small aggregates, the size of which decrease with the shearing strength in the suspension. Three types of behaviors are addressed. First, a high aspect ratio nanotube is modeled as a flexible fiber and its dynamics in simple shear flow are simulated by coupling flexible fiber dynamics based on continuum mechanics, with drag forces on the nanotube obtained from MD simulations. Results show that curved nanotubes in simple shear flow become straight and aligned along the shearing direction. Calculations also show that the viscosity of a dilute nanotube suspension increases with nanotube aspect ratio (Ar) and volume fraction (V f). For Ar = 400 and V f =0.708%, the suspension viscosity is two orders higher than the suspending liquid, which is comparable to reported viscosity measurements. The results also show that suspension viscosity decreases as the initial curvature of the nanotube increases. Second, Dynamics of a short nanotube (Ar