Molecular dynamics simulations were carried out to investigate carbon nanotube (CNT) interactions and dispersion in a polyethylene oxide (PEO)/water solution. The potential of mean forces (PMF) which embodies the entropic and enthalpic contributions by the solvent and the polymer molecules were computed. The relative enthalpic and entropic contributions to the PMF were studied in order to understand the CNT interaction mechanisms in solution. An adaptive biasing force (ABF) method was used to speed up the PMF calculations. The simulation results provide detailed atomic arrangements and atomic interactions between the CNTs and surrounding molecules (PEO and water). This molecular level computational study provides insights into the CNTs interactions with PEO polymer/water systems. (C) 2010 Elsevier Ltd. All rights reserved.