Graphite nanofibers (GNFs) embedded in paraffin phase change material are found to settle to the bottom of the sample when subjected to repeated thermal cycling. The majority of this settling is found to occur over the first heating/cooling cycle. A method is developed to prevent GNF settling by creating a shape stabilized phase change material using high density polyethylene (HDPE) as a stabilizing polymer. The shape stabilized samples reduced or eliminated GNF settling over repeated thermal cycles with as little as 10% HDPE by weight. (C) 2011 Elsevier Ltd. All rights reserved.