The growth of C-60 nanowhiskers (C(60)NWs) prepared by a modified liquid-liquid interfacial precipitation method is investigated, focusing on the effect of solvent ratio and water content in the C-60-toluene-isopropyl alcohol (IPA) solution system. The precipitation of C(60)NWs was markedly influenced by the solvent ratio of toluene to IPA, and the C(60)NWs were found to grow longer above a critical diameter (D-c), which depends on the solvent ratio. The addition of a small amount of H2O to the C-60-toluene-IPA solution promoted the growth of C(60)NWs. This catalytic effect of water on the growth of C(60)NWs was confirmed also by the experiment using heavy water (D2O) and by the decrease of growth activation energy of C(60)NWs with increase of H2O content in the C-60-toluene-IPA solution. (C) 2010 Elsevier B.V. All rights reserved.