A new type of organoclay composite (PMMT) with good heat storage and release capacity was produced by intercalating n-hexadecane with Na-montmorillonite (Na-MMT) in a surfactant-assisted medium. The expansion of Na-MMT galleries by a Na salt of 4-dodecylbenzene sulfonic acid (SDS) solution prior to the intercalation of n-hexadecane enhanced the process. In the XRD analysis, expansions of the d spacings in the (0 01) plane were observed in all PMMT samples, indicating that the intercalation of n-hexadecane in the galleries of Na-MMT was successfully achieved. The most successful PMMT sample, prepared by intercalating 9 mmol n-hexadecane per gram of Na-MMT, displayed a high heat capacity (126 J g(-1)) and good thermal durability. The sample also had a higher thermal conductivity compared to pure n-hexadecane samples.The manufacture of the PCM-clay composites by the method of surfactant-mediated intercalation of n-hexadecane into Na-MMT is recommended to enhance the thermal performance of different thermal storage materials. (C) 2011 Elsevier B.V. All rights reserved.