To analyze the thermal insulation effect in textiles, waterproof, and breathable nylon fabrics PCMs microcapsules (PCMMcs) were prepared by wet and dry coating processes. The morphology, water vapor permeability (WVP), water penetration resistance (WPR), and peel strength of the PCMMcs-coated fabrics were characterized. At the same time, DSC was used to measure the thermal insulation properties of the PCMMcs-treated fabrics as a means of testing the thermal storage/release capacity according to their phase change temperature. The result showed that the heat storage capacity of the PCMMcs-treated fabrics prepared by wet coating was noticeably better than that of the PCMMcs-untreated samples, whereas the PCMMcs treatment had an insignificant effect on the heat capacity of the fabrics prepared by the dry coating process. From the SEM analysis, it was found that the PCMMcs were physically unstable during the dry coating process, so, they could not be observed. Also, the WVP, WPR, and peel strength were found to decrease with increasing PCMMcs contents. POLYM. ENG. SCI., 49:1151-1157, 2009. (C) 2009 Society of Plastics Engineers