Microcapsules or macrocapsules have a core composition that includes a phase change material (PCM) encapsulated within a polymer wall with an outer shell having a siloxane tethered to an exterior surface of the polymer wall by a surfactant. The siloxane may form a crystalline or a sol-gel outer shell. Methods of making such capsules and textile fabrics and clothing incorporating such capsules include treating pre-formed capsules with a surfactant solution followed by treating with a compound containing a siloxane functional group. The surfactant connects or tethers the siloxane to the exterior surface of the polymer wall and the siloxane forms an outer shell of the capsules.