Nothing is more comfy to slip on over sleepwear than a soft cotton robe. Because cotton is breathable, moisture-wicking and hypoallergenic, it's an ideal material for robes of all styles. Some brands offer 100% cotton robes, while others will use a blend of cotton and polyester.
Cotton is extremely versatile, too. Interlock knits in fine pima cotton are lightweight and silky. Pique cotton and wovens may be heavier weight, patterned or woven in patterns, like jacquard. Some cotton robes are brushed for extra softness against the skin. As far as women's sleepwear, cotton robes will maintain their shape and stay soft, wash after wash.