A Water-in-Powder cosmetic is one encapsulating a large amount of water with powders. In this study we explain why the cosmetic is possible. First we focused on hydrophilic and hydrophobic balance of nano-sized powder surface. We looked into the surface state of powders with the gas adsorption test and discovered the functional powders that have the optimized balance of hydrorepellency due to fractal surface and hydrophilicity due to free hydroxyl groups. By using this material, we created a new powder technology that can encapsulate a large quantity of water stably. We also looked into how the powders encapsulated water by observation with wet-SEM and how the encapsulated water is stabilized by measuring water mobility with
17O-NMR. As a result, we developed a new technology with water and powder. By encapsulating a large amount of water, we achieved a cosmetic with many unique characteristics: the powder cosmetic can change into liquid by application of friction on skin, it gives us comfort in use and provides a watery, cool feel. It also provides excellent makeup function by spreading smoothly on skin to form a uniform makeup coating.
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