Abstract
The functional properties of foundation and sunscreen products need to be long lasting because they are applied to the skin during for a long time in a day. Thus, the surface of the powder in cosmetics is coated with hydrophobic agents to make it water resistant. However, the water-resistant property of the powder makes it difficult to wash it off with water easily. To solve this problem, we focused on two types of poly (trimethylene carbonate) (PTMC) derivatives which show spontaneous surface rearrangements depending on wet or dry conditions. We found out that PTMC with poly (dimethylsiloxane) (PDMS-PTMC) and poly (ethylene glycol) monomethyl ether (mPEG-PTMC) showed change in the contact angle because of the surface rearrangement of polymers under the wet condition. The response time under the wet condition and change in contact angle were able to be controlled by the polymer chain length and blend ratio of PDMS-PTMC and mPEG-PTMC. PDMS-PTMC and mPEG-PTMC polymer-coated powder showed hydrophobicity for a certain period, and then became hydrophilic after a certain period in water. Furthermore, by using a powder coated with PDMS-PTMC and mPEG-PTMC with the optimal polymer chain length and blend ratio for the powdery foundation, it is possible to develop a product that is both long lasting and easily washed off.
