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In this study, we developed novel multifunctional raw materials, polyoxyethylene/polyoxypropylene dimethyl ether (EPDME). EPDME is a random copolymer of ethylene oxide and propylene oxide. The structure of the obtained EPDME was confirmed by Infrared (IR) absorption and NMR spectra. EPDME, which dissolves in water and oil. The compound has the following effects: [1] a high moisture-retaining effect without sticky feeling, [2] a preventing effect on dry skin, and [3] an improving effect on dry skin by daily application. It was also found that the application of EPDME in combination with glycerol resulted in a synergistic effect on the dry skin. When EPDME was formulated to lipsticks (oily bases), a high moisture-retaining effect was found. EPDME is a useful cosmetic ingredient that can give a good skin care effect in both water-based formula and oil-based formula. As the polarity of EPDME can easily be controlled, it is expected to be applicable for various cosmetics in the near future.

In this study, the effect of polyoxyethylene (POE)/polyoxypropylene (POP) dimethylethers [EPDMEs] with various molecular weights and polarities on self-organizing structures of pentaethyleneglycol dodecylether (C12E5) was investigated. The investigation on micelle formation of C12E5 in EPDME aqueous solutions showed that [1] EPDME disturbed the micelle formation of C12E5, [2] the micelle formation was also disturbed more strongly with the increase of temperature, and [3] the surface tension of solution became low in spite of the decrease of the amount of adsorption of C12E5 with the increase of the concentration of EPDME. The result of measuring the cloud points of C12E5 in EPDME solutions unveiled that the cloud points became remarkably higher at high EPDME concentration, suggesting that the rise of the cloud points in EPDME solutions might be caused by the decrease of the aggregation number of C12E5. Moreover, it was speculated that C12E5 and EPDME might aggregate partially and form mixed micelles, since the cloud points of their mixture appeared beyond 50 °C. Liquid paraffin could be solubilized at a specific temperature above the could point of C12E5 in 27wt% EPDME (17/4) aqueous solution. It was speculated that [1] a special micelle containing oil might be formed when the cohesive force of the hydrophobic groups of C12E5 increased by solubilizing liquid paraffin, [2] EPDME distributed to the hydrophilic chain of C12E5, and [3] the curvature of the interfacial film became positive. Therefore, as described in the previous study, EPDME functions as a hydrophilic co-surfactant when the concentrations of both EPDME and polyoxyethylene nonionic surfactants are high, because EPDME may probably distribute on the polyoxyethylene chain of the surfactant. A microemulsion can be formed in a wide temperature range by preventing the aggregation of nonionic surfactants with the increase of temperature.

New multifunctional raw materials for cosmetics, polyoxyethylene (POE) /polyoxypropylene (POP) dimethylether [EPDME] were previously developed by the authors. The present study presents a novel emulsifying method by which ultrafine emulsions of particle size less than 100 nm can be easily prepared using EPDME. The equilibrium phase state of the water - oil - surfactant - EPDME was examinated using a phase diagram so as to clarify the underlying mechanism in the preparation of ultrafine emulsions and the results indicated the following: [1] a special microemulsion phase is formed in a region different from that of the normal microemulsion phase when oil, EPDME, surfactant and water are mixed in the proper proportions and [2] ultrafine emulsions form in a two-phase region (O + Wm) when the composite of the microemulsion phase is diluted with water. The chemical structure of EPDME is similar to that of the polyoxyethylene chain in polyoxyethylene nonionic surfactants. EPDME may thus be considered a hydrophilic co-surfactant and a special microemulsion phase is formed at high EPDME and polyoxyethylene nonionic surfactant. EPDME may possibly be distributed in the polyoxyethylene chain of the polyoxyethylene surfactant. When diluting this microemulsion phase, EPDME rapidly decreases in concentration and, in free form virtually unadsorbed onto the oil - water interface may diffuse in the bulk water phase from polyoxyethylene chains in surfactants. It would then follow that an ultrafine emulsion consisting only of nonionic surfactant and oil may form in excess.