Compressed ethylene-assisted formation of the reverse micelle of PEO-PPO-PEO copolymer

The triblock copolymer (EO)(27)(PO)(6I),(EO)(27) aggregates in p-xylene upon addition of ethylene, An abrupt increase of water solubilization is observed at a certain ethylene pressure. The molar ratio of water to EO segment (W(0)) can be as high as 4.2 under suitable conditions. The reverse micelles can solubilize ionic substances, such as methyl orange. The polarity of the water domains increases with increasing W(0) as shown by a solvatochromic study. The structure of the reverse micelles is characterized by small-angle X-ray scattering and Fourier transform infrared. The results indicate the existence of lamellar structure and "bulk" (hydrogen-bonded) water (H(2)O and D(2)O) in the reverse micellar system. The formation and breaking of the reverse micelles can be repeated by adjusting the ethylene pressure.