PEO Saturated Macromonomers

An often studied group of nonionic surfactants (emulsifiers) is poly(ethylene oxide) monoalkyl ether of the general structure CmH2m+1-(OCH2CH2)n-OH (Cm-(EO)n). 

In aqueous solutions of Cm-(EO)n amphiphilic molecules, two interesting features are observed. First, isotropic micellar solutions undergo phase separation on heating. Such behavior is typical of hydrophobic interaction and is also observed for several water-soluble polymers. Hydrophobic interaction results from a change of order in the water structure [54]. Second, at high concentration, liquid crystalline phase behavior is observed with several structures [55]. 

Phase diagrams of many Cm-(EO)n systems were found to demonstrate the complex influence of hydrophilic-hydrophobic balance on miscibility gap and mesophases [37]. An unambiguous description of the solution structure is difficult because size and shape of micellar aggregates can change with temperature and concentration. 

Mixed micelles, comprising both polymerized and free surfactants, are formed once the critical association concentration (CAC) of the free am-phiphiles is reached. The CAC is typically much smaller than the CMC for the formation of free micelles. As the fraction of unpolymerized surfactants within the mixed micelles grows, their structure approaches that of free micelles. 

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