The association between a non-ionic microemulsion and hydrophobically modified PEG. A rheological investigation

The thickening effect of a hydrophobically modified polymer in an O/W microemulsion is investigated. The hydrophobically modified polymer is a triblock copolymer, alkyl end-capped poly(ethylene glycol) and the microemulsion is based on a non-ionic surfactant, pentaethylene oxide dodecyl ether (C12E5) and decane. The rheological properties vary strongly with microemulsion droplet volume fraction, with temperature and with end-caps of the polymer. Particularly interesting are a maximum in viscosity as a function of droplet volume fraction, a decrease in cross-link life-time and very strong temperature dependences. These can be understood on the basis of interdroplet distances and interaction