This study introduces an attractive nanoemulsion (ANE) system that is characterized by the reversible dipolar interaction between drops induced by hydrophilic polymer chain conformation on their surface. For this, we first synthesized amphiphilic ABA triblock copolymers, poly (ethylene oxide)-b-poly (ε-caprolactone)-b-poly (ethylene oxide) (PEO-b-PCL-b-PEO) via urethane condensation reaction, while controlling their molecular weights and block ratios. When the triblock copolymer is associated with lecithin, the interdroplet attractions over a wide volume fraction range of the dispersed oil phase occurred. Thanks to formation of a percolated network of stable drops, our ANEs exhibited the outstanding emulsion stability without any changes in the drop size, even in a highly-concentrated state (close to 0.7 fraction) and in the repeated freeze-thaw test. From the dense suspension rheology studies, interestingly, we figured out that the enhanced modulus of ANEs at room temperature was attributed to the effective association of PEO chains with lecithin occurring across droplets. Furthermore, we observed that the longer the molecular weight of PEO, the more easily interdrop association occurred. This implies that the chain conformation of the PEO plays an important role in regulation of the droplet-droplet association of ANEs. All these findings support the potential use of our ANE system over a wide range of applications in drug delivery, cosmetic and food formulations, and life sciences.

Dense suspension rheology studies of attractive nanoemulsions for characterization of polymer chain conformation-driven dipolar interdrop association

256th National Meeting (2018)

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