Kinetic and thermodynamic correlation for prediction of morphology of nanocapsules with hydrophobic core via miniemulsion polymerization

Abstract

Here, a series of nanocapsules containing n-hexadecane (HD) as a liquid core were prepared by engulfing it in the copolymer of methyl methacrylate (MMA) with 2-ethylhexyl acrylate (EHA) and methacrylic acid (MAA) through in situ miniemulsion polymerization. The aim of this work is to investigate the effects of the initiator type and EHA and MAA as highly hydrophobic and hydrophilic comonomers, respectively on the properties of resulting nanocapsules. A combination of some thermodynamic parameters and thermal behavior was developed to study the characteristics of the resulting capsules. These thermodynamic parameters were obtained from spreading coefficients extracted from interfacial tension analyses. By increasing the polarity of the comonomers in the shell of the capsules by using MAA, some deviations from ideal core–shell toward half-moon morphology were observed according to partial engulfing of HD. These results were approved by SEM, TEM and also the study of thermal characteristics of capsules using DSC thermograms.