Unique Crystallization Characteristics of Pickering High Internal Phase Emulsion Templated Porous Constructs

Abstract

To study the crystallization behavior of polymeric chains under the influence of porosity, the thermal properties of various nonporous and porous poly(ε-caprolactone) (PCL) based constructs were investigated. Porous cross-linked PCL nanocomposite constructs were fabricated utilizing in situ polymerization of CL-based surfactant-free Pickering high internal phase emulsions (HIPEs), stabilized using modified fumed silica nanoparticles (mSiNP) at a minimal concentration of 0.6 wt %. The corresponding nanocomposite constructs exhibited polyhedral pore morphology with significant pore roughness due to the presence of mSiNP. DSC thermograms of nonporous constructs illustrated diminished crystallization temperature and kinetics upon cross-linking and inclusion of mSiNP which confirmed suppressed mobility of polymer chains. Further introduction of porosity led to substantial supercooling, resulting in crystallization temperatures as low as −24 °C. Changes in the crystal structure of various nonporous and porous constructs were also studied using XRD. The crystallization behavior of porous constructs was finally evaluated using Jeziorny, Ozawa, and Mo theories under nonisothermal conditions. Significant deviation from the theoretical model, as observed in the case of porous constructs, implied a complex crystallization mechanism that eventually was not only controlled by the chain immobility due to cross-linking but also heterogeneity present in the wall thickness of the constructs. The unique meltingcrystallization phenomenon observed in such constructs may further be expanded to other systems of high heat capacity for utilization as energy storage materials.

Synergistic Effect of Asphaltene, Resin, and Wax Improving the Emulsification and Interfacial Properties of a High-Phase-Inversion Thin Oil

“…We acknowledge that the high-phase-inversion phenomenon may be an external manifestation of the interaction of natural surfactants at the interface. Considering the intimate connection between the field of emulsions and interface science, − we extensively discuss the properties of the oil–water interface, including interfacial tension and viscoelasticity. By delving into the intricate interactions between oil and water, our objective is to gain a better understanding of the mechanism behind the high phase inversion in thin oil and provide novel insights into the behavior of thin-oil emulsions.…”