Tuning of interfacial interactions in poly(isoprene) ferroelastomer by surface modification of embedded metallic iron nanoparticles

Zero-valent metallic iron nanoparticles (NPs) with modified surface were embedded in poly(isoprene) (PI) and the enthalpy of interfacial adhesion in resulted ferroelastomers was evaluated. Iron NPs were synthesized by the method of electrical explosion of wire (EEW) in inert gas. Modification of their surface was performed by the in situ liquid treatment of the active condensed NPs in the EEW installation. The enthalpy of mixing of poly(isoprene) with Fe NPs was determined using thermochemical cycle based on the isothermal calorimetry measurement of the enthalpy of dissolution of PI/Fe composites in chloroform at 25$^\circ$C. Using these values the enthalpy of adhesion of PI to the surface of modified Fe NPs was evaluated using Langmuir-type isotherm. It was shown that the enthalpy of adhesion strongly depends on the properties of the surface of Fe NPs and its modification. It was the lowest in the case of oxidized Fe NPs and the highest for Fe NPs which surface was modified by pre-deposited polymeric shells.