Facile Phase‐Separation Approach to Encapsulate Functionalized Polymers in Core–Shell Nanoparticles

Core–shell nanoparticles filled with a reactive hydrophobic azide‐terminated polyisobutylene are prepared by a combination of miniemulsion and solvent evaporation techniques. Successful encapsulation is achieved by the rational selection of the polymer pair that displays a large difference in solubility parameters (δ) and interfacial tensions with water (γpolymer/water). By labeling the two polymers with different fluorescent dyes, core–shell structures can be visualized by fluorescence microscopy. After extraction of the polymer present in the core, hollow morphologies are observed by transmission electronic microscopy. The encapsulation efficiency of the reactive polymer increases with decreasing surfactant concentration, with values as high as 90%. This study presents a simple and reaction‐free method to encapsulate reactive polymers. Considering the drawbacks of self‐healing agents with low molar mass, such as volatility and higher propensity for leakage from nanocapsules, the encapsulation of reactive polymers in nanocontainers is an interesting and new alternative for self‐healing materials.