Core–Shell Polymeric Microcapsules with Superior Thermal and Solvent Stability

A protective polydopamine (PDA) coating is applied to core-shell microcapsule surfaces by the polymerization of dopamine monomers. A neutral aqueous solution and the addition of an oxidant (i.e., ammonium persulfate) are crucial for microcapsule survival and the initiation of PDA polymerization, respectively. The resulting PDA coating is a dense and uniform layer approximately 50 nm thick. The PDA protective coating significantly increases capsule stability at an elevated temperature (180 °C) and in a variety of organic solvents and acidic/basic solutions that otherwise lead to deflation and loss of the core content of uncoated microcapsules.