Polymer capsules with core-shell structure have attracted considerable interest in a variety of scienti•c •elds, ranging from synthetic chemistry, biotechnology, and pharmaceuticals to diagnostics [1-7]. Several methods, including self-assembly, polymerization, phase separation, and templating synthesis, have been developed to prepare polymer capsules. The size, composition, surface functionality, and stability of the capsules can be •nely tuned to a large degree [8-10]. The capsule shell, isolating the core and environment, can protect encapsulated cargos from deteriorating effects such as oxidation and moisture. Different building blocks with designed properties, such as optics, magnetism, conductivity, and targeting, make the polymer capsules multifunctional for applications in the disciplines of chemistry, physics, biology, engineering, pharmaceuticals, and materials science.