Light Responsive Polymer Micro and Nano Capsules
A significant amount of academic and industrial research efforts are devoted to the encapsulation of active substances within micro or nanocarriers. The ultimate goal of core shell systems is the protection of the encapsulated substance from the environment, and its controlled and targeted release. This can be accomplished by employing "stimuli responsive" materials as constituents of the capsule shell. Among a wide range of factors that induce the release of the core material, we focus herein on the light stimulus. In polymers, this feature can be achieved introducing a photo sensitive segment, whose activation leads to either rupture or modification of the diffusive properties of the capsule shell, allowing the delivery of the encapsulated material. Micro and nano encapsulation techniques are constantly spreading towards wider application fields, and many different active molecules have been encapsulated, such as additives for food packaging, pesticides, dyes, pharmaceutics, fragrances and flavors or cosmetics. Herein, a review on the latest and most challenging polymer based micro and nano sized hollow carriers exhibiting a light responsive release behavior is presented. A special focus is put on systems activated by wavelengths less harmful for living organisms (mainly in the ultraviolet, visible and infrared range) as well as on different preparation techniques, namely liposomes, self assembly, layer by layer, and interfacial polymerization.
Polymers