Owing to its high reactivity and the ability to tune its endcap groups, PPA has been lately utilized in drug delivery applications. In one recent study, UV-sensitive PPA microcapsules containing different types of drugs were prepared. Once the capsules were subjected to a UV-light trigger, an unzipping reaction took place and the shell ruptured which led to the release of the core contain of these microcapsules. A unique advantage of these microcapsules is that they allow the immediate release of the drug upon exposure to the trigger rather than its continuous release over a period of time ranging from minutes to hours as other common microcapsules function. In an earlier publication, DiLauro et al. reported the ability to predesign and control the thickness of the microcapsule shells and length of the PPA used to form the shell, which have stimuli-responsive endcaps allowing head-to-tail fluoride-triggered depolymerization.