"Controlled synthesis pathways towards precision design of tailor-made PPVs."
Poly(p-phenylene vinylenes) (PPVs) and their derivatives are one of the most studied conjugated materials over the last decades. Although originally used in electronic applications, more recent developments opened a variety of application pathways for PPVs in the area of biosensors and biomedical research. The excellent fluorescent properties and low charge carrier mobility of PPVs make them ideal candidates to replace existing bioimaging agents such as organic fluorescent markers. In this thesis the mechanistic understanding of the PPV synthesis pathway, ultimately leading to the use of PPV materials in theranostic applications is presented.
In order to achieve this goal, micro flow reactors are used to probe the kinetics of the polymerization as an easy way to screen a variety of reaction parameters. In this way, the excellent sulfinyl precursor route and its thermal elimination step is combined with the advantages of flow reactors, yielding a continuous process for the synthesis of highly-defined conjugated PPV materials in a simple and easily scalable manner. In addition, theoretical pathways are tackled to gain more insight into the mechanistic details of the polymerization. The obtained kinetic data is implemented in the software Predici®, which is used as a tool to map the radical sulfinyl PPV polymerization.
Figure 1: left: Coupled flow reactor set-up of the polymerization (left) and elimination (right) of (MDMO)-PPV as observed under UV irradiation (λ =365 nm); right: Non-toxic Profluorescent (MDMO)-PPV micelles are loaded with Doxorubicin and used as drug delivery vesicle
Additionally, controlled polymerization of PPV-copolymers provides materials with defined molecular weight and specific chemical functionality, leading to PPV materials with tunable optical properties. By combining both experimental as well as theoretical insights, not only a deeper fundamental understanding of PPV polymerizations is obtained, but also new pathways towards more sophisticated structures and thus new applications in the biomedical field are opened. First result on the use of PPV micelles as bioimaging probe as well as drug delivery systems are promising. Hence, a first step for the use of PPVs in theranostics was taken.