The synthesis of triblock copolymers is demonstrated by using on both ends differentially functionalized polymeric initiators. Attaching for example on one side of a PEG chain an hydroxy end-group and on the other side a Grubbs catalyst, a triblock copolymer consisting of polynorbornene, polyethylene oxide and polylactide can be obtained. As ROMP and ROP are not interfering with each other both monomers, lactide and norbornene, can be polymerized simultaneously and a triblock copolymer generated in a one-pot reaction. This concept can be further extended to other polymerization techniques like ATRP.<br/>In a second part triblock copolymers with an ABA structure will be shown. In this case polypeptides which are on both sides end-functionalized with serine units are used as initiators for ROP of lactides yielding polylactide-polypeptide-polylactide copolymers. Using a special polypeptide sequence allows for a selective degradation of the block copolymers by enzymes which are overexpressed in cancer cells. Due to this reactivity the copolymers can be used in cancer therapy which is shown in cell experiments.<br/>In a final part block copolymers are shown which are switchable by UV irradiation from hydrophobic to hydrophilic. They are based on polymers which are in one block in the side chain modified with pyrene units. By irradiation of the copolymers the polycyclic hydrocarbon groups can be cleaved and polar groups selectively in one block generated. This allows for an easy polarity change without additional reagents which gives interesting prospectives for many materials as it will be shown for e.g. in drug carriers or composites.

Block copolymers by simultaneous copolymerisation of different monomers, unusual initiators and polymeranalogous transformations

253rd National Meeting (2017)

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