Modification of challenging materials using atom transfer radical polymerization (ATRP)

Dr. Piotr Mocny
Lecture of the lecture cycle
13.2.2025 10:00, Lecture room A

Radical chemistry is an effective tool to modify materials and to adapt their properties. Even materials that are considered inert, such as polyolefins react with radicals, e.g. via H-abstraction and the formed macroradicals initiate radical polymerization. ATRP is also employed to graft polymers from nanoparticles, which requires attachment of a halide initiator. Within this talk, two examples of challenging substrates will be covered; poly(vinylidene fluoride) (PVDF) and eutectic gallium indium (EGaIn) nanodroplets. Modification of PVDF facilitates its use in filtration membranes or cathode binders, while grafted EGaIn may be easier processed into composite materials for soft robotics and stretchable electronics. A number of publications report relatively easy modification of PVDF by ATRP. However, its initiation mechanism remains controversial due postulated cleavage of very strong C-F bonds. I will present its modification by photomediated ATRP system with eosin Y as a photocatalyst. The method enabled oxygen tolerant, fast (1 h), and mild (room temperature) grafting of poly(meth)acrylates from PVDF derivatives. It was also explored for surface-initiated growth of polymer brushes (growth of > 20nm∙min-1) from thin PVDF films. Dehydrofluorination was observed to be an important prerequisite for the grafting. Grafting of EGaIn by ATRP is challenging due to its interference with copper catalysts. This issue was addressed by using diblock copolymer macroinitiator surfactants, which provided excellent stabilization of EGaIn nanodroplets. ATRP performed from the stabilized nanodroplets enabled controlled growth of polymers, as manifested by linear increase of conversion, as well as the size of the nanodroplet-polymer hybrids with time. The progress of the grafting was conveniently monitored by NMR and DLS, which is useful for generation of precise hybrid architectures for structure-property relationship studies.

The lecture is presented in English