Tailor-made polymers by reversible deactivation radical polymerization (RDRP) (in water)

People

Jutta Rieger, François Stoffelbach

Thanks to our expertise in reversible deactivation radical polymerization (RDRP), using various control methods such as RAFT, NMR or ATRP polymerization, our group synthesises custom copolymers presenting different microstructures and architectures (linear, star-like, block-like, grafted…) depending on the targeted applications. These polymers can be functionalized along the polymer backbone or on the chain ends.

We described for instance the synthesis of a trifunctional RAFT agent and its use to prepare well-defined star-like polymers that were later used to prepare an hydrogel.

In another project, we have shown that the synthesis of amphiphilic copolymer with a simple architecture (diblock AB, triblock ABC, tetrablock ABBA) or complex (star or BAB) wa spossible in water, notably through the use of the PISA process in « one-pot ».The use of mono-, di- or trifunctional RAFT agents, (classical or with inverted structure) allowed us to produce in water these copolymers with an excellent control and at high solid content.The obtained amphiphilic copolymers self-assemble in these conditions under self-stabilised particles. In the particular case of BAB copolymers (A = hydrosoluble polymere, B = associative hydrophobic polymere), we showed that flower-like particles (BAB) are formed. Through the insertion of hydrophobic moieties in the associative block, dynamic and percolating tridimensional networks can be obtained, which properties depend on concentration and temperature (sol-gel transitions).  

Finally, we are interested in controlling the composition profile of copolymers incorporating acrylic acid units (AA). Combining the RAFT polymerization, performed in aqueous heterogeneous media with pH control helped us to demonstrate that it was possible to switch from one structure where the AA comonomer is distributed randomly to a gradient or even « block-like » structure.

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