Heterocomplementary H-bonding RAFT Agents As Tools For The Preparation Of Supramolecular Star Polymers

In the present paper, supramolecular A3, miktoarm AB2and H type A2BA2stars were successfully synthesized by assembling Reversible Addition-Fragmentation Transfer (RAFT)-polymerized chains bearing hydrogen-bonding heterocomplementary associating units. The more detailed novelty of this investigate can be discribed as following:Thymine and diaminopyridine-functionalized chain transfer agents were designed to efficiently mediate the polymerization of vinyl acetate, methyl methacrylate, isoprene, styrene and BuA. The selective associations of the resulting hydrogen-bonding macromolecular building blocks were demonstrated by1H NMR in CDCI3solutions. AB2Miktoarm stars formation in the bulk was also confirmed by transmission electronic microscopy (TEM).The paper was composed of seven chapters:Chapter1:Review. Firstly summarize the background of supramolecular chemistry and present research, mainly focuses on the currently hot subject and the direction of development in the future. Secondly refers to the new controlled free radical polymerization--Reversible addition-fragmentation chain transfer (RAFT) polymerization, track the original and the development trend, as well as the restrict and the disadvantage currently. At last, based on supramolecular chemistry and RAFT polymerization, in order to exploit their own parricular advantages for mutual benefit and development, we combined both to generate new type polymers.Chapter2:Synthesise of chain transfert agents (CTAs). Aiming at generating well-defined supramolecular miktoarm stars, CTAs (R-S-C(=S)-Z) bearing heterocomplementary recognition units have been prepared:a thymine-functionalized xanthate, a thymine-functionalized dithiobenzoate, a thymine-functionalized trithiocarbonate and a DAP-functionalized dithiobenzoate. Those structures were confirmed by NMR and ESI-MS.Chapter3:Preparation of polymers. Thymine-functionalized xanthate was expected to efficiently mediate the radical polymerization of VAc, thymine-functionalized dithiobenzoate was expected to efficiently mediate the radical polymerization of MMA, thymine-functionalized trithiocarbonate was expected to efficiently mediate the radical polymerization of styrene and isoprene, DAP-functionalized dithiobenzoate was expected efficiently mediate the radical polymerization of styrene, respectively. The characterization of obtained polymers were performed by SEC, NMR and MALDI-TOF mass spectrometry.Chapter4. A3-type supramolecular polystyrene3-arms stars were successfully generated by RAFT-polymerized chains bearing hydrogen-bonding heterocomplementary associating units. The binding ability of the chains in solution was then demonstrated by1H NMR and SEC measurements, proving the formation of the A3-type supramolecular stars, after that, using titration experiments and a relevant mathematical model, binding constants were measured.Chapter5. Three different AB2-type supramolecular3-arms stars were successfully generated by RAFT-polymerized chains bearing hydrogen-bonding heterocomplementary associating units. The binding ability of the chains in solution was then demonstrated by’H NMR and SEC measurements, proving the formation of the A3-type supramolecular stars, after that, using titration experiments and a relevant mathematical model, binding constants were measured.Chapter6. H-shaped A2BA2-type supramolecular stars were successfully generated by RAFT-polymerized chains bearing hydrogen-bonding heterocomplementary associating units. The binding ability of the chains in solution was then demonstrated by’H NMR and SEC measurements, proving the formation of the A3-type supramolecular stars, after that, using titration experiments and a relevant mathematical model, binding constants were measured.Chapter7. Spectres. We provided the1H NMR and13C NMR of each CTA, as well as the blend of polymers which will be used to prepare AB2-type supramolecular3-arms stars.Conclusion and perspective. In summary, we have designed a series of original heterocomplementary H-bonding chain transfer agents allowing the generation of a panel of well-defined macromolecular building blocks with associating motifs located either at one chain end or in the middle of the chain. The self-assembly of these heterocomplementary H-bonding polymer chains afforded the straightforward generation of synthetically challenging supramolecular miktoarm stars. We envisage that this new category of RAFT agents would constitute a versatile platform for the design of a large array of tailored supramolecular polymers. In addition, the reversible nature of the association between the building blocks paves the way to new properties as compared to the covalent counterparts.