RAFT polymerisation of trifluoroethylene: the importance of understanding reverse additions

This article is the first report of the RAFT polymerisation of trifluoroethylene (TrFE). Trifluoroethylene is a rare but very important fluoromonomer, as it allows the preparation of materials endowed with unique electroactivity via copolymerisation with vinylidene fluoride (VDF) and other fluoromonomers. RAFT polymerisations carried out using O-ethyl-S-(1-methoxycarbonyl) ethyldithiocarbonate as a chain transfer agent and a thermal initiator were carefully examined. The polymerisation, its kinetics and the chain-end evolution were investigated by GPC, H-1{F-19} and F-19{H-1} NMR spectroscopy as well as MALDI-TOF mass spectrometry. Similar to the RAFT polymerisation of VDF, irreversible transfer reactions and reverse additions significantly affect the control of the polymerisation as well as the chain-end functionality. However, in contrast to VDF, unusual reverse propagation of TrFE, although limited to a few monomer units, was evidenced thanks to a combined NMR spectroscopy and DFT calculation approach. RAFT polymerisation afforded relatively well-defined PTrFE with a crystalline structure consistent with previous reports.

Automated summary

This article presents the first report on RAFT polymerisation of trifluoroethylene (TrFE), highlighting unique reverse propagation behavior compared to vinylidene fluoride (VDF). By examining the polymerisation process using various spectroscopic and mass spectrometric techniques, relatively well-defined PTrFE with crystalline structure consistent with previous reports was obtained.