Direct evidence for the gas phase thermal polymerization of styrene. Determination of the initiation mechanism and structures of the early oligomers by ion mobility.

We present here direct evidence for the thermal self-initiated polymerization of styrene in the gas phase and establish that the initiation process proceeds via essentially the same mechanism (the Mayo mechanism) as in condensed phase polymerization. Furthermore, we provide structural identifications of the dimers and trimers formed in the gas phase.