Enhancing the pre-polymerization coordination of 1-vinylimidazole

• The polymerization of 1-vinylimidazole is found to be enhanced with LiTf2N addition.
• Molecular dynamic simulations are used to analyze the structure of these mixtures.
• The local coordination of key reaction sites is found to be enriched by the LiTf2N.
• The experimental reaction enhancement is attributed to local coordination effects.

Recent experimental investigations have found that the rate and conversion of the photopolymerization of 1-vinylimidazole (VIm) can be significantly accelerated with the addition of lithium bistriflimide (LiTf2N). However, the underlying molecular-level interactions responsible for this phenomenon are unclear. The two components, VIm and LiTf2N, are miscible over a wide range of concentrations and form liquid phases at ambient temperature, and if the fundamental behavior of this mixture can be clearly quantified, there are significant opportunities for tuning the polymerization dynamics, polymer structure, and properties. In this work, molecular dynamics (MD) simulations are used to model the underlying pre-polymerization structure of VIm+LiTf2N mixtures at several different concentrations. It is found that the Li+ enhances the site–site interactions of key functional groups involved in the polymerization, and this is suggested to play a major role in the experimentally-observed enhancement of the polymerization behavior.

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