Topic 1: Design of ionic liquids

Synthesis and characterisation of the chemical and physico-chemical properties of ionic liquids for their association with polymer media

Leaders: Daniel Lemordant, Catherine Santini, Mireille Turmine

The aim of this research topic will be to compile a database of different ionic liquids, both the commonly found ones in addition to those synthesised on a customised basis. For this reason, all of the intrinsic parameters of the liquids concerned (viscosity, mass per unit volumes, surfaces tensions, activities, etc.) shall be pooled in addition to the values of parameters that come directly into play in chemical reactions in an organic medium (scales of acidity, electrochemical windows, solubilities, etc.). In this topic, we shall be interested in the physico-chemical behaviours of protic and non-protic ionic liquids, both pure and in mixtures with molecular solvents or monomers, as reaction media for macro-molecular chemistry and electro-chemistry. The behaviour of supra-molecular edifices in these media (micelles of charged and uncharged surface-active agents in addition to their mixtures, interactions between surface-active agents and polymers) shall be discussed. The idea is to build up a library of chemical, physico-chemical and thermodynamic data for a wide range of ionic liquids which will act as a storehouse of the information required in order to understand and establish relationships between the chemical structure of ionic liquids and their impact on the polymer materials with which they may be associated.

Within this topic, one of the challenges that must be overcome concerns the toxicity of ionic liquids. Indeed, ILs attract attention due to their potential for use as green solvents, thanks in particular to their negligible vapour pressure and high thermal stability. However, their synthesis involves reactants that have non-negligible environmental impacts, which undermines their image as green solvents. Thought must therefore be given to implementing environmentally friendly synthesis processes for non-toxic and biodegradable ionic liquids that conform to the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations. The use of the C02 medium in supercritical conditions is an avenue worth exploring given the solubility of ionic liquids in carbon dioxide in the field of “supercritical” states. The purification and regeneration of ionic liquids shall also be covered.

Summary of the different scientific obstacles addressed in this first topic:

• Synthesis of ILs with a view to their association with polymers
• Identification of thermodynamic and physico-chemical properties (viscosity, surface tension, etc.)
• Association operating in this field.
• Study of the behaviour of ILs in a reactive medium (macro-molecular chemistry and electro-chemistry)
• Modelling of the properties of ILs
• Understanding of interactions between ILs/polymers
• Relationships between structure/combination (cation, anion, functionalisation) and properties of the material
• Stability, toxicity and (bio)degradation of ILs
• Purification/regeneration of ILs
• Solubilisation of polymer/solvent

The teams of chemists participating in this research topic cover all of the competences and expertise required for the successful exploitation of this topic. They are presented in Table 1.

Tableau 1. Research teams involved in topic #1.