Predicting the suitability of aqueous solutions of deep eutectic solvents for preparation of bicontinuous porous carbons via spinodal decomposition processes

Abstract

Porous carbons are really interesting materials for applications such as gas adsorption, electrocatalysts or energy harvesting and conversion.[1] Among others, spinodal decomposition (SD) processes have proved effective for the synthesis of macro- and mesoporous materials.[2] Despite the theoretical aspects of SD processes are well understood, finding the proper experimental conditions to obtain bicontinuous structures via SD processes is a non-predictable and quite tedious process, typically based on trial and error. The challenge is therefore finding a ¿tool¿ capable to predict the suitability of a particular starting solution to undergo a spinodal decomposition process. We have used aqueous solutions of different DESs containing common carbon precursors (i. e. resorcinol) for the preparation of bicontinuous porous carbons via polycondensation of resorcinol with formaldehyde. Scanning electron microscopy analysis of the different carbons allowed us to determine which solutions leads to bicontinuous structures via SD. Moreover, we studied the starting DES/H2O binary mixtures by Brillouin spectroscopy given the capability of this technique to observe local structure rearrangements resulting from non-ideal mixing of the components. In our case, we found that the representation of data obtained by Brillouin spectroscopy allows predicting the range of molar fractions of DES in H2O for which bicontinuous structures via SD are ultimately obtained.