Quantitative Criteria for Solvent Selection in Liquid-Phase Exfoliation: Balancing Exfoliation and Stabilization Efficiency

The selection of solvent is pivotal in liquid-phase exfoliation (LPE), as an ideal solvent minimizes the energy required to disrupt the interlayer attractive interactions while stabilizing exfoliated layers to prevent re-agglomeration. This study theoretically analyzed the LPE of Mg(OH)₂ in different solvents, including water, dimethyl sulfoxide (DMSO), dimethylformamide, N-methyl-2-pyrrolidone (NMP), isopropyl alcohol, and 2-butanone, through first-principles calculations combined with experimental validation. DMSO was identified as the most effective solvent for reducing the interlayer attraction, based on exfoliation energy calculations, while NMP was the most efficient for stabilizing exfoliated layers, based on binding energy assessments. Principal component analysis of the solvents' physicochemical properties reduced the original dataset of seven variables to two dominant factors. The binding energy correlates with planarity and polarity, whereas the exfoliation energy is governed by dipole moment and polarity. The biaxial straining theory successfully clarified the underlying mechanisms behind the established criteria for selecting the optimal solvent. Experimental results confirmed that DMSO outperforms water in the LPE of Mg(OH)₂. These results establish a quantitative framework for solvent selection, enhancing the efficiency of the LPE processes.