Permanent Pores in Porous Liquids: Characterization, Simulation, and Experimental Studies

Porous liquids (PLs), as a novel functional material combining fluidic properties with permanent pore structures, exhibit unique advantages in fields such as separation and catalysis due to their uniquely tunable pore channel structures. The accurate characterization and quantitative analysis of pore structure and porosity are essential for optimizing the functional design and synthesis strategies of PLs. Various methods for characterizing and quantifying the pore characteristics of PLs have been reported, including positron annihilation lifetime spectroscopy, transmission electron microscopy, molecular dynamics simulation, gas absorption, density measurement, and so on. However, existing research sometimes fails to adequately account for pore characteristics, leading to methodological misuse and data bias. This study provides a systematic review of existing methods for studying the pore characteristics of PLs, categorizing them into three parts: analytical characterization, theoretical calculation, and experimental verification. Through a thorough analysis of the principles of various analytical techniques, this study clarifies the advantages and limitations of each method in analyzing pore characteristics, outlines the technical characteristics of different methods and establishes the applicability between different types of PLs to specific research methodologies. It is hoped that this study will provide more rigorous theoretical guidance for the study of the pore characteristics of PLs.