HydroLayer Calculator: A Pseudo-Parallel Tool for Rapid Hydration Layer Structure Calculation in MD Simulations via VMD

Hydration plays a crucial role in the performance of hydrophilic materials, influencing properties such as fouling resistance and lubrication. Characterizing the parameters of the hydration layer is essential to understanding these behaviors. In this study, we developed the HydroLayer Calculator, a multiparameter analysis tool based on Tcl, designed to calculate six key parameters of the hydration layer along the radial direction of the reference atoms using VMD: radial distribution function (RDF), orientation distribution function (ODF), hydrogen bond (HB) structure, mean square displacement (MSD), mean residence time (MRT), and water binding sites (WBS). An innovative pseudoparallel computing method is introduced to significantly enhance computational efficiency while addressing the limitations of existing single-function tools. Application of the tool to molecular dynamics simulations of carboxyethyl methacrylate (CEMA), 2-hydroxyethyl methacrylate (HEMA), glycidyl methacrylate (GMA), and bulk water systems revealed distinct differences in hydration layer dynamics on various surfaces. The tool features a user-friendly modular architecture, supports custom parameter extensions, and can be applied to a wide range of molecular systems and parameter calculations. The HydroLayer Calculator offers significant benefits for researchers studying hydration layers.