Interactions between Acrylate/Methacrylate Biomaterials and Organic Foulants Evaluated by Molecular Dynamics Simulations of Simplified Binary Mixtures

Improving hydrophilicity is a key factor for enhancing the biocompatibility of polymer surfaces. Nevertheless, previous studies have reported that poly(2-methoxyethyl acrylate) (PMEA) surfaces demonstrate markedly better biocompatibility than more hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) surfaces. In this work, the origins of the excellent biocompatibility of the PMEA surface are investigated using molecular dynamics (MD) simulations of simplified binary mixtures of acrylate/methacrylate trimers and organic solvents, with n-nonane, 1,5-pentanediol, or 1-octanol serving as the probe organic foulants. The interactions between the acrylate/methacrylate trimers and solvent molecules were evaluated by calculating the radial distribution function (RDF), with the resulting curves indicating that the 2-methoxyethyl acrylate (MEA) trimer has a lower affinity for n-nonane molecules than the 2-hydroxyethyl methacrylate (HEMA) trimer. This result agrees with the experimental consensus that the biocompatibility of PMEA surfaces is better than that of PHEMA surfaces, supporting the hypothesis that the affinity between an acrylate/methacrylate trimer and a foulant molecule in a simplified binary mixture is a significant factor in determining a surface‘s antifouling properties. The RDF curves obtained for the other two solvent systems exhibited behavior that further highlighted the advantages of the PMEA surfaces as biocompatible polymers. In addition, the validity of employing the second virial coefficient (B2) as a predictor of antifouling properties was explored. The order of the B2 values of different binary mixtures indicated that the MEA trimers have the lowest affinities with n-nonane molecules, which confirms that although PMEA is more hydrophobic than PHEMA, it exhibits better biocompatibility. This analysis demonstrates that the MEA’s weaker miscibility with nonpolar foulants contributes to the excellent biocompatibility of PMEA. Thus, B2 is a promising criterion for assessing the miscibility between acrylate/methacrylate materials and nonpolar organic foulants, which indicates the potential for predicting the antifouling properties of acrylate/methacrylate polymer materials by evaluating the value of B2.