Quantum chemically calculated abraham parameters for quantifying and predicting polymer hydrophobicity.

Abstract

The leakage and accumulation of plastic in the environment is a significant and growing problem with numerous detrimental impacts and has led to a push toward the design and development of more environmentally benign materials. To this end we have developed a quantum chemistry (QC) based model for predicting the mobility of polymer materials from molecular structure. Hydrophobicity is used as a surrogate for mobility given that hydrophobic interactions drive much of the partitioning of contaminants in and out of various environmentally relevant compartments. To model polymer hydrophobicity we adjusted a previously developed Quantum Chemically Calculated Abraham Parameter (QCAP) model to calculate Abraham Parameters (AP) of small molecules from molecular structure information. The resulting model predicted the octanol-water partition coefficient (KOW) of polymer repeating units with a root mean square error (RMSE) of 0.48 (log scale). Additionally, the hydrophobicity of high molecular weight polymer materials was captured though solubility parameters and nile red staining experiments from the literature and predicted with RMSEs of 1.21 (J/cc)0.5 and 3.42 nm respectively. Finally, to test the environmental applicability of the model the relative adsorption capacity of three polymers were predicted and used to unify sorption isotherms across multiple sorbates and polymer sorbents.