Revealing Microplastic-Water Interactions in the Atmosphere Via Coarse-Grained Simulations

Microplastics have emerged as a significant environmental concern due to their global presence. Recently, microplastic particles have been discovered in the atmosphere, though their atmospheric assembly behavior and possible impacts on climate processes is largely unknown. In this work, we study the potential effects of atmospheric microplastics on climate using molecular dynamics simulations. In particular, we aim to understand how the presence of microplastic particles may affect water phase behavior and droplet nucleation, relevant to cloud dynamics and precipitation. We pair the ML-BOP coarse-grained water model with typical bead-spring polymers to provide a preliminary look at water-microplastic interactions. First, we show that ML-BOP, despite being designed to model water’s condensed phases, reasonably predicts water’s liquid-vapor phase behavior. We then simulate ML-BOP in the presence of polymers of varying hydrophobicity to evaluate the polymers’ impact on water phase behavior and liquid droplet nucleation. Understanding such interactions is crucial for predicting climate trends and developing strategies to mitigate the global impact of microplastic pollution.