Electric field modulated configuration and orientation of aqueous molecule chains.

This article investigates how external electric fields (EFs), both direct-current (DC) and alternative-current (AC), influence the configuration and orientation of aqueous hydrophobic (n-triacontane) and hydrophilic (polyethylene glycol-10, PEG-10) oligomer chains using molecular dynamics simulations combined with diffusion maps (dMaps) machine learning for dimensionality reduction. The study finds that EFs modulate the free energy landscape to favor stretched molecular configurations aligned with the field, with DC EFs exerting a stronger effect than AC EFs, and hydrophobic n-triacontane showing greater sensitivity than hydrophilic PEG-10. Analysis reveals that EFs align water dipole moments and hydrogen bonds, promoting the formation of one-dimensional water nanowire structures that stabilize stretched and aligned oligomer conformations by minimizing disruption of these hydrogen bond networks. Comparisons with circularly polarized EFs indicate that directional EFs uniquely enhance hydrogen bonding and molecular alignment, counteracting typical hydrophobic collapse. These findings enhance understanding of EF-induced molecular behavior in aqueous environments and suggest potential applications in controlling biomolecules and polymers.