The Structure of Water Bonded to Phosphate Groups at the Electrified Zwitterionic Phospholipid Membranes/Aqueous Interface.

Gaining insight into the water structure at the electrified phospholipid membranes/aqueous interface is vital and essential for elucidating the mechanism of many biochemical reactions, but still remains a formidable challenge. Herein, based on the superiority of surface enhanced infrared absorption (SEIRA) spectroscopy combined with electrochemistry in interfacial analysis, the evolution of local water structure at the zwitterionic phospholipid membranes/aqueous interface with an external electric field is revealed by means of ion perturbation. The strongly hydrogen-bonded water directly bonded to the phosphate groups (PO2 - ) has a strong mechanical strength to resist potential perturbations, and that portion of water greatly affects the electrostatic properties of the phospholipid membranes. This study innovates the basic understanding of electric double layer (EDL) at the membranes/aqueous interface.