Electric fields at hydrophobic water interfaces: spectroscopic evidence, physical origin, and implications on reactivity

, corroborated by independent non-spectroscopic techniques, such as electrokinetic and surface charge measurements. The surprisingly close agreement among these different measurements and across broad experimental systems strongly hints at the existence of strong electric fields being a general feature of water-hydrophobe interfaces. We further discuss the physical origins of the interfacial electric field with a particular emphasis on the mechanism of preferential hydroxide accumulation at hydrophobic interfaces. Finally, we examine the implications of strong interfacial electric fields for chemical kinetics, radical generation and thermodynamics, thereby making important connections to interfacial water reactivity. These insights not only contribute to our fundamental understanding of water at interfaces but also point toward new strategies for harnessing interfacial water electrostatics in biomedicine, catalysis, green chemistry, and environmental science.