Interfacial and confined water: Many-body cooperativity revealed by perturbation-resolved phonon Spectrometrics

Water at hydrophobic interfaces or confined in nanoscaled pores defies classical explanation, exhibiting anomalous phase behavior, transport, and thermodynamics. This perspective discusses these puzzles through the synergy of an integrated bond-order-length-strength and nonbonding electron polarization with hydrogen-bond cooperativity and polarizability framework (BOLS-NEP + HBCP). Coupled with high-resolution, perturbation-resolved spectroscopy (PRS), this report suggests that molecular undercoordination or hydrophobic confinement induces a supersolid-like interfacial phase that denotes polarization-induced structural ordering distinct from quantum supersolidity in ⁴He. This phase features shorter, stiffer HO bonds (with ∼3450 cm^-1 stretching vibrational frequencies), and exceptional properties like high elasticity, thermal stability, and enhanced chemical reactivity. The BOLS-NEP + HBCP model quantitatively explains anomalies-including ultrafast flow, supercooling, and the Mpemba effect-by linking coordination defects to bond relaxation and electron polarization. These insights support the concept of nanoscale water as a distinct, functional state, paving the way for applications in catalysis, nanofluidics, and sustainable energy technologies.