Crystalline Water at Room Temperature − Under Water and in Air

In a visionary work published in 1971, Albert Szent-Gyorgyi predicted that crystalline interfacial water layers would play a fundamental role in biological processes and evolution. However, interfacial water layers are so sensitive to observation that they have never been imaged on relevant surfaces, so far. Here we show that crystalline interfacial water layers prevail at room temperature on both hydrophilic and hydrophobic surfaces - in ambient air and subaquatically. We probe the interfacial water layers by monitoring the resonance frequency responses of quartz crystal microbalance sensors to their irradiation with 633 and 670 nm lasers. Our results are consistent with the fractional picture of confined water, previously explored by atomic force microscopy, near-field scanning optical microscopy, and atomic force acoustic microscopy. Since we provide both structural information and quantitative data on the thickness of interfacial water layers, our approach promises progress in biomedicine and life sciences.