Coil-to-Bridge Transitions of Self-Assembled Water Chains Observed in a Nanoscopic Meniscus.

Ten downward portions in the large oscillatory force-distance curve reported earlier are analyzed to understand a nanoscale water meniscus confined between a sharp probe and a flat substrate in air. The sigmoidal shape of each portion leads to the assumption that the meniscus is made up of independent transitions of two states: one for a coil state and the other for a bridge state. The analysis reveals that each downward portion occurs due to a coil-to-bridge transition of self-assembled water chains whose length ranges between 197 and 383 chain units. The transition provides novel insights into water's unique properties like high surface tension and the long-range condensation distances.