Skin supersoliditymatters the performance and functionality of water droplets

Even more fascinating than its bulk parent,a water droplet possesses extraordinary catalytic and hydro-voltaic capability,elastic adaptivity,hydrophobicity,sensitivity,thermal stability,etc.,but the underlying mechanism is still elusive.We emphasize herewith that the H‒O bond follows the universal bond order‒length‒strength cor-relation and nonbonding electron polarization regulation and the hydrogen bond cooperativity and polarizability notion regulates the performance of the coupling hydrogen bond(O:H‒O).Computational and spectrometric evidence consistently shows that molecular undercoordination shortens the intramolecular H‒O bond by up to 10%while lengthening the intermolecular O:H nonbond by 20%cooperatively with an association of electron polarization,making the 0.3-nm thick droplet skin of a supersolid phase of self-electrification.The supersolid skin dictates the performance and functionality of the droplet in chemical,dielectric,electrical,mechanical,optical,and thermal properties as well as the transport dynamics of electrons and phonons.The amplification of these findings could deepen our insight into the undercoordi-nated aqueous systems,including bubbles and molecular clusters,and promote deep engineering of water and ice.