Determining Roles of Potassium-Feldspar Surface Characters in Affecting Ice Nucleation.

The roles of surface characteristics of the feldspar surface on ice nucleation have remained elusive. Here, simple strategies are reported to quantitatively analyze the effects of the surface morphology and molecular composition of the potassium-feldspar surface on ice nucleation. The steps are found to be responsible to the high ice nucleation efficacy according to the fact that water drop freezing temperature increases by about 4.5 °C atop the freshly cleavage feldspar surface being rich of steps comparing to the flattened ones. After the molecular component and atomic structure are destroyed by the fluorination, a tremendous decrease of the ice nucleation temperatures by around 9.0 °C is observed on both cleavage and flattened surfaces, and the steps still improve the ice nucleation activity of the hydrophobic cleavage surfaces. The influence of the surface composition also implies the importance of the molecular component and structure specificity on K-feldspar in facilitating ice nucleation.