Ice growth kinetics and quasi-liquid layer thickness as revealed by environmental AFM

CONSTANTIN, JULIÁN GELMAN; M. PAULA LONGINOTTI; GIANETTI, MELISA M.; PABLO G. DEBENEDETTI; CORTI, HORACIO R.

Ciudad Autónoma de Buenos Aires

Workshop; Structure and Dynamics of Glassy, Supercooled and Nanoconfined Fluids; 2019

CNEA-ANPCYT

Theexistence of a QLL at the ice?air interface has been thoroughlydiscussed in the literature, mainly considering that this layer playsan important role in the flow behavior of ice and snow, theadsorption of substances onto ice, and the low friction of solids onice. Moreover, icecrystal growth from the vapor phase is an important microphysicalprocess critical for the evolution of atmospheric cold clouds. Therates of water condensation and evaporation on atmospheric particlesinfluence the lifetime properties of clouds, and thereby affect theatmosphere?s radiation budget, the formation of precipitation andweather. Quantitative understanding of both the QLL thickness and thekinetics of ice growth are extremely important for atmosphericscience, being also crucial for many industrial processes. Forexample, multiphase modeling of gas phase reactions, photolysisreactions and aqueous reactions in suspended aerosol particles dependon the QLL thickness.Therefore, inthis work we will show an environmental atomic force microscopy (AFM)technique developed in our group to measure the quasi-liquid layer(QLL) thickness of ice and the kinetics of ice growth from the vaporphase under humidity and temperature-controlled conditions. Bothquantities were studied by measuring force curves over pure icedeposited on mica under equilibrium and non-equilibrium conditions,respectively. Our resultssuggest a QLL thickness lower than 1 nm in the temperature rangebetween -7 and -2 ºC, that is in the lower-bound of otherexperimental determinations. This suggests that other authorsoverestimated the QLL thicknesses due to temperature gradients andindentation of ice. In addition, this experimental technique allowedobtaining more reliable ice growth rates, since temperature andhumidity were controlled close to the ice nucleation centers avoidingsystematic errors.p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 115%; text-align: left; }p.western { font-family: "Liberation Serif", serif; font-size: 12pt; }p.cjk { font-family: "Noto Sans CJK SC Regular"; font-size: 12pt; }p.ctl { font-family: "FreeSans"; font-size: 12pt; }