# Why is fresh ice sticky?

Fresh ice cubes are almost instantly sticky and easily cling on to fabric and other similarly rough surfaces.

A few minutes later, however, the effect almost completely disappears.

• What is the cause of this adhesion?
• Why does the effect vanish after some time?
• something similar and intresting on Physics S.E. May 15 '15 at 16:47

Whether or not the ice cube will adhere to something is dependent on the temperature of the ice, the state of the surface of the ice, and the moisture content of the material.

The temperature of an ice cube can range from the freezing point of water ($0\ \mathrm{^\circ C}$) to well below this temperature. Typically most materials have a small degree of moisture regardless of whether they are “wet” or not. If the ice cube is cold enough, it will freeze the water present in the material. The giant covalent network structure of the ice extends into the material, accounting for why it sticks to the ice—the moisture in the material has become part of the ice cube.

If the surface of the ice cube is has melted, it will not be able to freeze the water in the material any more than it will be able to freeze the ice already melted on its surface. No giant covalent network solid will form, and the ice will not stick to the material.

• Do you have a reference for this? It seems perfectly plausible but I would be interested to see any studies of it.
– bon
May 15 '15 at 19:41
• I don't have any studies, but here is someone more qualified than me talking about it. Perhaps this would make for an interesting experiment though! You could try dipping ice at different temperatures in water for a small amount of time and analyze how its mass changes. May 15 '15 at 20:20
• Some proof that this effect depends more on the physics of heat exchange and presence of water in the target surface, rather than the specific usege of a chilled ice cube, is its generality; just about any very cold material tends to stick, be it a water ice cube, a dry ice ($\ce{CO2}$) cube, a chilled metal, etc, the last one being possibly the stickiest (be careful when experimenting!). I suspect atmospheric water freezing between two surfaces may play a role in certain circumstances, too. May 16 '15 at 14:33

What is the cause of this adhesion?

I propose a slightly different hypothesis from ringo. As opposed to the very cold ice freezing water in the material, I would presume the material to initially be dry, but at room temperature. This room temperature material may melt the outer layers of ice molecules, both cooling and wetting the material.

Then as the temperature equalizes, and the material does not further conduct heat into the wet areas, the wet material becomes cold enough to freeze again, creating the sticky effect you ask about.

Why does the effect vanish after some time?

The temperature gradient is not static, and the material will conduct some heat through it, so the sharp gradient that caused the melted ice to freeze again becomes a gradual gradient that shifts towards the center of the ice, and the water that refroze so quickly melts again, and the sides of the ice are no longer cold enough to refreeze any bits of them that happen to melt by exposure to a new contact surface.

Another characteristic of fresh ice is the supercooled vapor leaving the surface (sublimation.) This process supercools the surface of the ice keeping it well below the freezing point. When a warm object such as a towel or your skin condenses the vapor creating a thin layer of water on its surface which then freezes immediately on contact with the supercooled surface of the ice. The surface of the ice quickly warms at ambient temperature and the effect is lost.

• I find it hard to believe that sublimation cools faster that the external environment warms. May 18 '15 at 12:47