Reduction of ice adhesion to metal by using self-assembling monolayers (SAMs)

A new method has been developed to study the role of hydrogen bonding in ice adhesion and to minimize the effect of this mechanism on ice adhesion. Metals were coated with a mono-molecular layer that had either strong hydrophobic properties or strong hydrophilic properties. Self-assembling monolayers (SAMs) of varying degrees of hydrophobicity/hydrophilicity were created by mixing the hydrophobic and hydrophilic components. The SAM structure and quality were examined using atomic force microscopy, and the degree of the SAM hydrophobicity/hydrophilicity was characterized by the contact angle of water on the monolayer surfaces. Then, water was frozen on the top of the SAM and the shear strength of the interface between ice and SAM was measured. A good correlation between the contact angle of water and the ice adhesion strength was shown and the fraction of ice adhesion caused by hydrogen bonding was determined. It is revealed that hydrogen bonding significantly enhances ice adhesion.