Direct measurement of acid-base interaction energy at solid interfaces.
We have studied acid-base interactions at solid-liquid and solid-solid interfaces using interface-sensitive sum frequency generation (SFG) spectroscopy. The shift of the sapphire hydroxyl peak in contact with several polar and nonpolar liquids and polymers was used to determine the interaction energy. The trend in the interaction energies cannot be explained by measuring only water contact angles. Molecular rearrangements at the sapphire interface, to maximize the interaction of the acid-base groups, play a dominant role, and these effects are not accounted for in the current theoretical models. These results provide important insights into understanding adhesion, friction, and wetting on solid interfaces.
Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States.
Anish
A
Kurian
Shishir
S
Prasad
Ali
A
Dhinojwala
D000388:Air; D000537:Aluminum Oxide / Q000737:chemistry; D002151:Calorimetry / Q000379:methods; D002621:Chemistry / Q000379:methods*; D006838:Hydrocarbons / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D006838:Hydrocarbons; D009930:Organic Chemicals; D011108:Polymers; D014867:Water; D000537:Aluminum Oxide