기액계면에서 2,4-Hexadecadienoic Acid의 단분자막 거동에 대한 pH와 염의 영향

Abstract

The surface behavior of 2,4-hexadecadienoic acid (HDDA) on the air/water interface has been investigated on the effects of pH and salts. Since HDDA has a conjugated double bond, its π-A isotherm differs from that of palmitic acid. The HDDA monolayer exibited only the expanded phase and large limiting area because of the orientation caused by the diene group. The π-A isotherms, repetition effects and area change at constant π with pH indicated that the main factor of film loss was the dissolution rather than the film collapse of HDDA. Considering salt effects, Al3+ ion improved the monlayer stability by forming a stable surface structure of the film. Also the phase transition of film was observed. Perhaps it is because that diene group works as hydrophobic group by lifting a conjugated double bond from the water surface. However, Ba2+ did not show any effects, and Cd2+ accelerated the dissolution of monolayer into the subphase. In summary, the film loss by the dissolution and collapse could be reduced under the conditions of optimum pH, and the stability of monolayer was increased by the use of good salts.