MACROSCOPIC AND MICROSCOPIC SURFACE CHARACTERIZATION OF A VITAMIN-K-1MONOLAYER ON WATER

Film pressure and surface potential measurements are used to elucidate chain orientational changes in vitamin K-1 and phytol monolayers duri ng compression and expansion cycles. Second harmonic generation studie s on vitamin K-1 show a major reorientation in the quinone head group during compression. In the expanded film, phytol chains are freely rot ating and head groups are randomly oriented. Upon compression, the sho rt axis of the quinone head groups orients with a tilt angle of 24 deg rees to the surface normal. Molecular interactions may cause the surfa ce potential to change as chains become more nearly vertically oriente d.