Surface phase behavior and domain topography of ascorbyl palmitate monolayers

LUCIANO A. BENEDINI; MARIA L. FANANI; BRUNO MAGGIO; NATALIA WILKE; PAULA MESSINA; SANTIAGO PALMA; PABLO SCHULZ

AMER CHEMICAL SOC

Año: 2011 vol. 27 p. 10914 - 10914

span style="FONT-FAMILY: "Arial","sans-serif"; FONT-SIZE: 12pt; mso-fareast-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ES; mso-bidi-language: AR-SA" lang="en">Ascorbyl palmitate (ASC16) is a molecule of potential pharmacological interest due to its antioxidant properties and amphiphilic nature. The surface behavior of ASC16 was studied using Langmuir monolayers and Brewster angle microscopy. This molecule formed stable monolayers at room temperature that showed phase transition from a liquid-expanded to liquid-condensed or crystalline phase, depending on the subphase conditions. Using a theoretical approach, we were able to explain the behavior of the ASC16 film at different bulk pH values and salt conditions based on the surface pH and the dissociation fraction of the film. Both condensed phases corresponded to highly packed conditions with the crystalline phase occurring at a low char