Two dimensional phase separation of diacetylenic matrix and glycolipids at the air–water interface

Abstract

The interaction between recognition elements (e.g., receptors) and the photochromic diacetylenic matrix is of great importance in biosensor preparation. The characterization of the miscibility or phase separation of functionalized components is an indispensable step for the design and preparation of biosensors. The interactions between 2,4-tricosadiynoic acid (TCDA) and dioctadecyl glycerylether-β-glucosides (DGG) as well as 10,12-pentacosadiynoic acid (PCDA) and DGG were studied by surface pressure-area isotherms and Brewster angle microscopy. It has been found that for a mixed TCDA–DGG monolayer on water subphase, there existed good miscibility of TCDA and DGG. On the contrary, in a mixed PCDA–DGG monolayer, the miscibility of PCDA and DGG is poor; PCDA molecules easily separated from the mixed PCDA–DGG monolayer during compression and formed a branch-like pattern. This result is consistent with the result obtained in π–A isotherm and is discussed based on the different position of the diacetylene group in the molecules.