6533b870fe1ef96bd12cf06c

RESEARCH PRODUCT

Polymorphic domains in monolayers of isomeric triple-chain phospholipids

subject

description

Monolayers of two isomeric branched chain phosphatidyl cholines at the air/water interface have been studied by means of fluorescence microscopy. The lipids differ in the position of the branched chain at the glycerol backbone and carry three chains per headgroup of almost equal length. Most qualitative features of the compression isotherms are similar except a difference of 4 A2/molecule in the minimum molecular area at high lateral pressures. This indicates a more condensed solid phase of compound C2 and is also reflected in the shapes of domains observed in the LE/LC phase coexistence range: domains with sharp edges and a mostly hexagonal shape are formed. On the other hand, the compound C1 with a larger limiting molecular area exhibits a smooth domain boundary and a shape instability as theoretically predicted.