Langmuir-Blodgett patterning of phospholipid microstripes: Effect of the second component

Chen XD, Lu N, Zhang H, Hirtz M, Wu LX, Fuchs H, Chi LF

Abstract

We systematically describe the striped pattern formation of the mixed monolayers of 1.2-di(2,4-octadecadieiioyl)-sn-glycero-3-phosphocholine (DOEPC) and L-alpha-dipalmitoylphosphatidylcholine (DPPC) from the liquid expanded (LE) phase onto a mica surface by Langmuir-Blodgett (LB) transfer. The addition of the second component, DOEPC, strongly affects the formation of DPPC stripe patterns. When the molar ratio of DPPC and DOEPC is 1:0.1, the horizontal stripes dominate, while in the case of pure DPPC rnonolayer, there are three kinds of patterns: horizontal stripes, grids, and vertical stripes. The width and periodicity of stripes formed from the mixed monolayers are ca. 4-5 times smaller than those formed from pure DPPC patterns at the same transfer conditions, while the widths of channels are similar. A phase shift of substrate-mediated microphase separation in the two-component system during LB transfer is considered to be the mechanism for the influence of the second component on the formation of DPPC stripe patterns.