DIRECT OBSERVATION OF DOMAIN-STRUCTURE IN CONDENSED MONOLAYER PHASES

Fluorescence microscopy with polarized excitation allows regions of uniform tilt to be seen within domains of the liquid-condensed phase in monolayers of esters at the air/water interface, Transitions between a tilted and an untilted phase have been observed. Tilt regions within domains form regular six-arm patterns that are analogous to the star defect in films of liquid crystals. It is shown that six-arm stars are to be expected in these monolayers. A second transition has also been observed at lower temperatures.