Large domains in a diacetylene derivative (10, 12-pentacosadiynoic aci
d) monomer monolayer at the air-water interface were obtained by sprea
ding a solution of relatively high concentration. Uniformly oriented l
arge domains of over 20 mm x 5 mm were prepared when the area of water
surface was slowly increased by moving a barrier after the highly con
centrated solution was spread on a small bounded water surface.