FORMATION OF POLYION-COMPLEXED POLYDIACETYLENE ASSEMBLY AND ITS HE-NELASER-SIGNAL RESPONSES ON A PLASTIC OPTICAL-FIBER

A novel bilayer-forming polyion complex, consisting of a cationic diac etylene Lipid (1) and a polyanion (poly(styrene sulfonate), PSS) has b een assembled and immobilized on both a quartz plate and the core of a plastic optical fiber (POF), through which a He-Ne laser light passes continuously. The complexed cast film (1/PSS) shows a crystal-to-liqu id crystal phase transition due to an ordered multibilayer structure. Upon UV irradiation, the film can be readily polymerized and gives the blue form of polydiacetylene. It is noteworthy that the polymerized f ilm displays reversible thermochromism. Such polymerization and thermo chromic behaviors, observed spectroscopically, are successfully monito red as He-Ne laser-signal changes by the use of a POF system. This sys tem seems to have the ability to read out a more subtle molecular rear rangement in polydiacetylene assemblies as well as color changes due t o formation of the blue polymer or thermochromism, since the laser lig ht can draw information on refractive index of membrane phases. The pH responsiveness was also examined for a POF coated with the complexed film of a triblock polymer of PSS-block-poly(methacrylic acid)-block-P SS and 1. (C) 1998 Elsevier Science B.V. All rights reserved.