Organized multilayers of polydiacetylenes prepared by electrostatic self-assembly
Supramolecular Science 4(3-4): 471-477
New types of polydiacetylene multilayer are presented. The first type is based on electrostatic self-organization of diacetylene bolaamphiphiles and polyelectrolytes on a charged substrate followed by subsequent ultraviolet (UV) polymerization. The second type is prepared by direct adsorption of a water-soluble polydiacetylene and a polyelectrolyte in alternating sequence. The monomeric diacetylenes are of general formula X-(CH2)(9)-C=C-C=C-(CH2)(9)-X, with X being a sulfate (la), phosphate (2) or pyridinium (3) head group. The polydiacetylene (Ib) chosen for the multilayer is obtained by gamma irradiation of the corresponding diacetylene monomer la. It is found that all diacetylene derivatives are well suited for building up self-assembled multilayers and that two of the monomers (la, 2) can be polymerized on the substrate, while 3 is photo-inactive. The morphology of the multilayers is studied by scanning force microscopy and discussed. The smoothest surface topology is found for multilayers built up from the polydiacetylene Ib and a cationic polyelectrolyte in alternating sequence, while the largest unevenness is found when the anionic diacetylene la is alternatingly adsorbed with the cationic bolaamphiphile 3 followed by subsequent UV polymerization on the substrate. (C) 1997 Elsevier Science Ltd. All rights reserved.