a
Institute of Biophysics, University of Genoa, Corso Europa 30, 16132 Genova, Italy.b
Polo Nazionale Bioelettronica, Via Roma 28, 57030 Marciana (LI), Italy.Fabrication of multicomposite molecular assemblies of organic compounds on solids surfaces have been studied for more then 60 years. However, Langmuir-Blodgett technique and chemisorbtion from solution are limited to only certain classes of molecules. Self-assembled films fabricated through the sequential adsorption of polyanions and polycations is an alternative and more general approach.1,2 This technique had already been applied with materials like protein and colloids. Fabrication of homogeneous ultrathin film of conjugated polymer was done by self assembly technique.1,3 Sulfonated polyaniline (SPAn) is of interest because it is a highly conjugated, amphoteric macromolecules, where the magnitude and sign of charge may be manipulated through the control of the dopant concentrations and the pH of acqueous solutions. Self assembled multilayers were prepared by the sequential adsorption of polyelectrolyte and polyanions using same polymer (SPAn) at pH 5 and pH 10 respectively. The building up of such multilayers was characterized by the increment of adsorbed amount through UV-visible spectroscopy. A linear increase in the adsorption magnitude was measured from 2 to 25 bilayers. Films of this type are electrically active and electrochemical study was done. The built up multilayers were investigated by Brewster Angle Microscopy. Such Microscopy allowed one to observe the morphology of the films in respect with no multilayers as well as to reveal the 2D /3D features due to the fabrication techniques. As of today, the most advanced development of polyion based films is probably their potential for the fabrications of electronic applications such as electrocromic displays, microelectronics devices , biosensors, protective coating against corrosion and chemical sensor.
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