Electrostatic self-assembly of sulfonated C-60-porphyrin complexes on chitosan thin films

Sulfonatcd C-60, 5,10,15,20-tetra kis 4-[meso-tetra-methyl (4-pyridinyl)] p orphyrin (C-60(SO3-)(n)-TMePyP4+) complex films have been prepared by elect rostatic self-assembly of each chromophore from solution. When these comple x films are formed on a thin film of chitosan polymer, the stacked bilayer films exhibit nearly twice the absorption as those prepared on conventional silanized substrates. X-ray photoelectron spectroscopy measurements disclo se a strong interaction between the C-60(SO3-)(n) and TMePyP4+. Atomic forc e microscopy results of the surface morphology, hardness, and the chemical functionality are used to explain the differences between substrate treatme nts. (C) 2000 Elsevier Science S.A. All rights reserved.