title: Solvent induced aggregation of protoporphyrin and octacarboxylphthalocyanine of zinc deposited on gold surface.
abstract: In this paper, we studied the influence of solvent on the morphology of zinc protoporphyrin and zinc octacarboxylphthalocyanine films transferred onto gold surface by dipping. In these films, carboxylic acid groups borne in periphery of macrocycles allow anchoring to gold via ionic interaction. First, we followed by UV-Visible absorption spectroscopy the solvation state of these conjugated macrocycles in pure DMF, in pure ethanol and in various ethanol/DMF mixtures. We show that the increase in ethanol proportion promotes interactions between macrocycles. Second, molecular layers of macrocycles spontaneously adsorbed from these various solutions onto gold surface were analyzed by ellipsometry, water contact angle measurements, UV-Visible absorption spectroscopy and atomic force microscopy. Results evidenced the layers were mainly composed of grains whose size of a few nanometers was directly related to the solvation conditions of molecules. In addition, Q band splitting was observed in the absorption spectrum of zinc octacarboxylphthalocyanine grain films which indicates specific organization of those molecules. Therefore solvent is shown to have a profound influence on the nanostructuration of as-prepared macrocycle layers on gold surface by promoting pre-organization in solution, and its composition enables to better control the morphology of those films by tuning the solubilization of macrocycles.
authors.affiliation: Aix-Marseille Université, IM2NP, Faculté des Sciences et Techniques, Campus de Saint-Jérôme, Avenue Escadrille Normandie Niemen, Case 142, F-13397 Marseille Cedex, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Gadenne
authors.forename: Mabinty
authors.initials: M
authors.lastname: Bayo-Bangoura
authors.forename: Louis
authors.initials: L
authors.lastname: Porte
authors.forename: Lionel
authors.initials: L
authors.lastname: Patrone
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D008567:Membranes, Artificial; D011524:Protoporphyrins / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties
chemical_list: D056831:Coordination Complexes; D007211:Indoles; D008567:Membranes, Artificial; D011524:Protoporphyrins; D012997:Solvents; C017803:zinc protoporphyrin; D006046:Gold