Structural properties of Langmuir-blodgett films containing amphipathic porphyrin and arachidic acid

Langmuir−Blodgett Films of Stearic Acid Containing Octakis((methoxycarbonyl)methyl)-meso- tetrakis(((eicosanyloxy)carbonyl)phenyl)porphyrin

“…The plateau indicates that the structure of the monolayer film at the air−water interface changes continuously. The NiLipoP−SA isotherm behavior is similar to that observed for several mixed lipid-dye monolayers, ,, such as the monolayer composed of zinc meso- tetrakis(eicosylpyridiumyl)porphyrin bromide and l -α-dimyristoylphosphatidylethanolamine (DMPE) observed by Flörsheimer and Möhwald, for which the plateau near 20 mN/m was described as a fluid−gel phase transition in which the porphyrin separates into the fluid lipid phase . Above 35 mN/m, catastrophic collapse of the monolayer occurs.…”

Effects of a central metal on the organization of 5,10,15,20-tetra-(p-chlorophenyl)–rare earth porphyrin hydroxyl compound at the air/water interface and in Langmuir–Blodgett films

“…Since metalloporphyrins often play crucial roles in making functional materials and also as models for some biochemical processes, much effort has been concentrated on the construction of thin metalloporphyrin films [1][2][3][4][5][6][7][8][9][10]. The fabrication of the thin metalloporphyrin films has usually been achieved with the Langmuir-Blodgett (LB) and self-assembly techniques.…”

Behaviour of the water-soluble meso-tetra(4-methylpyridyl)porphine in mixed monolayers and in Langmuir–Blodgett films

“…The area per PO2 at the lift off (335 A ˚2) compares well with the results obtained by Prieto et al 22 for the same porphyrin mixed with DMPA (L-a-dimyristoylphosphatidic acid) at 8 mN m À1 (320 A ˚2). The area per PO2 at the beginning of the transition (143 A ˚2) is smaller than the value expected for a single PO2 ring lying parallel to the interface (estimated values for the area of the porphyrin ring are about 200 A ˚2 by molecular models 13,16 and about 290 A ˚2 (ffi17 Â 17 A ˚2) by space filling 21 ). This value suggests the possibility of occurrence of some slipping and/or tilting of the PO2 rings during the compression of the expanded regime, resulting in porphyrin aggregation.…”

“…The monolayer stability can be achieved by increasing the hydrophobic component of the intermolecular forces, with alkyl chains covalently [9][10][11][12][13][14][15] or non-covalently attached to the porphyrin ring and/or with the addition of diluents with long hydrocarbon chains. [16][17][18][19] Furthermore, a synergistic stabilization is achieved when a charged porphyrin is mixed with oppositely charged lipids or surfactants. [20][21][22][23][24] Due to attractive electrostatic interactions, in addition to the hydrophobic component, there is often a strong condensing effect contributing to the monolayer stability.…”