Fullerene films

The C-C linkage in tire polymeric [60]fullerene composite is highly unstable and, in turn, tire reversible [2+2] phototransfonnation leads to an almost quantitative recovery of tire crystalline fullerene. In contrast tire similarly conducted illumination of [70]fullerene films results in an irreversible and randomly occurring photodimerization. The important aspect which underlines tire markedly different reactivity of tire [60]fullerene polymer material relative to, for example, tire analogous [36]fullerene composites, is tire reversible transfomration of tire fomrer back to the initial fee phase. 

Bulhoes LOS, Obeng Y S and Bard A J 1993 Langmuir-Blodgett and electrochemical studies of fullerene films Chem. Mater. 5 110-14... 

Goldenberg L M 1994 Eleotroohemioal properties of Langmuir-Blodgett films J. Electroanal. Chem. 379 3-19 Chlistunoff J, Cliffel D and Bard A J 1995 Eleotroohemistry of fullerene films Thin Solid Films 257 166-84... 

In order to control the quantity of fullerene, contacting biological objects, FoS were obtained by evaporation of saturated solution of C60 in hexane introduced in the wells of 96-well culture plates ( Sarstedt ). Twenty-five microliters of solution was applied to each well and evaporated at 20-25 °C, after which the procedure was repeated several times to obtain a desirable concentration of fullerene (10, 20, and 30pg/cm2). Application of such volume allows obtaining a surface, covered with fullerene on the bottom and partly on the walls of a well at a high less than 2 mm. Microscopic investigations (optical and electronic microscopy) have shown that the surface was covered irregularly fullerene formed the isolated clusters, so that obtained fullerene films were not the real films, but rather isolated clusters of fullerene molecules (data not shown). However, it should be noted that their dimensions were smaller than those of cells and each cell covered several such clusters. 

However, fullerene C60-modified surface is adequate for the adhesion and normal growth of cells in culture. Cells of the line MA-104 in the Eagle-MEM medium formed on fullerene film a normal monolayer. Cellular viability was assessed with the resazurin (Alamar Blue) reduction test. The dye resazurin is reduced by mitochondrial dehydrogenases of viable cells into the fluorescent product resorufin (maximum X = 530 nm, max X = 590 nm). The intensity of... 

Thin fullerene films for laser protection can be obtained by incorporation or covalent attachment of fullerenes to transparent solid matrices. The optical limiting (OL) properties of Cgg originally detected in toluene solutions can be transferred to solid substrates without significant activity loss [27,143,144]. 

The formation of radiation defects under irradiation of the fullerene films by the bombarding particles leads to the essential modification of electronic subsystem, which determines their optical and electrophysical properties. However, the mechanisms of radiation defect formation with the use of different types of irradiation and dose load, and also the nature of a change in the electronic properties in this case are studied insufficiently. It is necessary to note that in the case of the condensed state of fullerenes not only the radiation damages of the molecular polyhedrons, which by themselves influence the redistribution of... 

Kunitsyn AE, Kozyrev SV, Novikov SV, Savel ev IG, Chaldyshev VV, Sharonova LV (1994) Production of Fullerene Films on GaAs Semiconducting Substrates, Phys Solid State 36 2573-2579... 

Su JS, Chen YF, Chiu KC (1999) Dielectric Properties of Fullerene Films, Appl Phys Lett 74(3) 439—441... 

The fullerenes, Cgo and C70, are produced in the laboratory by the contact arc-evaporation of 6 mm graphite rods (e.g. Johnson Matthey, spectroscopic grade) in 100 torr of helium in a water-cooled stainless steel chamber described previously [5]. The soluble material in the soot produced from the arc-evaporation is extracted with toluene using a Soxhlet apparatus. The pure fullerenes are obtained by chromatography on neutral alumina columns using hexanes as the eluant, or by the use of a simple filtration technique using charcoal-silica as the stationary phase and toluene as the eluant [5]. The fullerenes so prepared are characterized by UV/Vis spectroscopy and other techniques. FT-IR spectra of vacuum deposited fullerene films on KBr crystals also provide a means of characterization, just as do Raman spectra of films deposited on a silicon crystal. Ultraviolet and X-ray photoelectron spectra of fullerene films on... 

Figure 1. FT-ICR mass spectra of black mirrorlike sublimed fullerene film showing presence of (La C,) fullerenes. For the top panel the pulsed decelerator responsible for slowing the clusters down to be trapped in the analysis celt was optimized for the CM-C70 mass region. For the bottom panel it was optimized for the region around C. ...

This unique stability of a lanthanum-containing fullerene at 82 carbon atoms at First seems strange. For the normal, empty fullerenes the most abundant are usually 60,70,84, and to some extent 76, in decreasing order of apparent stability. When probing sublimed or solvent-deposited C, fullerene Films with this FT-ICR apparatus, this relative abundance pattern is readily seen. 

We note in passing that the recent transmission electron microscopy pictures of Cgo films by Wang and Buseck show evidence of Cjo-Cgo coalescence to form cylindrical bucky tubes in the solid Film, presumably triggered by the 400-keV electron beam. We wonder if metal atom encapsulation events would occur under similar circumstances with metal-doped fullerene films. 

For many optical limiting applications, solid films are desirable. Further work is underway to elucidate the response of fullerene films to optical pulses. ... 

One possible mechanism for the stabilization of sp chains in the carbon matrix may be the formation of joints between the chain ends and sp island adatoms. Jarrold and co-workers have reported the observation of ball-and-chain dimers formed by fullerenes linked by sp chains obtained by laser desorption of fullerene films [44]. The same type of connections could be formed in our films, rich of fullerene-like fragments [35], thus allowing the stabilization of the carbynoid species. Different type of stabilization sites could be present in our films since we observe a metastable decay of the carbynoid population. 

Simple redox solutes, ferrocene, N, N, N, JV-tetramethyl-l,4-phenylenediam-ine, decamethylferrocene, bis(i-propylcyclopentadienyl) iron(ll), [Ru(phen)j] (0104)2, [Fe(bpy)3](0104)2, [Co(bpy)3](0104)2, and iodine have been studied at electrodes modified with polymeric fullerene films. FuUerene-modified electrodes were prepared by electropolymerization of Cjq initiated by traces of dioxygen or by simultaneous electroreduction of fullerene and Pd(ll) acetate trimer. For the former films, the electrochemical activity decreases upon potential cycling. The electrochemical activity of the film is stabihzed by the redox solute added to the electropolimerization stage due to the catalytic oxidation of the fullerene film by the oxidized form of the redox system. Similarly, positively charged species can also be incorporated into the structure of the film. The reversible behavior of redox solutes decreases with the increase in the thickness of the Pd/C q film. This film also incorporates ferricinium ion, N, N, N, N-tetramethyl-l,4-phenylenediamine cation, decamethylferricinium ion, and to a smaller degree [Co(bpy)3]"+ [53]. 

Electrochemical reductions of fuUerene films in the presence of Brnsted acids yield hydrogenated fullerenes H Cgg, where n depends on the acid, its concentration, and on the electrode potential. Hydrogenated fullerene films behave as semiconductors with increased photoefficiency [67]. 

Zhokhavets Lf, Erb T, Gobsch G, Al-lbrahim M, Ambacher O (2006) Relation between absorption and crystallinity of poly(3-hexylthiophene)/fullerene films for plastic solar ceUs. Chem Phys Lett 418 343... 

In this study, we report on membrane properties of nonpolymerized and polymerized fullerene films grown on an organic polymer substrate (polycarbonatesyloxane) using a high vacuum deposition method. The gas permeability of the composite membranes to air constituents N2, O2 was studied. The stability of the membranes to ozone treatment was examined by Raman spectroscopy. The block with the composite fullerene membrane was testified as an element of the model ventilation-filtration-disinfection system. 

Fullerene is a promising material to be applied in membrane blocks for filtration systems because fullerene films possess a quasi-crystalline structure with pores whose dimensions are suitable for a gas separation. Our complex study is devoted to the development of a production technology of polymeric fullerene films and composite fullerene membranes and examination of their efficiency as a part of ventilation-filtration-disinfection systems. 

The intensity of the Ag pentagonal pinch mode which appears at 1468 cm"1 in the Raman spectra of pristine C6o is very sensitive to the presence of polymerized fullerene phases [1]. Raman spectra of the fullerene composite membranes (d - 0.5 pm) shown in Fig. 1 were obtained in the vicinity of this Ag mode (1468 cm 1) before and after the ozone treatment. The ozone treatment of the both nonpolymerized and polimerized fullerene films did not result in a... 

The membrane plate/block constructed from the fullerene film deposited on to the PCS substrate was tested in the model setup of the ventilation-filtration system shown in Fig. 2. The diameter of the working part of the membrane was about 14 mm. The model setup was constructed from brass. The setup is also equipped by front quartz window for the UV irradiation of the membrane. It was established that neither UV irradiation nor ozone treatment destroy the fullerene membrane. 

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