Ultrathin films preparation

Membrane Properties of p-222I. Copolyoxamide p-222I was selected for thorough study on the basis of encouraging results of measurements of transport parameters for this and related polymers. These results, obtained on ultrathin films prepared from trlfluoroacetlc acid solutions, are shown in Table II. 

A Ulman. An Introduction to Ultrathin Organic Films From Langmuir-Blodgett to Self-Assembly. Boston, Academic Press, 1991 JH Fendler. Nanoparticles and Nanostructured Films Preparation, Characterization and Application. Weinheim, Germany Wiley VCH, 1998. 

Torimoto T, Takabayashi S, Mori H, Kuwabata S (2002) Photoelectrochemical activities of ultrathin lead sulfide films prepared by electrochemical atomic layer epitaxy. J Electroanal Chem 522 33-39... 

Shuto, K., Oishi, Y, Kajiyama, T. and Han, C. C. (1993) Aggregation structure of a two-dimensional ultrathin polystyrene film prepared by the water casting method. Macromolecules, 26, 6589-6594. 

Recently, ultrathin evaporated films have been used as models for dispersed supported metal catalysts, the main object being the preparation of a catalyst where surface cleanliness and crystallite size and structure could be better controlled than in conventional supported catalysts. In ultrathin films of this type, an average metal density on the substrate equivalent to >0.02 monolayers has been used. The apparatus for this technique is shown schematically in Fig. 8 (27). It was designed to permit use under UHV conditions, and to avoid depositing the working film on top of an outgassing film. ... 

Mitzi, D. B. Kosbar, L. L. Murray, C. E. Copel, M. Afzah, A. 2004. High-mobihty ultrathin semiconducting films prepared by spin coating. Nature 428 299-303. 

Silica particles surface-imprinted with a TSA of a-chymotrypsin were applied for the enantio-selective hydrolyzation of amides. Surprisingly, the particles showed reverse enantio-selectivity, i. e., the sol-gel imprinted with the L-isomer of the enzyme s TSA showed a higher selectivity for the D-isomer of the substrate [125]. Also Ti02 gels have been imprinted, e.g., with 4-(4-propyloxypheny-lazo)benzoic acid. QCM coated with ultrathin films of this gel were prepared by an immersion process and showed selective binding of the template [ 126]. These examples demonstrate once more the broad applicability of the concept of molecular imprinting. 

Fig. 5 Surface plasmon microscopy images of a structured ultrathin PS film prepared by photopoiymerization through a mask A bare silicon appears dark, B polystyrene appears dark. (Reproduced with permission from [38] WUey)...

Controlled evaporation of SUVs and MLVs on substrates has been shown to result in the formation of ultrathin films which retained the regular bilayer structure of vesicles [69, 425-427]. These immobilized bilayers, termed as cast multibilayers , cast multibilayers , or ordered cast (ultrathin) films , have provided an alternative to LB films [425-446]. Alkylammonium surfactants with azobenzene (33) and glutamate (34) functionalities have been used, for example, in the preparation of cast-film-forming SUVs. X-ray diffraction... 

Ultrathin metal films, prepared either chemically or electroehemically, contain interconnected, roughened metal particles which can be exploited for catalysis, electron transfer, non-linear and surface-enhanced optics, and related applications. 

Research Focus Preparation of ultrathin films of anionic and cationic polymers. Originality Method for producing long-adhering chemically inert fabric modifiers. 

In situ polymerization, and electrochemical polymerization in particular [22], is an elegant procedure to form an ultra thin MIP film directly on the transducer surface. Electrochemical polymerization involves redox monomers that can be polymerized under galvanostatic, potentiostatic or potentiodynamic conditions that allow control of the properties of the MIP film being prepared. That is, the polymer thickness and its porosity can easily be adjusted with the amount of charge transferred as well as by selection of solvent and counter ions of suitable sizes, respectively. Except for template removal, this polymerization does not require any further film treatment and, in fact, the film can be applied directly. Formation of an ultrathin film of MIP is one of the attractive ways of chemosensor fabrication that avoids introduction of an excessive diffusion barrier for the analyte, thus improving chemosensor performance. This type of MIP is used to fabricate not only electrochemical [114] but also optical [59] and PZ [28] chemosensors. 

Preparation of enzyme-DNA films one layer at a time provides excellent control over the thickness of films designed to the specifications of the builder. Films containing two layers each of enzyme and DNA that are 20-40 nm thick are easily made. Alternate adsorption of layers of biomolecules and polyions is a general method that has been developed over the past decade by Lvov et al.[17 201 The technique has been used to make ultrathin films of a wide variety of proteins and oppositely charged... 

Sathaye, S. D. Patil, K. R. Paranjape, D. V. Mitra, A. Awate, S. V. Mandate, A. B. Preparation of Q-Cadmium Sulfide Ultrathin Films by a New Liquid-Liquid Interface Reaction Technique (LLRT). Langmuir2000, 16, 3487-3490,... 

Ultrathin oxide gel films prepared by the surface sol-gel process include many nano-sized voids, and the film density is generally low. Their compositions and... 

The electrical conductivity of the ultrathin oxide gel films prepared on an ITO electrode has been measured upon deposition of the aluminium electrode [18], Ti02-gel films with 4x2 mm size gave a resistance of 2.5 X 106 Q at 8.3 nm thickness and 0.61 X 106 Q at a thickness of 28 nm, respectively. The resistivity is independent of film thickness, and is 6-7 x 1010 Q-cm. An ln203-gel film of 41 nm thickness has a resistance of 24 Q, and the corresponding resistivity is calculated as 5 X 105 Q-cm. This value is smaller by a factor of 105 than that of TiOz-gel films. This difference in resistivity is close to that between TiOz crystal... 

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