Langmuir-Blodgett films nanoparticles

B. Langmuir-Blodgett Films Containing Metallic Nanoparticles... 

Production of Metallic Nanoparticles Inside Langmuir-Blodgett Films... 

FIG. 13 Langmuir-Blodgett films of dioctadecyldimethylammonium bromide incorporating 6.0-nm-diameter CdS nanoparticles stabilized by 0.2 mM sodium hexametaphosphate. (a) Absorbance spectra for 2, 3, 4, 5, 6, 7, 8, and 13 layers (bottom to top) the inset shows the linearity of the absorbance at 450 nm versus the number of layers, (b) Fluorescence spectra (excitation wavelength = 400 nm) for 2, 3, 4, 6, 8, 13, and 18 layers (bottom to top) the inset shows the emission intensity at 480 nm versus the number of layers. (Reproduced with permission from Ref. 152. Copyright 1994 American Chemical Society.)... 

Tian Y, Fendler JH (1997) Langmuir-Blodgett film formation from fluorescence-activated, surfactant-capped size selected CdS nanoparticles spread on water surfaces. Chem Mater 8 969-974... 

Ravaine S, Fanned GE, Seip CT, Adair JH, Talham DR (1998) Photochemical generation of gold nanoparticles in Langmuir-Blodgett films. Langmuir 14 708-713... 

When some NC particles are surface treated to make them hydrophobic by, e.g., silylation and floated on the surface of water, a nanoparticle layer can be made on a solid substrate by a method similar to Langmuir-Blodgett film formation. Interparticle separation is well controlled by choosing an appropriate surface pressure prior to making LB film, as discussed next. 

Swami A, Kumar A, Selvakannan PR, Mandal S, Sastry M (2003) Langmuir-Blodgett films of laurylamine-modified hydrophobic gold nanoparticles organized at the air-water interface. J Colloid Interface Sci 260 367-373... 

Mayva K S ef a/1998 On the deposition of Langmuir-Blodgett films of Q-state CdS nanoparticles through electrostatic immobilization at the air-water interface Thin Solid Films Z 2 300... 

PANI/CSA, PTSA, PFOA nanorods, nanoparticles Cond. 53 = 0.91-0.97 52-120 s Langmuir-Blodgett films [31]... 

However, the above-mentioned reaction media represent only a small part of a large variety of colloidal particle preparation. In particular, one could cite, among others, physical vapor deposition, chemical vapor deposition, Langmuir-Blodgett films, polymer films [6-9], zeolite-entrapped nanoparticles [10], and supported catalysts [11]. 

Previously, Langmuir-Blodgett films of various nanoparticles such as Ag, Au, and CdS have been prepared. Typically, the surface of the nanocrystals are functionalized by organic molecules (usually long alkyl chains) in order to prevent particle aggregation and also to ensure the nanoparticles float on the subphase surface (usually water). The nanoparticles are dispersed in organic solvents such as toluene, and this solution is spread dropwise onto the subphase surface. 

Langmuir-Blodgett film transfer was used to prepare composites of GdS nanoparticles on Au substrates by Samokhvalov etal. [20]. Gharge transfer was observed using laser photochemical techniques. X-ray photoelectron spectroscopy (XPS) methods were used to study oxidation states. Photochemical studies... 

Guo, Q.J., Teng, X.W., Rahman, S and Yang, H. (2003) Patterned Langmuir-Blodgett films of monodisperse nanoparticles of iron, oxide using soft hthography. J. Am. Chem. Soc., 125,... 

A number of assembly methods employ self-assembly of nanoparticles at the air-water interface. Monolayers (and subsequent multilayers) can be formed at the interface due particle interaction and transferred to a solid substrate by controlled dip-coating and vertical deposition methods similar to Langmuir-Blodgett film deposition [81-86]. Regular monolayers of polymer colloids can also be assembled via an electrohydrodynamic route, whereby electrophoretically deposited particles between two electrodes can be manipulated to cluster in the presence of an electric field. On application of an AC or DC field, contrary to electrostatic norms, the like-charged particles are observed to coalesce producing large close-packed 2D crystalline domains [87]. 

This chapter covers the most recent advances in the chemistry of calixarenes and resorcinarenes and their self-assembly at interfaces developed after the excellent book chapter of Lucke, Stirling and Bohmer published in 2001 [11]. We focus the present work on calixarene- and resorcinarene-based Langmuir monolayers, Langmuir-Blodgett films, self-assembled monolayers (SAMs) on planar surfaces and on nanoparticles. This book chapter is not intended to be an exhaustive review of aU research works carried out on these topics selected illustrative examples are chosen in the vast available literature and discussed. The self-assembly of amphiphilic calixarenes in water has been reviewed elsewhere and will not be treated herein [12, 13]. 

Lee D K, Kang Y S, Lee C S and Stroeve P, Structure and characterization of nanocomposite Langmuir-Blodgett films of poly(maleic monoester)/Fe304 nanoparticle complexes , J Phys Chem B, 2002 106 (29), 7267-7271. 

It is well known that surfactants form several types of well-organized assemblies that provide specific size, geometrical control, and stabilization to particulate assemblies formed within the organized surfactant assemblies. The host surfactant assemblies that are available for the formation of nanoparticles are summarized in Table 1. The aqueous micellar solutions, reverse micelles, microemulsions, vesicles, monolayers, Langmuir-Blodgett films, and bilayer lipid membranes are typical surfactant assemblies that are often employed to prepare nanoparticles [9,10]. 

One of the new trends in chemical analysis appeared in the last decade is that the miniaturization. It becomes apparent in the miniaturization of analytical devices, separation procedures, measuring tools, analyzing samples and as a consequent the term micro have appeared. Further development of this trend have led to transfer from the term micro to nano one (nanoparticles, nanofluides, nanoprobes, nanoelectrodes, nanotubes, nanoscale, nanobarcode, nanoelectrospray, nanoreactors, etc). Thereupon a nanoscale films produced by Langmuir-Blodgett (LB) technique are proposed for modifying of chemical sensors. 

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. 

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