Polyelectrolytes multilayer

Lowack K and Helm C A 1998 Molecular mechanisms controlling the self-assembly process of polyelectrolyte multilayers Macromolecules 31 823-33... 

Shchukin DG, Ustinovich E, Sviridov DV, Lvov YM, Sukhorukov GB (2003) Photocatalytic microreactors based on Ti02-modilied polyelectrolyte multilayer capsules. Photochem Photobiol Sci 2 975-977... 

Mendelson, J., Barrett, C., Chan, V., Pal, A., Mayes, A. and Rubner, M. (2000) Fabrication of microporous thin films from polyelectrolyte multilayers. Langmuir, 16, 5017—5023. 

Elbert DL, Herbert CB, Hubbell JA (1999) Thin polymer layers formed by polyelectrolyte multilayer techniques on biological surfaces. Langmuir 15 5355-5362... 

Ng V, PI G, Ss S-C et al (2007) Nanoencapsulation of stem cells within polyelectrolyte multilayer shells. Macromol Biosci 7 877-882... 

The low nonspecificity of PEG layers also was used to eliminate biomolecule binding to certain areas of an array. Kidambi et al. (2004) patterned an mPEG-carboxylate molecule onto polyelectrolyte multilayers to mask portions of the surface. The extremely low binding character of PEG provides advantages for creating patterned surfaces that other modifiers using aliphatic alkyl linkers do not provide. 

Kidambi, S., Chan, C., and Lee, I. (2004) Selective depositions on polyelectrolyte multilayers Self-assembled monolayers of m-dPEG acid as molecular template./. Am. Chem. Soc. 126, 4697-4703. 

The preparation of the FEDs, the experimental set-up and measuring conditions for the detection of DNA immobilization and hybridization as well as for the monitoring of the layer-by-layer adsorption of the polyelectrolyte multilayers are described in detail elsewhere [46-50], The attachment of these charged macromolecules to the FED surfaces has been systematically characterized by means of capacitance-voltage,... 

P.A. Neff, A. Naji, C. Ecker, B. Nickel, R. Klitzing, and A.R. Bausch, Electrical detection of self-assembled polyelectrolyte multilayers by a thin film resistor. Macromolecules 39, 463 466 (2006). 

M. Schonhoff, Self-assembled polyelectrolyte multilayers. Curr. Opin. Coll. Interface Sci. 8, 86-95... 

In recent years, the measurement of thick adlayers has received an increasing interest in the field of so-called polyelectrolyte multilayer films. These films sometimes have a thickness of several micrometers. Such large thicknesses are obviously not easily monitored using conventional waveguide sensors because of the limited penetration depth into the adlayer. Simply, waveguide sensors loses their sensitivity when the adsorbed layer thickness exceeds 2 3 times the penetration depth of the evanescent field and cannot be used to monitor films thicker than 350 nm12. 

Horvath, R. Pedersen, H. C. Cuisinier, F. J. G., Guided wave sensing of polyelectrolyte multilayers, Appl. Phys. Lett. 2006, 88, 111102 111104... 

Dai J, Baker GL, Bruening ML (2006) Use of porous membranes modified with polyelectrolyte multilayers as substrates for protein arrays with low nonspecific binding. Anal Chem 78 135-140... 

Although the majority of chiral CEC—MS applications still involve packed columns, few reports on chiral OT-CEC-MS are found in recent literature. The feasibility of coupling OT-CEC (using a short Chirasil-Dex-coated capillary column) to MS and MS/MS for trace analysis of hexobarbital enantiomers in biological fluids was reported by Schurig and Mayer. More recently, Kamande et al. investigated polyelectrolyte multilayer (PEM) coating as a new medium for the separation of chiral analytes, and PEM-coated capillaries were successfully coupled to ESI/MS for the stereoselective analysis of five /1-blockers. 

Kamande, M. W., Zhu, X., Kapnissi-Christodoulou, C., and Warner, 1. M. (2004). Chiral separations using a polypeptide and polymeric dipeptide surfactant polyelectrolyte multilayer coating in open-tubular capillary electrochromatography. Anal. Chem. 76, 6681—6692. 

Polyelectrolyte complexes formed by polyion pairing are of special interest, including protein-polyelectrolyte interactions such as protein-DNA complexes. A special case of polyelectrolyte complexes are polyelectrolyte multilayers (PEM) on surfaces formed by ion pairing, van der Waals interactions and counterion release of oppositely charged polyelectrolytes [2, 3]. 

In this chapter we describe the use of polyelectrolytes carrying redox-active centers on electrode surfaces with particular emphasis on organized layer-by-layer redox polyelectrolyte multilayers (RPEM). In redox-active polyelectrolyte multilayers the polyion-polyion intrinsic charge compensation can be broken by ion exchange driven by the electrochemical oxidation and reduction forming extrinsic polyion-counterion pairing. In this chapter we describe the structure, dynamics and applications of these systems. 

The inner structure of polyelectrolyte multilayer films has been studied by neutron and X-ray reflectivity experiments by intercalating deuterated PSS into a nondeut-erated PSS/PAH assembly [94, 99]. An important lesson from these experiments is that polyelectrolytes in PEMs do not present well-defined layers but are rather interpenetrated or fussy systems. As a consequence, polyelectrolyte chains deposited in an adsorption step are intertwined with those deposited in the three or four previous adsorption cycles. When polyelectrolyte mobility is increased by immersion in NaCl 0.8 M, the interpenetration increases with time as the system evolves towards a fully mixed state in order to maximize its entropy ]100]. From the point of view of redox PEMs, polyelectrolyte interpenetration is advantageous in the sense that two layers of a redox polyelectrolyte can be in electrochemical contact even if they are separated by one or more layers of an electroinactive poly ion. For example, electrical connectivity between a layer of a redox polymer and the electrode is maintained even when separated by up to 2.5 insulating bUayers [67, 101-103]. 

We will discuss here applications of polyelectrolyte-modified electrodes, with particular emphasis on layer-by-layer self-assembled redox polyelectrolyte multilayers. The method offers a series of advantages over traditional technologies to construct integrated electrochemical devices with technological applications in biosensors, electrochromic, electrocatalysis, corrosion prevention, nanofiltration, fuel-cell membranes, and so on. 

Equations 2.26 and 2.27 carmot be solved analytically except for a series of limiting cases considered by Bartlett and Pratt [147,192]. Since fine control of film thickness and organization can be achieved with LbL self-assembled enzyme polyelectrolyte multilayers, these different cases of the kinetic case-diagram for amperometric enzyme electrodes could be tested [147]. For the enzyme multilayer with entrapped mediator in the mediator-limited kinetics (enzyme-mediator reaction rate-determining step), two kinetic cases deserve consideration in this system in both cases I and II, there is no substrate dependence since the kinetics are mediator limited and the current is potential dependent, since the mediator concentration is potential dependent. Since diffusion is fast as compared to enzyme kinetics, mediator and substrate are both approximately at their bulk concentrations throughout the film in case I. The current is first order in both mediator and enzyme concentration and k, the enzyme reoxidation rate. It increases linearly with film thickness since there is no... 

Nolle AJ, Cohen RE, Rubner ME (2006) A two-plate buckling technique for thin film modulus measurements applications to polyelectrolyte multilayers. Macromolecules 39 4841-4847... 

Nolle AJ, Rubner MF, Cohen RE (2005) Determining the Young s modulus of polyelectrolyte multilayer films via stress-induced mechanical buckling instabilities. Macromolecules 38 5367-5370... 

Park J, Hammond PT. Multilayer transfer printing for polyelectrolyte multilayer patterning direct transfer of layer-hy-layer assembled micropattemed thin films. Adv Mater 2004 16 520-525. 

Zheng HP, Lee 1, Rubner MF, Hammond PT. Two component particle arrays on patterned polyelectrolyte multilayer templates. Adv Mater 2002 14 569-572. 

Caruso F, Yang WJ, Trau D, Renneberg R. Microencapsulation of uncharged low molecular weight organic materials by polyelectrolyte multilayer self-assembly. Langmuir 2000 16 8932-8936. 

Gao CY, Liu XY, Shen JC, Mohwald H. Spontaneous deposition of horseradish peroxidase into polyelectrolyte multilayer capsules to improve its activity and stability. Chem Commun 2002 1928-1929. 

A cell with a small Pt disk working electrode coated with a polyelectrolyte multilayer made of poly(allylamine)-poly(vinyl sulfate), a Pt wire counterelectrode and a reference SCSE may be used for selective amperometric determination of H2O2, in the presence of ascorbic acid (22), uric acid (29) and acetaminophen (148). The latter three compounds show a significant response with the bare working electrode at +0.6 V while a practically nil one with the coated electrode. The reason for this selectivity may be an exclusion effect by the coating. ... 

Polyelectrolyte Multilayers" Dynamic Contact Angle Advancing Contact Angle... 

Selected polyelectrolyte multilayers were prepared and their thickness and refractive indices measured using ellipsometry. Testing results are reported in Table 2. 

M. W. Kamande, X. Zhu, C. Kapnissi-Christodoulou, and 1. M. Warner, Chiral Separations Using a Polypeptide and Polymeric Dipeptide Surfactant Polyelectrolyte Multilayer Coating in Open-Tubular Capillary Electrochromatography, Anal. Chem. 2004, 76, 6681. 

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