Adsorption sequential electrostatic

The direct LbL assembly of oppositely charged nanoparticles, which did not involve polyelectrolytes, was also examined. Sastry et al. demonstrated the formation of alternating layers of gold and silver nanoparticles via sequential electrostatic assembly.36 In the absence of polyelectrolytes, the effective charging of gold and silver nanoparticles was accomplished by the adsorption of 4-aminothiophenol and 4-carboxythiophenol molecules on the nanoparticle surfaces, respectively. The multilayer films were stable up to 100°C. 

The majority of LbL systems employ oppositely charged polyelectrolytes for the adsorption of polymer layers driven by electrostatic forces (Fig. 1). The assembly relies on the sequential reversal of charge upon the adsorption of oppositely charged polyelectrolytes. Polyelectrolytes may be classified as either strong or weak, with the former maintaining its charge independent of the pH, while the latter exhibits pH-dependent charge due to the presence of ionizable moieties. One of the most... 

Bian S, He J A, Li L, Kumar J, Tripathy SK. 2000. Large photoinduced birefringence in Azo dye/polyion films assembled by electrostatic sequential adsorption. Adv Mater 12(16) 1202 1205. 

A key application for these materials involves the creation of electrostatic superlattices by layer-by-layer assembly [135-138]. The technique involves the sequential adsorption of polycationic and polyanionic monolayers from aqueous solutions to form nanoscale multilayer polymer films of controlled thickness. Such film architectures can be manipulated to achieve unique physical properties, and orchestrated for the construction of a range of devices. For example, well-characterized organic/organo-metallic polymer electrostatic superlattices have been prepared by alternate adsorp-... 

It is known that interfacial rheology of protein-surfactant mixed layers depends on the protein (random or globular), the surfactant (water-soluble or oil-soluble surfactant, ionic or non-ionic), the interface (air-water or oil-water), the interfacial (protein/surfactant ratio) and bulk (i.e., pH, ionic strength, etc.) compositions, the method of formation of the interfacial layer (by spreading or adsorption, either sequentially or simultaneously), the interactions (hydrophobic and/or electrostatic), and the displacement of protein by surfactant [7],... 

The polyelectrolyte multilayer films were prepared using the layer-by-layer (LbL) technique of electrostatically driven sequential adsorption of polyions from their solutions. The technique is described in details elsewhere [1,17]. Adsorption of polyelectrolytes was performed from solutions of NaCl in H2O of concentration 0.15 M at PE concentration of 0.5 g/1. Each deposition step lasted 20 min and rinsing in between the steps was done 3 times for 2 min in water. Always ultra pure water with Milli-Q quality was used. Ready samples were rinsed with D2O before the NR experiments. 

The theoretical approaches aimed at a description of nonlinear adsorption regimes are discussed next—in particular the elassieal, random sequential adsorption (RSA) model. The role of polydispersity, particle shape, orientation, and electrostatic interactions is elucidated. Then, the generalized RSA model is presented, which reflects the coupling of the surface transport with the bulk transfer step governed by external force or diffusion. 

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