Electrostatic assembly technique

Lev et al. have studied chemical methods to counteract nerve agents and remediate organophosphate (OP) contamination by means of nanoparticles, polymers, and nanofibers functionalized by a-nucleophilic agents [38, 39], Fibrous mats functionalized with a-nucleophilic oxime moieties were prepared by either electrospinning blends of polyacrylamidoxime and PAN or surface oximation of prefabricated PAN fibrous mats and demonstrated to possess a pronounced capability to hydrolyze chemical nerve agent simulants in the presence of moisture [39]. The layer-by-layer electrostatic assembly technique offers another strategy for electrospun fiber surface functionalization [40]. For the application in protective fabrics, Lee et al. demonstrated that electrospun fibers used as the substrate for titanium dioxide nanoparticle coatings resulted in increased specific substrate surface areas of about 10 that of the flat film, which enhanced photocatalytic decomposition of toxic industrial chemicals (Fig. 14.4a-c) [41,42]. 

In addition to the preparation of Langmuir and Langmuir-Blodgett films, the use of self-assembly techniques also plays an important role in the formation of particle films. Both physisorption, as, for example, electrostatic adsorption of charged particles from colloidal solution, and chemisorption onto a substrate have been investigated. In Section V.A, electrostatic adsorption will be reviewed chemisorption is the subject of Section V.B. 

Polyamidoamine (PAMAM) dendrimers (G3.5-G10) were used by Tsukruk et al. [25,26] to fabricate self-assembled monolayers by an electrostatic deposition techniques [27],... 

Fabrication of organic thin films based on sponfaneous molecular assembly has been considered as one of fhe powerful approaches to create novel supramolecular systems. In this context, multilayer films were fabricated by layer-by-layer electrostatic deposition techniques based on the electrostatic interaction between dsDNA and the positively charged polymer poly(diallyldimethylammonium chloride) (PDDA) on GC surfaces. A uniform assembly of PDDA/DNA multilayer films was achieved, based on the adsorption of the negatively charged DNA molecules on the positively charged substrate [55]. 

Electrostatic assembly, which involves attractive forces between two oppositely charged entities (polymers, nanoparticles, and substrates), has been proposed in the pioneering work of Her for the assembly of two- and three-dimensional structures.22 The LbL assembly of charged polyelectrolytes was later reported by Decher et al. for the fabrication of multilayer films of polyelectrolytes.10 23 Their technique is based on the consecutive adsorption of polyanions and polycations from dilute aqueous solutions onto a charged substrate (Fig. 13.2). 

In the next example (Example 2), a different approach for the preparation of zeolite films will be presented. This method was first proposed by Iler in 1979,11321 and involved the assembly of charged nano-sized particles layer by layer to form multilayer films based on electrostatic interaction, hence called the layer-by-layer (LBL) self-assembly technique. 

Electrostatic layer-by-layer (LBL) self-assembly techniques based on oppositely charged poipelectrolytes can be useful to create stable noncentrosymmetric order in thin films. Using this interesting technique, thermodynamically stable noncentrosymmetric multilayer films can be prepared without any need for poling. Tripathy et al. reported the fabrication stable multilayer films of epoxy-based side chain azo polymers for second-order nonlinear optics.The second-order NLO coefficients of the five-bilayer LBL films of these polymers were found to be comparable to those of spin-coated poled films. A schematic view of the procedure to fabricate polyelectrolyte-based LBL films is shown in Fig. 7. 

Preparation of multilayer composite surfaces prepared by electrostatic self-assembled technique for desalination of Fe and Fe ... 

In the present chapter layer-by-layer electrostatic self-assembly technique was used for the prep>aration of fxmctional polymeric membranes with metal ion removal capability. The fabrication process and properties of the resultant membranes were mentioned by using data of FT-IR spectra in detail. 

Prepared by an Electrostatic Self-Assembly Technique with Quaternary Ammonium Salt and Poly(acrylic acid) on Poly(acrylonitrile-co-acrylic acid) Membranes. /, Appl, Polym. Sci. Vol.llO, pp. 3234-3241. 

They decorated GO sheets with aerosol Ag nanocrystals using an electrostatic force directed assembly technique at room temperature [60]. 

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