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The polyelectrolyte multilayer films created by alternating adsorption of polyanions and polycations from aqueous solution were subjected to standing-wave X-ray fluorescence to calculate the ion concentration and ion profile. The findings suggested that the nature of charge of the outermost layer and the washing procedure used in the end decide the concentration and profile of the ion.

A molecular dynamics simulation study of hydrated Nafion at water contents is performed to examine the structure and dynamics of the hydrated polyelectrolyte system. The results have shown that both the local structure of the poorly hydrated hydronium ions and the disconnected nature of the global morphology of the water nanonetwork at low water content have contributed to poor conductivity.

The adsorption of polyelectrolytes at oppositely charged surfaces is experimentally studied. The polymer surface coverage, [Gamma], at equilibrium is measured by two reflectivity techniques, ellipsometry and polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS), as a function of the surface charge density [sigma], and of the polymer ionization degree, [alpha].

A conjugated amphiphilic polyelectrolyte, a poly(phenylene ethylene) (PPE), and the structurally analogous neutral polymer are synthesized. It is concluded on the basis of a combination of absorption and photoluminescence spectroscopy and dynamic light scattering that the solution-phase aggregation of the uncharged PPE could be reversibly controlled by varying the solvent polarity and concentration.

In the continuing challenge to find new routes to improve the performance of commercial lithium ion batteries cycling in alkyl carbonate-based electrolyte solutions, original designs, and new electrode materials are under active worldwide investigation. Our group has focused on the electrochemical behavior of a new generation of nanocomposite electrodes showing improved capacities (up to 3 times the capacity of conventional electrode materials). However, moving down to 'nanometric-scale' active materials leads to a significant increase in electrolyte degradation, compared to that taking place within commercial batteries. Postmortem electrolyte studies on experimental coin cells were conducted to understand the degradation mechanisms. Structural analysis of the organic degradation products were investigated using a combination of complementary high-resolution mass spectrometry techniques: desorption under electron impact, electrospray ionization, and gas chromatography coupled to a mass spectrometer equipped with electron impact and chemical ionization ion sources. Numerous organic degradation products such as ethylene oxide oligomers (with methyl, hydroxyl, phosphate, and methyl carbonate endings) have been characterized. In light of our findings, possible chemical or electrochemical pathways are proposed to account for their formation. A thorough knowledge of these degradation mechanisms will enable us to propose new electrolyte formulations to optimize nanocomposite-based lithium ion battery performance.

Ab initio quantum mechanics (QM) and classical molecular dynamics (MD) simulations are employed to model an electrolyte composed of a polyphosphazene (PP), lithium triflate (LiCF3SO3) and water. Structures and energetics are systematically studied by QM for binary complexes of Li(super +), CF3SO3(super -), and Li(super +)CF3SO3(super -) with water or PP fragments, and for ternary combinations of Li(super +)CF3SO3(super -), PP fragments and water.

Electrolyte properties of a novel lithium salt of a weakly coordinating anion, lithium tetra aluminate, are studied. It is used to design polymer electrolytes with high ionic conductivity.

Several studies are conducted to explain the formation and properties of the bifunctional layer-by-layer (LbL) construct made by the combination of permanent microbicidal polyelectrolyte multilayered (PEM) base film with a hydrolytically degradable PEM top film. These films are shown to be extremely efficient and hence can be used as coatings for different implantable devices.

The integration of layer-by-layer polyelectrolyte assemblies into single conical nanopores is described for analyzing the functional features arising from the creation of charged supramolecular assemblies within the constrained geometry of the nanofluidic device. The results have shown that the charge transport properties of single conical nanopores functionalized with poly(allylamine hydrochloride) (PAH)/poly(styrenesulfonate) (PSS) layers assembled into the nanopore.

The photophysics and electroluminescence (EL) of thin films of unthreaded and cyclodextrin-encapsulated poly(4,4' -diphenylenevinylene) (PDV) with potassium countercations, blended with poly(ethylene oxide) (PEO) are examined as a function of the PEO concentration. A blueshift of the EL spectrum during the devices turn-on is described and studied in terms of interference and doping effects.

A bioinformatics study is conducted to analyze the polyelectrolyte domains, as well as the intrinsic disorder observed within the intrinsically disordered proteins (IDP) family, Asprich. The functions of the domains of these proteins are shown to be highly controlled by the structural and surface charge density features.

Stable, homogeneous ultrathin films of uniformly dimensioned dual-pore carbon capsules with mesoporous walls and macroscopic empty cores are prepared by using layer-by-layer methods based on electrostatic interaction between a polyelectrolyte and a surfactant coating of the carbon capsules. The resulting dual-porous carbon capsule films are examined as a sensor substrate for vapors of different organic solvents.

Individual shells of the diatom Coscinodiscus are self-assembled into a rectangular array on a glass surface that has possessed a polyelectrolyte multilayer patterned through inkjet printing. The fine features of the diatom frustules are preserved as a result of the mild conditions of the deposition process and this method has enabled large-scale device applications that harness the unique properties of functionalized diatom biosilica.

A combination of atomic force microscopy (AFM) and Kelvin probe force microscopy (KFM) technique is used to study the formation of patterned self-assembled polyelectrolyte multilayer nanodots. The results indicated that the scanning probe microscopy (SPM) lithography is an excellent technique to pattern polyelectrolyte multilayer nanodots in which size is controllable with accuracy in nanoscale.

The studies have shown that a moderate change in the concentration of poly(sodium 4-styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) has a dramatic effect on the formation of defects in polyelectrolyte multilayers (PEMs). The combination of gas permeation selectivity and solution viscosity measurements has provided a powerful approach for gaining insight into defects in PEMs and the role that polyelectrolyte conformation has played in their formation.

Studies on the polymer electrolytes obtained by the casting technique from a solution containing chitosan, hydrochloric acid, and plasticizer such as glycerol, ethylene glycol, and sorbitol are reported. The results show that chitosan dissolved in HCl in different concentrations and plasticized with glycerol, ethylene glycol, and sorbitol, resulting in ion conductive samples.

Detail studies were conducted to explore the miscibility behavior and mechanisms of interaction for polymer blends of octa(phenol)octasilsequioxane (OP-POSS) and poly(methyl mechacrylate-co-poly(vinyl pyrrolidone) (PMMA-co-PVP). The results obtained provide insight into the stronger intermolecular hydrogen bonding compared to intramolecular hydrogen bonding after copolymerization with VP content due to the preference of OH groups to interact with the VP segments and the critical role of OP-POSS to enhance the ionic conductivity of the polymer electrolyte.

Ionic correlations in a polymer electrolyte stemming from ionic associations are analyzed by constructing elementary correlation functions. The extended Stolwijk and Obeidi (SO) model is used for estimating the dynamics of the free and non-free ions as well as their fractions from the single particle diffusivities and the collective diffusivity of the ions.

A study was conducted to examine four conjugated polyelectrolytes (CPEs) with identical backbone but with different pendant charges and charge compensating ions for the case of the cationic structures. The results showed that substantially different properties in the polymer structure could be achieved by variations of functional groups that are removed from the semiconducting, electronically delocalized framework.

The studies on the molecular mechanism observed in double-network (DN) hydrogels obtained from poly(2-acrlamido-2-methyl-1-propanesulfonic acid) (PAMPS) polyelectrolyte network and poly(acrylamide) (PAAm) linear polymer are reported. The mechanism provides insight into the periodic compositional fluctuations in the micrometer range induced by large strain deformation.

The relationship between the aggregation state and dynamic properties of block ionomer complexes (BICs) are examined based on amphiphilic ionic block copolymers. The coupling reactions involving polyion shell micelles are slower when compared to the coupling of linear polyions, which are attributed to the aggregation state of polyion shell micelles.

Several simulations are conducted to explain the overcharging charge inversion and reentrant condensation of the highly charged polyelectrolytes in tetravalent salt solutions. The charge inversion is shown to take place due to the presence of small ion size.

The diffusion of poly(diallyldimethylammonium chloride) (PDADMAC) polycations in coacervates formed from PDADMAC and the protein bovine serum albumin (BSA) is studied. Several ensembles of PDADMAC polycations with different diffusivities are observed.

The growth of multilayer formed by poly(sodium 4-styrene sulfonate) (PSSS) and poly(diallyldimethylammonium chloride) (PDDA) at different salt concentrations are examined by using quartz crystal microbalance with dissipation (QCM-D). The studies have shown that the multilayer growth is dominated by chain conformation and interpenetration of polyelectrolyte.

Postassembly reversible loading and unloading of nanoparticles (NPs) is shown in a swollen polyelectrolyte film. The variations of the structure of the layer-by-layer (LBL) layers and the NPs can be used for controlling the incorporation and release of the NPs.

A quartz crystal microbalance with dissipation (QCM-D) is used to study the effects of temperature, pH, and salt concentration on the layer-by-layer (LBL) deposition of sodium poly(styrene sulfonate) (PSS)/poly[2-(dimethylamino)ethyl methacrylate] (PDEM). The experimental results suggest that the LBL deposition of polyelectrolytes is influenced by the chain interpenetration and high temperature or high salt concentration can force the polyelectrolyte complexes to redissolve from the surface into the solution.

The optical, electrochemical, and electrochromic properties of several metallosupramolecular coordination polyelectrolytes (MEPEs) self assembled from rigid, [pi]-conjugated, pyridine ring functionalized bisterpyridines and metal ions is described. The findings from structure-property relationships of MEPEs could be applied to design new bisterpyridine-based metallosupramolecular functional materials.

The synthesis and characterization of graft and diblock ionic copolymers containing both fluorous and sulfonated polystyrene segments are described. The nanoarchitectured morphology has played a major role in determining the properties of proton conducting membranes.

A method is described for preparing highly conductive and stable organic-inorganic nanocomposite polyelectrolyte membranes with controlled spacing between inorganic segment and covalently bound sulfonic acid functional groups. The organic-inorganic nanocomposite is identified as a remarkable family of polyelectrolytes, which has provided new technological applications in high-temperature electrochemical devices including ion separations and electro-chemical sensors.

Small angle neutron scattering (SANS) method is used for examining the characteristics of highly extended conformations of polyelectrolytes incorporated into hybrid threadlike micelles at a stationary state and the conformation of the polyelectrolyte in the hybrid threadlike micelle highly oriented to the flow direction in a liquid crystal state induced by strong shear flows. The results have shown that the polyelectrolytes incorporated into the highly orientated micelle have the same conformation as those in the randomly orientated micelles in a quiescent state even at high shear rates.