Effect of polyethylenimine on the dispersion and electrophoretic deposition of nano-sized titania aqueous suspensions

Tang, Fang‐Fang; Uchikoshi, Tetsuo; Ozawa, Kiyoshi; Sakka, Yoshio

doi:10.1016/j.jeurceramsoc.2005.03.240

Cited by 128 publications

(48 citation statements)

References 19 publications

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“…This could be explained on the basis of the inability of the polyelectrolyte to neutralize and reverse the electrostatic charge of the nanoparticles on the substrate. The high zeta potential of the a-sol and low charge density of PEI (PEI is a weak polyelectrolyte and is partially protonated at pH < 10 [35] ) are responsible for this behavior. More details are presented in the Supporting Information ( Figure S2).…”

Section: Lbl Deposition On Cellulose Fibersmentioning

confidence: 99%

Nanoparticulate Hollow TiO₂ Fibers as Light Scatterers in Dye‐Sensitized Solar Cells: Layer‐by‐Layer Self‐Assembly Parameters and Mechanism

et al. 2011

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Hollow structures show both light scattering and light trapping, which makes them promising for dye-sensitized solar cell (DSSC) applications. In this work, nanoparticulate hollow TiO(2) fibers are prepared by layer-by-layer (LbL) self-assembly deposition of TiO(2) nanoparticles on natural cellulose fibers as template, followed by thermal removal of the template. The effect of LbL parameters such as the type and molecular weight of polyelectrolyte, number of dip cycles, and the TiO(2) dispersion (amorphous or crystalline sol) are investigated. LbL deposition with weak polyelectrolytes (polyethylenimine, PEI) gives greater nanoparticle deposition yield compared to strong polyelectrolytes (poly(diallyldimethylammonium chloride), PDDA). Decreasing the molecular weight of the polyelectrolyte results in more deposition of nanoparticles in each dip cycle with narrower pore size distribution. Fibers prepared by the deposition of crystalline TiO(2) nanoparticles show higher surface area and higher pore volume than amorphous nanoparticles. Scattering coefficients and backscattering properties of fibers are investigated and compared with those of commercial P25 nanoparticles. Composite P25-fiber films are electrophoretically deposited and employed as the photoanode in DSSC. Photoelectrochemical measurements showed an increase of around 50% in conversion efficiency. By employing the intensity-modulated photovoltage and photocurrent spectroscopy methods, it is shown that the performance improvement due to addition of fibers is mostly due to the increase in light-harvesting efficiency. The high surface area due to the nanoparticulate structure and strong light harvesting due to the hollow structure make these fibers promising scatterers in DSSCs.

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Section: Lbl Deposition On Cellulose Fibersmentioning

confidence: 99%

Nanoparticulate Hollow TiO₂ Fibers as Light Scatterers in Dye‐Sensitized Solar Cells: Layer‐by‐Layer Self‐Assembly Parameters and Mechanism

et al. 2011

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“…As summarized in Table 1, several papers have been published on this topic providing a variety of results [1,[6][7][8][9][10][11][12][13][14][15]. For example, Tang et al [6,7] stated that the pH value, ionic conductivity and viscosity are key factors of the EPD process.…”

Section: Introductionmentioning

confidence: 99%

“…And the addition of surfactant and sintering under higher temperature were necessary. Tang et al [8] investigated the mechanism of EPD behavior of an aqueous suspension with a dispersant of polyethylenimine (PEI) to modify the surface charge of the TiO 2 powders. The result reflected the synergetic effect of the viscosity and conductivity of the suspension as well as the surface electric charge of the particles in determining the deposition behavior of the particles.…”

Section: Introductionmentioning

confidence: 99%

Uniform design for the optimization of Al2O3 nanofilms produced by electrophoretic deposition

Song

Quan

et al. 2016

Surface and Coatings Technology

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Surface modification by means of nanostructures is of interest to enhance boiling heat transfer in various applications including the organic Rankine cycle (ORC). With the goal of obtaining rough and dense aluminum oxide (Al 2 O 3 ) nanofilms, the optimal combination of process parameters for electrophoretic deposition (EPD) based on the uniform design (UD) method is explored in this paper. The detailed procedures for the EPD process and UD method are presented. Four main influencing conditions controlling the EPD process were identified as: nanofluid concentration, deposition time, applied voltage and suspension pH. A series of tests were carried out based on the UD experimental design. A regression model and statistical analysis were applied to the results. Sensitivity analyses of the effect of the four main parameters on the roughness and deposited mass of Al 2 O 3 films were also carried out.The results showed that Al 2 O 3 nanofilms were deposited compactly and uniformly on the substrate. Within the range of the experiments, the preferred combination of process -4 g/cm 2 , respectively. A verification experiment was carried out at these conditions and gave values of roughness and deposited mass within 8% error of the expected ones as determined from the UD approach. It is concluded that uniform design is useful for the optimization of electrophoretic deposition requiring only 7 tests compared to 49 using the orthogonal design method.

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“…From the viewpoint of practical applications, colloidal processing is a suitable forming method for the manufacture of large volume of the g-Y 2 Si 2 O 7 component with a controllable microstructure. 18 To obtain a stable aqueous g-Y 2 Si 2 O 7 suspension, two commercial dispersants, polyethylenimine (PEI) and polyacrylic acid (PAA), which have been widely used in ceramic suspensions, [19][20][21][22][23][24][25] were used in the present work. PEI is a polybase containing primary, secondary, and tertiary amine groups in the ratio of 1:2:1.…”

mentioning

confidence: 99%

“…The three-dimensional branched molecule forms a spherical branched symmetric compact in solution. 19,[23][24][25] When PEI is dissolved in water, the lone pairs on its nitrogen atoms can attract protons in the solvent. At a pH of 10, PEI is considered to be an uncharged polymer and the degree of protonation is 0.01.…”

mentioning

confidence: 99%

Hydrolysis and Dispersion Properties of Aqueous Y₂Si₂O₇ Suspensions

Sun

Zhu

et al. 2009

Journal of the American Ceramic Society

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The dispersion of aqueous c-Y 2 Si 2 O 7 suspensions, which contain only one component but have a complex ion environment, was studied by the introduction of two different polymer dispersants, polyethylenimine (PEI) and polyacrylic acid (PAA). The suspension without any dispersant remains stable in the pH range of 9-11.5 because of electrostatic repulsion, while it is flocculated upon stirring due to the readsorption of hydrolyzed ions on the colloid surface. However, suspensions with 1 dwb% PEI exhibit greater stability in the pH range of 4-11.5. The addition of PEI shifts the isoelectric point (IEP) of the suspensions from pH 5.8 to 10.8. Near the IEP (pH IEP 5 10.8), the stability of the suspensions with PEI is dominated by the steric effect. When the pH is decreased to acid direction, the stabilization mechanism is changed from steric hindrance to an electrosteric effect little by little. PAA also has the effect of reducing the hydrolysis speed via a ''buffer effect'' in the basic pH range, but the lack of adsorption between the highly ionized anionic polymer molecules and the negative colloid particle surfaces shows no positive effect on hydrolysis of colloids and on the stabilization of Y 2 Si 2 O 7 suspensions.

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Effect of polyethylenimine on the dispersion and electrophoretic deposition of nano-sized titania aqueous suspensions

Cited by 128 publications

References 19 publications

Nanoparticulate Hollow TiO₂ Fibers as Light Scatterers in Dye‐Sensitized Solar Cells: Layer‐by‐Layer Self‐Assembly Parameters and Mechanism

Nanoparticulate Hollow TiO₂ Fibers as Light Scatterers in Dye‐Sensitized Solar Cells: Layer‐by‐Layer Self‐Assembly Parameters and Mechanism

Uniform design for the optimization of Al2O3 nanofilms produced by electrophoretic deposition

Hydrolysis and Dispersion Properties of Aqueous Y₂Si₂O₇ Suspensions

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Effect of polyethylenimine on the dispersion and electrophoretic deposition of nano-sized titania aqueous suspensions

Cited by 128 publications

References 19 publications

Nanoparticulate Hollow TiO2 Fibers as Light Scatterers in Dye‐Sensitized Solar Cells: Layer‐by‐Layer Self‐Assembly Parameters and Mechanism

Nanoparticulate Hollow TiO2 Fibers as Light Scatterers in Dye‐Sensitized Solar Cells: Layer‐by‐Layer Self‐Assembly Parameters and Mechanism

Uniform design for the optimization of Al2O3 nanofilms produced by electrophoretic deposition

Hydrolysis and Dispersion Properties of Aqueous Y2Si2O7 Suspensions

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Nanoparticulate Hollow TiO₂ Fibers as Light Scatterers in Dye‐Sensitized Solar Cells: Layer‐by‐Layer Self‐Assembly Parameters and Mechanism

Nanoparticulate Hollow TiO₂ Fibers as Light Scatterers in Dye‐Sensitized Solar Cells: Layer‐by‐Layer Self‐Assembly Parameters and Mechanism

Hydrolysis and Dispersion Properties of Aqueous Y₂Si₂O₇ Suspensions