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Direct Probing of Dispersion Quality of ZrO2 Nanoparticles Coated by Polyelectrolyte at Different Concentrated Suspensions.

Sarraf H, Qian Z, Škarpová L, Wang B, Herbig R, Maryška M, Bartovska L, Havrda J, Anvari B - Nanoscale Res Lett (2015)

Bottom Line: It is found that an optimum amount of 1.4 mass% dispersant at the inherent pH (>9.2) can be attached fully onto the nanoparticles with sufficient electrosteric dispersion effects, suitable for casting applications.Supplementary scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) analyses followed by colorization effect were taken to verify the visible interaction between dispersant and nanoparticles surfaces.This study will be of interest to materials scientists and engineers who are dealing with dispersion technology, nanoparticle surface treatments, functionalization, characterization, and application of bio/nanoparticle suspensions at various concentrations using different types of polymers.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, China. hsarraf@wgu.edu.

ABSTRACT
This study reports useful application of the electrokinetic sonic amplitude (ESA) technique in combination with rheometry and electron microscopy techniques for direct probing the stability of low and high-concentrated zirconia (ZrO2) nanosuspensions in the presence of an alkali-free anionic polyelectrolyte dispersant Dolapix CE64. A comparative study of the electrokinetic characteristics and the rheological behavior of concentrated ZrO2 nanosuspensions has been done. Good agreement was obtained from relationship between the electrokinetic characteristics (zeta potential, ESA signal), viscosity, and its pH dependence for each concentrated ZrO2 nanosuspension with different dispersant concentration in the range of 0.9-1.5 mass%. A nanoscale colloidal hypothesis is proposed to illustrate that the addition of different amounts of dispersant influences on both the stability and the electrokinetic and rheological properties of concentrated ZrO2 nanosuspensions. It is found that an optimum amount of 1.4 mass% dispersant at the inherent pH (>9.2) can be attached fully onto the nanoparticles with sufficient electrosteric dispersion effects, suitable for casting applications. Supplementary scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) analyses followed by colorization effect were taken to verify the visible interaction between dispersant and nanoparticles surfaces. SEM and HR-TEM images proved the existence of visible coverage of dispersant on the surface of individual nanoparticles and showed that thin polyelectrolyte layers were physically bound onto the particles' surfaces. This study will be of interest to materials scientists and engineers who are dealing with dispersion technology, nanoparticle surface treatments, functionalization, characterization, and application of bio/nanoparticle suspensions at various concentrations using different types of polymers.

No MeSH data available.


Related in: MedlinePlus

a, b Relationship between a ESA and pH magnitudes and b viscosity and pH magnitudes at the shear rate of 50 s−1 of high-concentrated ZrO2 nanosuspensions (with constant 77-mass% solids loading) as a function of dispersant concentration
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Fig8: a, b Relationship between a ESA and pH magnitudes and b viscosity and pH magnitudes at the shear rate of 50 s−1 of high-concentrated ZrO2 nanosuspensions (with constant 77-mass% solids loading) as a function of dispersant concentration

Mentions: A comparative investigation conducted to determine the relationship between ESA, pH, and suspension viscosity values (at the shear rate of 50 s−1) of concentrated 77 mass% ZrO2 nanosuspension as a function of dispersant concentration is shown in Fig. 8a, b. The comparison of the results obtained from Table 3, and Fig. 8a, b confirms that the amount of 1.4 mass% Dolapix CE64 is the optimum amount of anionic polyelectrolyte that can be adsorbed onto the surface of ZrO2 nanoparticles, leading to stabilize a concentrated ZrO2 nanosuspension at the inherent pH >9.2. This result is also confirmed by comparing the zeta-potential and suspension viscosity as a function of dispersant concentration in the range of 0.9–1.5 mass% on concentrated 77 mass% ZrO2 nanosuspensions, see Fig. 9. It is evident that viscosity (η) presents a minimum (~0.18 Pa.s) at shear rate of 50 s−1 and ζ-potential value maximum (−8 mV) at 1.4 mass% of dispersant corresponding to the optimum powder dispersion. In addition, the results from Figs. 8 and 9, and Table 3 indicate that at higher concentrations of dispersant (>1.4 mass%, above the optimum value), the viscosity increases slightly and the magnitude of ζ-potential value decreases, relatively. It can be concluded that the addition of optimum amount 1.4 mass% of Dolapix CE64 to a concentrated 77 mass% ZrO2 nanosuspension at pH 9.27 provided electrosteric dispersion. It is in good agreement with our proposed hypothesis and recently reported results from adsorption analysis [32, 47]. Further, as it can be seen in Fig. 9, we also consider that both the zeta-potential and viscosity are relatively constant between dispersant concentrations of 1.2 and 1.5 mass%, with an optimum value for both parameters occurring at a concentration of 1.4 mass%.Fig. 8


Direct Probing of Dispersion Quality of ZrO2 Nanoparticles Coated by Polyelectrolyte at Different Concentrated Suspensions.

Sarraf H, Qian Z, Škarpová L, Wang B, Herbig R, Maryška M, Bartovska L, Havrda J, Anvari B - Nanoscale Res Lett (2015)

a, b Relationship between a ESA and pH magnitudes and b viscosity and pH magnitudes at the shear rate of 50 s−1 of high-concentrated ZrO2 nanosuspensions (with constant 77-mass% solids loading) as a function of dispersant concentration
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4666182&req=5

Fig8: a, b Relationship between a ESA and pH magnitudes and b viscosity and pH magnitudes at the shear rate of 50 s−1 of high-concentrated ZrO2 nanosuspensions (with constant 77-mass% solids loading) as a function of dispersant concentration
Mentions: A comparative investigation conducted to determine the relationship between ESA, pH, and suspension viscosity values (at the shear rate of 50 s−1) of concentrated 77 mass% ZrO2 nanosuspension as a function of dispersant concentration is shown in Fig. 8a, b. The comparison of the results obtained from Table 3, and Fig. 8a, b confirms that the amount of 1.4 mass% Dolapix CE64 is the optimum amount of anionic polyelectrolyte that can be adsorbed onto the surface of ZrO2 nanoparticles, leading to stabilize a concentrated ZrO2 nanosuspension at the inherent pH >9.2. This result is also confirmed by comparing the zeta-potential and suspension viscosity as a function of dispersant concentration in the range of 0.9–1.5 mass% on concentrated 77 mass% ZrO2 nanosuspensions, see Fig. 9. It is evident that viscosity (η) presents a minimum (~0.18 Pa.s) at shear rate of 50 s−1 and ζ-potential value maximum (−8 mV) at 1.4 mass% of dispersant corresponding to the optimum powder dispersion. In addition, the results from Figs. 8 and 9, and Table 3 indicate that at higher concentrations of dispersant (>1.4 mass%, above the optimum value), the viscosity increases slightly and the magnitude of ζ-potential value decreases, relatively. It can be concluded that the addition of optimum amount 1.4 mass% of Dolapix CE64 to a concentrated 77 mass% ZrO2 nanosuspension at pH 9.27 provided electrosteric dispersion. It is in good agreement with our proposed hypothesis and recently reported results from adsorption analysis [32, 47]. Further, as it can be seen in Fig. 9, we also consider that both the zeta-potential and viscosity are relatively constant between dispersant concentrations of 1.2 and 1.5 mass%, with an optimum value for both parameters occurring at a concentration of 1.4 mass%.Fig. 8

Bottom Line: It is found that an optimum amount of 1.4 mass% dispersant at the inherent pH (>9.2) can be attached fully onto the nanoparticles with sufficient electrosteric dispersion effects, suitable for casting applications.Supplementary scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) analyses followed by colorization effect were taken to verify the visible interaction between dispersant and nanoparticles surfaces.This study will be of interest to materials scientists and engineers who are dealing with dispersion technology, nanoparticle surface treatments, functionalization, characterization, and application of bio/nanoparticle suspensions at various concentrations using different types of polymers.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, China. hsarraf@wgu.edu.

ABSTRACT
This study reports useful application of the electrokinetic sonic amplitude (ESA) technique in combination with rheometry and electron microscopy techniques for direct probing the stability of low and high-concentrated zirconia (ZrO2) nanosuspensions in the presence of an alkali-free anionic polyelectrolyte dispersant Dolapix CE64. A comparative study of the electrokinetic characteristics and the rheological behavior of concentrated ZrO2 nanosuspensions has been done. Good agreement was obtained from relationship between the electrokinetic characteristics (zeta potential, ESA signal), viscosity, and its pH dependence for each concentrated ZrO2 nanosuspension with different dispersant concentration in the range of 0.9-1.5 mass%. A nanoscale colloidal hypothesis is proposed to illustrate that the addition of different amounts of dispersant influences on both the stability and the electrokinetic and rheological properties of concentrated ZrO2 nanosuspensions. It is found that an optimum amount of 1.4 mass% dispersant at the inherent pH (>9.2) can be attached fully onto the nanoparticles with sufficient electrosteric dispersion effects, suitable for casting applications. Supplementary scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) analyses followed by colorization effect were taken to verify the visible interaction between dispersant and nanoparticles surfaces. SEM and HR-TEM images proved the existence of visible coverage of dispersant on the surface of individual nanoparticles and showed that thin polyelectrolyte layers were physically bound onto the particles' surfaces. This study will be of interest to materials scientists and engineers who are dealing with dispersion technology, nanoparticle surface treatments, functionalization, characterization, and application of bio/nanoparticle suspensions at various concentrations using different types of polymers.

No MeSH data available.


Related in: MedlinePlus