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

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.

Effect of the colloidal zirconia on corrosion resistance of low-cemented alumina mixes against steel slag

“…It has been shown that by changing the Andersen coefficient, the size distribution of the porosities also changes [10]. On the other hand, in this work, if the porosities were perfectly aligned, the amount of penetration would probably be much greater.…”

“…Dolapix CE64 (an electrosteric dispersant, ammonium salt of a polycarboxylic acid) (Zschimmer and Schwarz), Dolapix CE64 (Zschimmer & Schwarz GmbH Co., Germany), were used in this study as a dispersing agent. It is an ammonium salt of a polycarboxylic acid, that acts through electrosteric stabilization [10]. Sodium tripolyphosphate (TPP) and citric acid were used as additives as well.…”

Effect of dispersion states (electrostatic/electrosteric stabilization) on particles arrangement in the yttria‐stabilized zirconia sediments

“…Low amounts of SV and high values of PD indicate a stable suspension. 29,30 N suspension has the highest SV (0.7 cm 3 /g) and the lowest PD (6.2%). In this suspension, particles have a high tendency to absorb each other and thereby create a flocculated and heterogeneous agglomerated sediment structure.…”

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“…Of the different water-soluble anionic polyelectrolyte dispersants available (e.g., PAA, PMAA), a new type of commercially available electrosteric dispersant agent, Dolapix CE64 (Zschimmer & Schwartz GmbH Co., Germany) was found to be the most suitable choice on basis of physical and chemical properties as well as practical experiments reported by different authors [3,[42][43][44][45][46][47][48][49][50][51][52]. According to the manufacturer information and result reported by different authors, Dolapix CE64 contains aqueous solution (~ 70 mass%) and ammonium salt (~ 30 mass%) of poly-(methacrylic acid) (PMAA-NH 4) , with a pH of 9 [3,[43][44][45][46][47][48][49][50][51][52].It has a molecular weight of 660 g/mol with a density (20°C) of approximately 1.2 g/cm 3 [3,[43][44][45][46][47][48][49][50][51][52]. It can easily dissociate in water and produces negatively charged polyions and ammonium counter-ions that create stability based on electrosteric interactions [3,[43][44][45][46][47][48][49]…”

“…According to the manufacturer information and result reported by different authors, Dolapix CE64 contains aqueous solution (~ 70 mass%) and ammonium salt (~ 30 mass%) of poly-(methacrylic acid) (PMAA-NH 4) , with a pH of 9 [3,[43][44][45][46][47][48][49][50][51][52].It has a molecular weight of 660 g/mol with a density (20°C) of approximately 1.2 g/cm 3 [3,[43][44][45][46][47][48][49][50][51][52]. It can easily dissociate in water and produces negatively charged polyions and ammonium counter-ions that create stability based on electrosteric interactions [3,[43][44][45][46][47][48][49][50][51][52]. Therefore, in this study Dolapix CE64 was used for highly concentrated suspensions stabilization.Dispersant concentration and solids concentration are both calculated in percentage by weight (abbreviated mass%) on dry powder basis.…”