Page 557 - Book Hosokawa Nanoparticle Technology Handbook

26 DISPERSION CONTROL OF Al O NANOPARTICLES IN ETHANOL APPLICATIONS
2 3
0.035
0.030 Mw 300
Repulsive force (N/m) 0.020 Mw 200
0.025

Mw 10000
0.015
Without dispersant
0.010
0.005
0.000
−0.005
0 5 10 15 20 25 30
Surface Distance (nm)
Figure 26.6
Figure 26.4 The repulsive force curve between the -Al O (7 nm)
3
2
The molecular size distribution of the branched PEIs in nanocolloidal probe and the substrate in ethanol with the
ethanol by dynamic light scattering method. branched PEIs and without a dispersant.

10.0
Molecular size (nm) 1.0

0.1
1 10 100 1000
Particle size (nm)

Figure 26.5 Figure 26.7
The relationship between the Al O nanoparticle size and The attractive force curve between the -Al O (7 nm)
2
3
2
3
the molecular size of PEIs for the suspensions below an nanocolloidal probe and the substrate in ethanol with the
apparent viscosity of 0.04 Pa s. branched PEI and without a dispersant.
Al O nanoparticles was investigated by using a from a long distance of 60 nm between the nanopar-
3
2
nanocolloidal probe AFM [6]. The repulsive and ticle and the substrate. The attractive force of the
attractive force curves between the Al O nanocolloid nanoparticle significantly depended on the MW of
2
3
probe and the Al O substrate in ethanol solutions the PEIs, compared to that of the sub-micron scaled
2
3
with the PEIs are shown in Figs. 26.6 and 26.7. The Al O particle.
3
2
repulsive force increased with an increase in MW of
the PEIs. The repulsive force of the PEI with MW of
10,000 displayed the extra large value ( 0.030 N/m). 4. Action mechanism of polymer dispersant on Al O
2 3
The adhesion strengths based on van der Waals nanoparticle suspension
attractive force in ethanol containing the PEI of MW
300 and without a dispersant were observed. The Based on the results, the action mechanism of the
adhesion strength of the PEI with MW of 1,200 did polymer dispersant on the dispersion and aggregation
not appear. Moreover, when the PEI with MW of behavior of the nanoparticle in ethanol suspension is
10,000 was used, the larger adhesion force which was shown in Fig. 26.8. The nanoparticles in ethanol
over twice of that without a dispersant, appeared suspension without a dispersant aggregate by
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