Charging of  Poly(methyl methacrylate) (PMMA) Colloids in Cyclohexyl Bromide: Locking, Size Dependence, and Particle Mixtures

Linden, Marjolein N. van der; Stiefelhagen, Johan C. P.; Heessels-Gürboğa, Gülşen; Hoeven, Jessi E. S. van der; Elbers, Nina A.; Dijkstra, Marjolein; Blaaderen, Alfons van

doi:10.1021/la503665e

Cited by 28 publications

(58 citation statements)

References 57 publications

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“…The PMMA microparticles are sterically stabilized with covalently bound poly(12-hydroxystearic acid) [27]. Such particles have a surface charge that might be caused by adsorption of positively charged species resulting from the decomposition of CHB [23], chemical coupling of an amine catalyst during particle synthesis [28], or some combination of these mechanisms. In some of our experiments, we use spheres that are fluorescently labeled with absorbed rhodamine 6G dye [29].…”

Section: Colloidal Particlesmentioning

confidence: 99%

Charged hydrophobic colloids at an oil–aqueous phase interface

et al. 2015

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Hydrophobic poly(methyl methacrylate) (PMMA) colloidal particles, when dispersed in oil with a relatively high dielectric constant, can become highly charged. In the presence of an interface with a conducting aqueous phase, image-charge effects lead to strong binding of colloidal particles to the interface, even though the particles are wetted very little by the aqueous phase. We study both the behavior of individual colloidal particles as they approach the interface and the interactions between particles that are already interfacially bound. We demonstrate that using particles which are minimally wetted by the aqueous phase allows us to isolate and study those interactions which are due solely to charging of the particle surface in oil. Finally, we show that these interactions can be understood by a simple image-charge model in which the particle charge q is the sole fitting parameter.

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Section: Colloidal Particlesmentioning

confidence: 99%

Charged hydrophobic colloids at an oil–aqueous phase interface

et al. 2015

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“…11,12 In addition, the strong sectioning capabilities and increased resolution of confocal microscopy, allow for the investigation of the electrophoresis of concentrated dispersions on the single particle level. 3−5 Here we make use of the fact that with confocal microscopy it has recently been shown that both coordinates and orientations of rodlike silica model colloids can be obtained as well. 27 Here, we use silica rods with aspect ratios of 3.8 and 6.1 to measure the anisotropic electrophoretic motion as a function of κ a .…”

Section: Introductionmentioning

confidence: 99%

Microelectrophoresis of Silica Rods Using Confocal Microscopy

et al. 2017

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The electrophoretic mobility and the zeta potential (ζ) of fluorescently labeled colloidal silica rods, with an aspect ratio of 3.8 and 6.1, were determined with microelectrophoresis measurements using confocal microscopy. In the case where the colloidal particles all move at the same speed parallel to the direction of the electric field, we record a xyz-stack over the whole depth of the capillary. This method is faster and more robust compared to taking xyt-series at different depths inside the capillary to obtain the parabolic flow profile, as was done in previous work from our group. In some cases, rodlike particles do not move all at the same speed in the electric field, but exhibit a velocity that depends on the angle between the long axis of the rod and the electric field. We measured the orientation-dependent velocity of individual silica rods during electrophoresis as a function of κa, where κ–1 is the double layer thickness and a is the radius of the rod associated with the diameter. Thus, we determined the anisotropic electrophoretic mobility of the silica rods with different sized double layers. The size of the double layer was tuned by suspending silica rods in different solvents at different electrolyte concentrations. We compared these results with theoretical predictions. We show that even at already relatively high κa when the Smoluchowski limiting law is assumed to be valid (κa > 10), an orientation dependent velocity was measured. Furthermore, we observed that at decreasing values of κa the anisotropy in the electrophoretic mobility of the rods increases. However, in low polar solvents with κa < 1, this trend was reversed: the anisotropy in the electrophoretic mobility of the rods decreased. We argue that this decrease is due to end effects, which was already predicted theoretically. When end effects are not taken into account, this will lead to strong underestimation of the experimentally determined zeta potential.

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“…The effect of the chemical constituents can be seen by considering either the shell or core of the latexes. For example, differences in the precursor materials can have an effect on their properties: varying the purity of the HSA monomer or the specific details of the synthesis can change the degree of polymerization of the PHSA brushes [38,52] and using different amine catalysts can change the polarity of charged latexes [53]. Additionally, the solvent can influence the properties of the latexes.…”

Section: Introductionmentioning

confidence: 99%