EMAIL THIS PAGE TO A FRIEND

Langmuir : the ACS journal of surfaces and colloids

Use of Close-Packed Vesicular Dispersions to Stabilize Colloidal Particle Dispersions against Sedimentation.


PMID 26203879

Abstract

For many applications of colloidal dispersions, the particles must be suspended for a long time. This is often accomplished by preventing agglomeration, which generates aggregates of increasing size. Nevertheless, many colloidal dispersions of dense particles may settle even without agglomeration. Preventing sedimentation without significantly increasing the bulk dispersion viscosity is difficult and has received little attention in the literature. However, settling can be drastically reduced through the novel use of close-packed vesicular dispersions at high enough concentrations, which are non-Newtonian shear-thinning fluids. Such dispersions have much higher viscosities at the low shear stresses "felt" by sedimenting colloidal particles than at the high shear stresses relevant to bulk dispersion flow. In a practical example, dense TiO2 nanoparticles which normally would settle rapidly can remain suspended for at least 6 months without any observable sedimentation when they are introduced into a close-packed vesicular dispersion, while the dispersion retains its flowability. Cryo-TEM images reveal that the vesicles in these dispersions are tightly close-packed. Dynamic light scattering and electrophoretic mobility data also confirm that the vesicles in such dispersions have very low mobilities.

Related Materials

Product #

Image

Description

Molecular Formula

Add to Cart

382310
Didecyldimethylammonium bromide, 98%
C22H48BrN
359025
Didodecyldimethylammonium bromide, 98%
C26H56BrN