Effects of added silica nanoparticles on hectorite gels.

We present a study on the macroscopic, microscopic, and rheological behavior of mixtures of natural hectorite clay and different types of anionic Ludox silica spheres. Adding silica spheres to the weak hectorite gels leads the collapse of the suspensions, while the strong gels remain space-filling, though their storage modulus and the yield stress values diminish. We discuss what kind of structural rearrangements are possibly responsible for the macroscopic and rheological changes in the clay/silica mixtures.