Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effect of silica colloids on the rheology of viscoelastic gels formed by
  the surfactant cetyl trimethylammonium tosylate   The effects of the addition of sub-micrometer sized colloidal silica spheres
on the linear and nonlinear rheology of semi-dilute solutions of a viscoelastic
gel are studied. For a 1.4 wt.% solution of the surfactant CTAT, a peak in the
zero shear rate viscosity $\eta_{\circ}$ is observed at approximately equal
weight percents of silica and CTAT. This peak shifts to lower silica
concentrations on increasing either the CTAT concentration or the surface
charge on silica and disappears when the CTAT concentration is increased to
2.6wt%. The increases in $\eta_{\circ}$ and the high frequency plateau modulus
G$_{\circ}$ on the introduction of SiO$_{2}$ are explained by considering the
increasingly entangled wormlike micelles that are formed due to the enhanced
screening of the electrostatic interactions. The observed decrease in the
values of G$_{\circ}$ and $\eta_{\circ}$ at higher concentrations of silica
particles is explained in terms of the formation of surfactant bilayers due to
the adsorption of the positively charged cetyl trimethylammonium to the
negatively charged silica.

12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg