In this paper

the effect of the micro-block length of the micro-block associating polymer and the concentration of the sodium dodecyl sulfate (SDS) on the rheological properties of the polymer / surfactant system was studied. The results show that micro-block length has the greater impact on the viscosity of hydrophobically associating polymer solution. The associating polymer with longer block has the larger tendency to form the intermolecular association and the higher viscosity. As the addition of SDS

the viscosity of the polymer/surfactant system reaches an extremum in short term

then loweres and keeps at a stable value. The longer the block is

the larger the extreme viscosity is. With the increasing micro-block length

the polymer/SDS system also exhibits the stronger shear thickening property and the largerviscoelastic behavior. Comparing the variation trend of the plateau modulus (

G

0

) of solution system with the one of terminal relaxation time (

T

R

)

we found that the micro-block length and the SDS concentration all have the greater impact on the physical crosslinking density of the the polymer/surfactant system and less impact on the physical crosslinking strength. These results provide an important insight into the underlying mechanism of the interactions between surfactants and the micro-block associating polymer.