Experimental investigation of the rheological behavior and micro-morphology of the wormlike micelle cross-linked with polyelectrolyte-grafted nano silica and the associative polymer

This paper has investigated the rheological behavior and micro-morphology of CTAC wormlike micelle (WLM) which cross-linked with polyelectrolyte-grafted nanosilica (PEN) and nonionic hydrophobically-associating polymer (HAP). Cryo-transmission electron microscopy (Cryo-TEM) is adopted to observe the micro-morphology of the associative structure. Results show that PEN cross-linked with CTAC wormlike micelle exhibits higher zero-shear viscosity than the non-modified nano silica, and this viscosity is continuously raised as the PEN concentration is increased. PEN-micelle complex has excellent anti-salt properties and its zero-shear viscosity is increasing in a KCl concentration range of 0-10%. The shear viscosity of wormlike micelle is enhanced by HAP and polymer molecules dominate the rheological characteristic of the mixed fluid. The shear viscosity of HAP-micelle fluid is further increased by PEN. However, the rheological characteristic of the micelle-HAP-PEN complex is identical to that of wormlike micelle. The elasticity of wormlike micelle is noticeably enhanced by cross-linking with PEN and HAP. They stimulate the formation of micelle to significantly increase the length and rigidity of wormlike micelle. Surfactant molecules spontaneously arrange on the surface of PEN and grow outwards, which associates with HAP to generate the tighter three-dimensional network structure. {Graphical abstract}