dear seyede 

Surfactants are widely used for dispersing graphene and functionalized graphene sheets (FGS) in colloidal suspensions, but there have been few studies of the structure of the dispersed graphene–surfactant complexes in suspension and of their time evolution. Here, we combine experimental study of efficiencies of ionic surfactants/polymers in suspending FGS in water with characterization using atomic force microscopy, small angle neutron scattering, and molecular simulations to probe the detailed structures of FGSs. The small angle scattering technique provides quantitative measurement of structure of graphene sheets in the solution. This study suggests that in both ionic and nonionic surfactants, the dispersion tends to degrade over time through detachment of the surfactant molecules and structural rearrangements. Ionic surfactants with strong interfacial binding and large molecular weight increase the dispersing power by over an order of magnitude.

for more details just follow the link below 

http://www.sciencedirect.com/science/article/pii/S2215038215300637

regards 

by following the leachability of GO via spectroscopy.

You can try casting the graphene oxide-polymer solution as film and studying fractured morphology. the one with better interaction will show better adhesion on surface of graphene-oxide.

What aim of your GO-polymer composite

Thank you all. I want to prepare a dispersion of GO-Polymer and it is important that their molecules have strong bond because GO will be moving under certain external forces and I want the polymer chains to (move with)  GO through its bond

dear seyede 

Surfactants are widely used for dispersing graphene and functionalized graphene sheets (FGS) in colloidal suspensions, but there have been few studies of the structure of the dispersed graphene–surfactant complexes in suspension and of their time evolution. Here, we combine experimental study of efficiencies of ionic surfactants/polymers in suspending FGS in water with characterization using atomic force microscopy, small angle neutron scattering, and molecular simulations to probe the detailed structures of FGSs. The small angle scattering technique provides quantitative measurement of structure of graphene sheets in the solution. This study suggests that in both ionic and nonionic surfactants, the dispersion tends to degrade over time through detachment of the surfactant molecules and structural rearrangements. Ionic surfactants with strong interfacial binding and large molecular weight increase the dispersing power by over an order of magnitude.

for more details just follow the link below 

http://www.sciencedirect.com/science/article/pii/S2215038215300637

regards 

Do a thorough centrifugation after the interaction; separate the GO. Then apply spectrophotometry to your supernatant and compare with the corresponding initial polymer solution.

Hi It seems polyethylene oxide is more suitable

Thank you so very much for your detailed answers . I appreciate your attention