Surface charge(zeta potential) of the GO nanosheets is an important property in this subject. Surface charge  of GO nanosheets is less in acidic media and more in basic mediums,i.e. the repulsion forces between GO nanosheets would be more in basic media .At high pH values ,and due to repulsion forces, stable dispersion of graphene oxide nanosheets is expected. Stability of GO nanosheets is important to the production of assembled GO or reduced GO for several applications electronic, optical, environmental and biological applications.