A facile approach for preparing core-shell composite microspheres with tunable surface coverage was proposed.High performance liquid chromatography and zeta potential results showed that

rebalancing of emulsifiers' adsorption and desorption occurred when core and shell particles were mixed

and the cationic emulsifier desorbed from the core particle might neutralize the anionic emulsifier on the surface of shell particles.This resulted in a low gap of the zeta potential values between the core and the shell particles

and led to fail of the electrostatic-induced heterocoagulation.It was found that both the stability of the dispersion system and the contents of the free cationic emulsifier could be regulated by adding nonionic emulsifier.Subsequently

the heterocoagulation was successfully achieved as the contents of total emulsifier were kept at 1 wt%.Thus

by adjusting the ratio of nonionic and cationic emulsifier content

the surface coverage of composite microspheres could be easily controlled.The influence of pH value and electrolyte content on the surface coverage of core-shell composite microspheres was also discussed in this work.