A general approach is proposed to synthesize Janus polymer/inorganic composite nanosheets. Onto the amine-groupterminated side of the Janus inorganic nanosheets, initiators are covalently bonded. By a favorable grafting from initiator-terminated side, responsive polymers, for example PDEAEMA and PNIPAM, are synthesized by controlled polymerization for example ATRP or RAFT polymerization. Stable emulsions are easily formed in the presence of the Janus nanosheets, which can be easily de-emulsified by subtle changing physicochemical parameters, for example temperature and pH.

Janus nanosheets of polymer–inorganic layered composites are fabricated by crushing the corresponding Janus composite hollow spheres, which are synthesized by materialization of an amphiphilic emulsion interface with self-organized sol–gel process and subsequent polymer grafting onto the lipophilic side. The Janus composite nanosheets serve as solid surfactants to stabilize emulsion droplets, which are tolerant against solvents. Janus balance of the composite nanosheets is tunable crossing from more lipophilic to hydrophilic by alteration of polymer content. Thereafter, continuous phase of the emulsions can be inverted.