Janus composite nanosheets of PNIPAM/silica/PDEAEMA are synthesized by sequential ATRP grafting two polymers from the corresponding sides of the Janus silica nanosheets. They are dually responsive to pH and temperature since wettability of the two sides is tunable accordingly. The nanosheets can serve as a responsive solid emulsifier. Type and stability of the emulsions are triggered by simply changing pH and temperature.