Robust Reactive Janus Composite Particles of Snowman Shape

We present a facile approach toward snowman-like silica@PDVB/PS Janus particles by seed emulsion polymerization using a gelable monomer MPS against a PDVB/PS hollow particle. Individual silica bulge is protruded from the seed particle surface, whose size is tunable. The silica@PDVB Janus particles are derived after dissolution of PS, which are robust to tolerate against organic solvents. Both sides are reactive for selective modifications to grow desired materials with tunable wettability and functionality. As solid emulsifiers, the Janus balance of the particles is tunable from more hydrophobic to more hydrophilic by changing either aspect size ratio or composition of the two sides.