Janus nanoparticles with both faces selectively functionalized for click chemistryElectronic supplementary information (ESI) available: Schemes of the different reactions, amount of reagents and yield of the polymerization reactions, IR and NMR spectra of the copolymers and their compositions, formulations of the emulsions, diameters and surface density of functional groups for the nanoparticles, TEM micrographs of the Janus nanoparticles, and absorption and fluorescence spectra of the clickable

Janus nanoparticles presenting one face functionalized with azide and one face functionalized with alkyne groups were prepared in water. The surface density of the functional groups could be adjusted by controlling the functional group density in the polymers used to generate the Janus particles. The control was achieved by the preparation of copolymers in which the ratio of the functional monomer was varied by free-radical polymerization and by the use of atom transfer radical polymerization (ATRP) with functional initiators. Furthermore, reagents and methods were developed to quantify the alkyne and azide groups on the surface of the Janus particles. Thus, the activity of the groups was also proven. Janus nanoparticles presenting one face functionalized with azide and one face functionalized with alkyne groups were prepared in water.