The nano-particle consists two principal constituent monomers, of which one is electrolyte with sulfonic acid group: 2-Acrylamido-2-methyl-1-propane sulfonic acid (AMPS), and the other is multi-vinyl: 1,1,1-Trimethylolpropane triacrylate (TMPTA). Synthesis was found to be composed of two stages. The early precipitation polymerization leads to the formation of nuclei, which grow gradually to particulate core of size about 10 to 20 nm at least. Subsequent emulsion-assisted polymerization permits the formation of electrolytic shell part over the core. The reaction control was facilitated through the photo-initiation mechanism at ambient temperature. The particle composition was revealed by FTIR, and the characterization of particle size was effectuated by both DLS and FESEM. IR spectrum as shown below confirms that TMTPA (n ̅ = 1732 cm-1, ester C=O) and AMPS (n ̅ = 1040 cm-1, symmetric stretching sulfonic SO3 hydrated) both constitute significantly the particle. The particle size was measured to be about 20~30 nm by FESEM as indicated in the micrograph below, whereas, about 60~70 nm by DLS. This large difference, between dry vacuum state and aqueous solution state, reveals the fact that the hydrodynamic volume of particle may represent the tremendous swelling of polyelectrolyte shell part in aqueous solution. The quantitative composition of particle will be pursued by elemental analysis, EDS, XPS. And the morphologic core-shell structure will be characterized by TEM and SAXS.
