Water-soluble fluorescent nanoparticles without distinct aggregation of conjugated polymer chains

In a previous study, we reported water-soluble light-emitting nanoparticles with distinct interchain aggregation states of the constituent conjugated polymers. These interchain states usually result in strong self-quenching, dramatically reducing the quantum efficiency of fluorescence. In the work reported in the present study, we developed new water-soluble fluorescent nanoparticles without distinct aggregation of the conjugated polymer chains, which demonstrated distinctive morphologies and optical properties. 'Strawberry' morphologies of the nanoparticles were directly observed using transmission electron microscopy. The conjugated polymers were dispersed in the individual cores of the nanoparticles and the majority of the core diameters were in the range 8-12 nm. The primary optical properties of the conjugated polymers in tetrahydrofuran still remained in the nanoparticles. The results suggest that the conjugated polymer chains formed a possible unimolecular structure without distinct aggregation in the nanoparticles.