Surfactant-free miniemulsion approach for low band gap rod-coil block copolymer water-processable nanoparticle fabrication: Film preparation and morphological characterization

The aqueous processing of hydrophobic conjugated polymers to produce nanoparticles is an emerging technology with wide application in photonic, optoelectronic, biological and medical areas. The insertion of 4VP-based tailored segment in the polymeric backbone prevents the surfactant addition during the aqueous nanoparticle fabrication. Four amphiphilic low band gap rod-coil block copolymers, constituted by a semiconducting rigid block and differing in the coil molecular structure and length, were processed in aqueous medium using the miniemulsion approach without surfactant use. Stable water-processable nanoparticles (WPNPs) suspended in aqueous medium were obtained, and WPNP-based films were deposited. The STEM-EDX analysis revealed the WPNP internal composition. The S-concentration, connected with the rod block location, is higher in the WPNP core, and the C-concentration higher on the WPNP edge when pure 4VP-based coils are present, confirming their surfactant-like role.