In-Situ Template Synthesis of a Polymer/Semiconductor Nanohybrid Using Amphiphilic Conducting Block Copolymers

In this study, we synthesized organic/inorganic hybrid materials containing cadmium sulfide (CdS) nanoparticles using a novel amphiphilic conducting block copolymer its a synergistic structure-directing template and in efficient exciton quencher of the hybrid. The amphiphilic rod-coil block copolymer of polyphenylene-b-poly(2-vinyl pyridine) (PPH-PVP) was first prepared from its coil-coil precursor block copolymer of poly(1,3-cyclohexadiene)-b-poly(2-vinyl pyridine) (PCHD-PVP) by using sequential anionic polymerization followed by the aromatization reaction of converting the PCHD block to form conducting PPH. The synthesized PCHD-PVP block copolymers self-assembled into different bulk nanostructures of lamellae, cylinders, and spheres at a Volume fraction similar to that of many coil-coil block copolymer systems. However, all enhanced chain-stiffness-induced morphological transformation was observed after the aromatization reaction. This is evidenced by the TEM observation in which both spherical and cylindrical structured PCHD-PVPs transform into lamellar Structured PPH-PVPs after aromatization. In addition to the bulk-phase transformation, the rigid-rod characteristic of the conducting PPH block also affects the self-assembling property of the block copolymers ill their Solution state. US nanoparticles were synthesized in situ in a selective solvent of THF using PCHD-PVP and PPH-PVP micelles as nanoreactors. The PPH-PVP/Cd ion in THF exhibits a new ringlike structure Of uniform size (similar to 50 nm) with PPH in the inner Hill and complexed PVP/Cd ions in the outer Hill as a result of the effects of strong intermolecular forces between PPH segments and the solvophobic interaction. US nanoclusters were subsequently synthesized in situ from the PPH-PVP/Cd2+ ring structure, forming a nanohybrid with intimate contact between the PPH domain and US nanoparticles. In particular, we found that there is all efficient energy/electron transfer between the conducting PPH domain and US nanoparticles in the hybrid, resulting ill an enhanced PL quenching effect. The novel nanohybrid shows the potential to be used for optoelectronic applications.