Syntheses of Amphiphilic Diblock Copolymers Containing a Conjugated Block and Their Self-Assembling Properties

An efficient approach to the syntheses of amphiphilic rod−coil diblock and coil−rod−coil triblock copolymers was developed. Each diblock copolymer consists of a perfectly monodispersed oligo(phenylene vinylene) covalently bonded to a poly(ethylene glycol) block with a very low polydispersity (<1.05). The structure and basic physical properties of these copolymers were characterized by various spectroscopic techniques such as NMR, MALDI-TOF, GPC, DSC, UV/vis, and the fluorescence study. These diblock copolymers were shown to possess remarkable self-assembling abilities, and long cylindrical micelles (>1 μm) were formed. TEM, SANS, and AFM studies showed that the core of the micelles has a diameter of ∼8−10 nm and was composed of an OPV block. TEM and SANS studies revealed that these OPV-PEG micelles have a cylindrical OPV core surrounded by a PEG corona. Cryo-TEM and SANS studies indicate that fibers were formed even in very dilute THF/H2O solutions. Since the conjugated OPV blocks exhibit liquid crystallinity and electric and optical properties, these micelles are interesting for studying the electroactive effect in a nanometer scale.