Unimolecular micelles composed of inner coil-like blocks and outer rod-like blocks crafted by combination of living polymerization with click chemistry†

A new class of star-shaped coil–rod diblock copolymer polystyrene-block-poly(3-hexylthiophene) (PS-bP3HT) with well-defined structures and the ratio of coil to rod blocks were synthesized by a combination of atom transfer radical polymerization, the Grignard metathesis method, and click reaction. The star-shaped PS-b-P3HT diblock copolymers covalently connected to a b-cyclodextrin (b-CD) core were composed of 21-arm coil-like PS inner blocks and rod-like conjugated polymer P3HT outer blocks with narrowmolecular weight distribution. The intermediate and final products were systematically characterized and confirmed by gel permeation chromatography (GPC), H nuclear magnetic resonance (H-NMR), and Fourier transfer infrared (FTIR) spectroscopy. The optical properties of star-shaped PS-b-P3HT were examined by UV-Vis absorption and photoluminescence (PL) measurements. In comparison to the linear P3HT, due to their compact structure and the introduction of PS blocks, the optical properties of 21-arm, starshaped PS-b-P3HT were altered. The star-shaped PS-b-P3HT formed unimolecular micelles in good solvent as revealed by dynamic light scattering (DLS) and atomic force microscopy (AFM) studies.