Preparation of Carbon Nanospheres from Diblock Copolymer Micelles with Cores Containing Curable Acetylenic Groups

We prepared carbon nanospheres by pyrolysis of core cross-linked diblock copolymer micelles. Poly(ethylene oxide)- b -poly(4-ethynylstyrene) (PEO−PES) with a hydrophobic block having curable acetylenic groups was synthesized by atom transfer radical polymerization. The number-average molecular weight ( M n ) of the PES block was calculated to be 2200 from the peak area ratio of the PEO block to the PES block and the M n of PEO (5000). A micelle with the size of about 28 nm was prepared by dissolving PEO−PES in water (0.05 mg/mL). A micelle core consisting of PES blocks was cross-linked by the photoreaction of acetylenic groups. In the subsequent pyrolysis, the cross-linked core was carbonized and the PEO block of the shell eliminated, resulting in a carbon nanosphere with a diameter of about 8 nm. The FT-IR spectrum showed that all of the characteristic bands for the diblock copolymers disappeared after pyrolysis. The Raman scattering spectrum of the carbon nanosphere exhibited typical partially graphitic carbon characteristics, with a strong and relatively narrow band at 1590 cm -1 and a broad band at 1350 cm -1, corresponding to graphitic species (G-band) and disordered species (D-band), respectively.