Synthesis of aminoazobenzene-containing diblock copolymer and photoinduced deformation behavior of its micelle-like aggregates

A precursor polymer PEO-b-PEMA that contains anilino moieties is synthesized from EPAEMA by ATRP by using a PEOBr macroinitiator and CuBr/HMTETA catalyst system. The aminoazo-benzene-containing block copolymer PEO-b-PCN is obtained by the azo-coupling reaction between PEO-b-PEMA and the diazonium salt of 4-aminobenzonitrile. Results show that PEO-b-PCN has a narrow molecular weight distribution and the repeat unit numbers of the hydrophilic and hydrophobic blocks are 122 and 200, respectively. PEO-b-PCN can form uniform spherical aggregates by gradually adding water into its THF solution. Upon irradiation with a linearly polarized Ar+ laser beam, the spherical aggregates can be significantly elongated in the polarization direction of the light.