title: Nanoparticle assembly of a photo- and pH-responsive random azobenzene copolymer.
abstract: Stimuli-responsive polymeric nanoparticles with a core of hydrophobic azobenzene-containing acrylate units and a shell of hydrophilic acrylic acid units were prepared from a novel photo- and pH-responsive amphiphilic random azobenzene copolymer. Upon UV light irradiation, the trans azobenzene changed to the cis form and thus the water contact angle and the absorption of water on the polymer film could be changed, while little effect was exerted on the morphology of the nanoparticles although the polarity of the core of nanoparticles increased. Adjusting pH of the nanoparticle solution could exert a strong effect on the morphology of the nanoparticles. The prime nanoparticles (pH 6) changed to nanoparticle aggregates at pH 3, and to swollen nanoparticles at pH 11. The controlled release of Nile Red from the nanoparticles under the stimuli was demonstrated.
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Feng
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Han
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Dong
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Yudong
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China. Electronic address: guojie.wang@mater.ustb.edu.cn.
authors.forename: Guojie
authors.initials: G
authors.lastname: Wang
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D011108:Polymers / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D014466:Ultraviolet Rays
chemical_list: D001391:Azo Compounds; D011108:Polymers; C009850:azobenzene
keywords: Azobenzene; Nanoparticles; Self-assembly; Stimuli-responsive