title: [Preparation method of polystyrene core-poly (acrylamide-acrylic acid) shell fluorescent microspheres].
abstract: To investigate the preparation method of polystyrene core-poly (acrylamide-acrylic acid) shell fluorescent microspheres.
  
  
  
  The polystyrene core-poly (acrylamide-acrylic acid) shell (P-(St-co-AAM)) fluorescent microspheres were prepared using fluorescent microspheres as the core and acrylamide/acrylic as polymerization monomer. Reaction conditions affecting the morphology of core-shell structure including feeding mode, initiator, cross linker, pH, concentration and swelling were studied.
  
  
  
  Fluorescent microscopy showed that the relatively uniform particle sizes were distributed in a range of 7-8 μm. Fourier transform infra-red spectroscopy (FT-IR) proved the existence of poly (acrylamide-acrylic acid) shell and amide group on the surface. The optimal conditions for seeding polymerization: azobisisobutyronitrile was used as the initiator in the absence of cross linker, after a 40 h swelling treatment by using alcohol with the appropriate reaction temperature (70 degree), reaction time (3 h) and pH(6-7). The average dispersion and stability were 25.14 % and 90.21%, respectively. The fluorescein release percentage was kept stable at approximately 30% after 40 h.
  
  
  
  The fluorescent microspheres prepared by this method have core-shell structure and satisfactory fluorescence properties with good dispersion and stability.
authors.affiliation: The First Affliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. yaowanxia@163.com
authors.forename: Wan-xia
authors.initials: WX
authors.lastname: Yao
authors.forename: Biao
authors.initials: B
authors.lastname: Yang
authors.forename: Qun
authors.initials: Q
authors.lastname: Li
authors.forename: Yao-jie
authors.initials: YJ
authors.lastname: Sun
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000180:Acrylic Resins / Q000737:chemistry*; D019793:Fluorescein / Q000737:chemistry*; D008863:Microspheres; D058105:Polymerization; D011137:Polystyrenes / Q000737:chemistry*; D000099166:Polyacrylamides
chemical_list: D000179:Acrylates; D000180:Acrylic Resins; D019793:Fluorescein; D011137:Polystyrenes; D000099166:Polyacrylamides; C036658:acrylic acid