title: RETRACTED: Size-controlled spherical polymer nanoparticles: synthesis with tandem acoustic emulsification followed by soap-free emulsion polymerization and one-step fabrication of colloidal crystal films of various colors.
abstract: This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).
  
  This article was retracted at the request of the Editor. The above paper is essentially a duplicate of an original Article in “Size-Controlled Synthesis of Polymer Nanoparticles with Tandem Acoustic Emulsification Followed by Soap-Free Emulsion Polymerization” ACS Macro Lett., 2013, 2 (6), pp 482–484, 10.1021/mz4001817.
authors.affiliation: Department of Environment and System Sciences, Yokohama National University, Yokohama 240-8501, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hirai
authors.affiliation: Department of Environment and System Sciences, Yokohama National University, Yokohama 240-8501, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Nakabayashi
authors.affiliation: Department of Electronic Chemistry, Tokyo Institute of Technology, Yokohama 226-8502, Japan.
authors.forename: Maya
authors.initials: M
authors.lastname: Kojima
authors.affiliation: Department of Environment and System Sciences, Yokohama National University, Yokohama 240-8501, Japan; Department of Electronic Chemistry, Tokyo Institute of Technology, Yokohama 226-8502, Japan. Electronic address: atobe@ynu.ac.jp.
authors.forename: Mahito
authors.initials: M
authors.lastname: Atobe
keywords: Colloidal crystal film; Polymethylmethacrylate (PMMA); Size-controlled polymer particle; Structural color; Tandem acoustic emulsification