Polymer Bulletin

, Volume 67, Issue 8, pp 1443–1454

Polymer-assisted formation of hydrophobized, shape-anisotropic zinc oxide nanoparticles via an inverse emulsion technique

  • Christian Geidel
  • Kathy Schmidtke
  • Markus Klapper
  • Klaus Müllen
Original Paper

DOI: 10.1007/s00289-011-0460-9

Cite this article as:
Geidel, C., Schmidtke, K., Klapper, M. et al. Polym. Bull. (2011) 67: 1443. doi:10.1007/s00289-011-0460-9

Abstract

A one-step inverse emulsion process using amphiphilic surface-active copolymers for the synthesis of hydrophobized, shape-anisotropic inorganic nanoparticles is presented. While such structures are normally prepared sequentially by particle formation and hydrophobization, we have combined both reactions. This approach is demonstrated exemplarily with zinc oxide (ZnO) nanoparticles. A key issue is the design of amphiphilic copolymers that act as emulsifiers to enable an aggregate-free redispersion of the particles and to stabilize the inverse emulsion for the precipitation in the droplets. In a first approach, the stabilizing as well as the hydrophobizing property of the copolymers are combined with the ability to control the crystallization in one polymer (structure-directing emulsifier—SDE). In a second approach, a mixture of two polymers is applied: an amphiphilic copolymer for hydrophobizing/stabilizing the inorganic nanoparticles and a polar or double hydrophilic polymer that induces the anisotropic growth of the ZnO nanocrystals (structure-directing agents—SDA). Homopolymers and block copolymers, consisting of phosphonic acid groups or propylene oxide groups, were used as SDAs. Typically, hydrophobized shape-anisotropic particles of up to 600 nm in length and with an aspect ratio of 1:4 were obtained.

Keywords

Zinc oxideAnisotropic shapeNanoparticleInverse emulsionIn situ hydrophobization

Supplementary material

289_2011_460_MOESM1_ESM.docx (52 kb)
Supplementary material 1 (DOCX 52 kb)

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Christian Geidel
    • 1
  • Kathy Schmidtke
    • 1
  • Markus Klapper
    • 1
  • Klaus Müllen
    • 1
  1. 1.Max Planck Institute for Polymer ResearchMainzGermany