AVS 56th International Symposium & Exhibition
    Applied Surface Science Wednesday Sessions
       Session AS+NS-WeM

Paper AS+NS-WeM12
Characterizing Environmentally Induced Changes in Nanoparticle Surface Chemistry

Wednesday, November 11, 2009, 11:40 am, Room C1

Session: Nanoparticle and Nanoscale Surface Chemistry II
Presenter: A. Pedersen, University of Wisconsin-Madison
Authors: A.N. Mangham, University of Wisconsin-Madison
P. Wiecinski, University of Wisconsin-Madison
S.P. Yang, University of Wisconsin-Madison
K.M. Louis, University of Wisconsin-Madison
R.E. Peterson, University of Wisconsin-Madison
W. Heideman, University of Wisconsin-Madison
A. Pedersen, University of Wisconsin-Madison
R.J. Hamers, University of Wisconsin-Madison
Correspondent: Click to Email
The routes of exposure and toxicity of nanoparticles in the environment are expected to be strongly affected by the nature of surface chemical groups exposed on the outside of the particles. We have developed a laboratory-based method that simulates oxidative processes in the environment, and have applied this method to investigate the resulting changes in surface chemistry of “bare” and ligand-functionalized nanoparticles. Using CdSe as a model system, we have compared the behavior of ligands bearing different surface anchor groups including carboxylic acid groups, amines, and phosphonates. Wrapping these ligand-modified nanoparticles with amphiphilic polymers can enhance the particle stability as well as the luminescence efficiency. Surprisingly, the type of surface anchoring group has a strong effect on the stability of even the polymer-wrapped nanoparticles. Using infrared, Raman, and x-ray photoelectron spectroscopies, combined with thermogravimetric analysis, we related the differences in stability of the nanoparticles to the chemical and physical structure of the ligands. Our results show that the most thermally stable groups do not necessarily provide the best protection against degradation. As time permits, the influence of the surface chemistry on the nanoparticle toxicity using a zebrafish model will be presented and discussed.