Metal nanocomposite particles

Microgel-“active carrier system”

Microgels can act much in a way of a “nanoreactor” that immobilizes the metallic nanoparticles. Metallic nanoparticles embedded in such a network are fully accessible by reactant at low temperature. Above the transition, however, the marked shrinking of the network should be followed by a concomitant slowing down of the diffusion of reactants within the network. Thus, the catalytic activity of embedded metal nanoparticles can be modulated by the volume transition of microgel particles.


References:

  1. Y. Lu, Y. Mei, M. Ballauff, M. Drechsler, Angew. Chem. Int. Ed. Engl. 2006, 45: 813-816.
  2. J. Crassous, Y. Drechsler, Y. Talmon, M. Ballauff, Langmuir 2006, 22, 2403.
  3. M. Ballauff, Y. Lu, Polymer (Feature Article) 2007, 48:1815-1823.
  4. Y. Mei, Y. Lu, F. Polzer, M. Ballauff, M. Drechsler, Chem. Mater. 2007, 19, 1062-1069.
  5. Y. Lu, S. Proch, M. Schrinner, M. Drechsler, R. Kempe, M. Ballauff, J. Mater. Chem. 2009, 19, 3955 – 3961.



Spherical polyelectrolyte brush particles

Spherical polyelectrolyte brushes (SPB) consist of a solid core (diameter: ca.100nm) onto which long chains of anionic or cationic polyelectrolyte are densely grafted. Metal ions can be immobilized into polyelectrolyte brushes as counter ions. Reduction of these immobilized metal ions leads to nanoparticles of the respective metal. These noble metal nanoparticles or nanoalloys can be used for catalysis in aqueous media, that is, under very mild conditions. Thus, the composite systems of metallic nanoparticles and spherical polyelectrolyte brushes allow us to do “green chemistry” and conduct chemical reaction in a very efficient way.


References:

  1. Y. Mei, G. Sharma, Y. Lu, M. Ballauff, M. Drechsler, T. Irrgang, R. Kempe, Langmuir 2005, 21: 12229.
  2. G. Sharma, Y. Mei, Y. Lu, M. Ballauff, T. Irrgang, R. Kempe, J. Catalysis, 2007, 246(1): 10-14.
  3. M. Schrinner, S. Proch, Y. Mei, R. Kempe, N. Miyajima, M. Ballauff, Adv. Mater. 2008, 20, 1928.
  4. M. Schrinner, M. Ballauff, Y. Talmon, Y. Kauffmann, J. Thun, M. Möller, J. Breu, Science 2009, 323, 617.
  5. Y. Lu, A. Wittemann, M. Ballauff, Macromol. Rapid Commun. 2009, 30, 806.