Postdoctoral Research Fellow in Nanocrystal group (2009 - 2011)
University of Melbourne
Supervisor: Paul Mulvaney
Contact Details
Nanoscience Laboratory
Bio21 Institute & School of Chemistry
Bio21 Institute
Level 2 North
30 Flemington Rd
3010 Victoria
Australia
mkarg@unimelb.edu.au
Phone: +61 38344 2428
Fax: +61 39348 1595
Higher Education
2009 PhD
Thesis Title: Multi-responsive hybrid colloids based on microgels and nanoparticles
Technical University Berlin, Germany
Supervisors: Prof. T. Hellweg and Prof. R. von Klitzing
2006 Diploma in chemistry
Thesis Title: Neue intelligente Mikrogele
Technical University Berlin, Germany
Supervisor: Prof. T. Hellweg
Current Research Interests
- Synthesis and characterisation of hybrids in the meso- and nano-scale
- Organic/inorganic hybrids with magnetic, optical and/or catalytic properties
- Hybrids for SERS detection
- 2D- and 3D-arrangement of core-shell hybrid particles
Project Description
Hybrid materials combining organic and inorganic components are of recent interest, due to their unique properties. In the last years a major interest arose on composites of responsive polymers and metal nanoparticles such as gold spheres and rods. Such systems are interesting for many different applications comprising sensor design and drug delivery.
Despite synthetic aspects and fundamental investigations, my research is focussed on the construction of colloidal crystals and sensors for SERS detection. Different hybrid morphologies and compositions will be needed to fulfill these requirements. Well-known structures for organic/inorganic composites are core-shell particles, polymer networks filled with inorganic nanoparticles and polymer networks surrounded by inorganic nanoparticles.
Characterisation methods needed for the present project comprise different microscopies, spectroscopic investigations as well as scattering methods.
Polymer driven distance-control of nanoparticles
The plasmon coupling of individual noble-metal nanoparticles is of recent interest. In contrast to measurements of the ensemble average, single particle spectroscopy allows for the study of single coupling phenomena. Using dark-field microscopy, the plasmon coupling of different shaped gold nanoparticles (like nanorods and nanocubes) has been studied in different particle arrangements. However, the performed investigations do usually not allow for distance control between individual nanoparticles. Hence, I am interested in the fabrication of responsive polymer-linked nanoparticles. The responsive polymer, which links e.g. two gold nanorods can then be used to control the spacing between both plasmonic objects and plasmon coupling can be studied as a function of interparticle distance.
Selected Publications
M. Karg, S. Wellert, I. Pastoriza-Santos, A. Lapp, L. M. Liz-Marzán, T. Hellweg, "Poly(N-isopropylacrylamide) microgels with silica nanoparticle core: The volume phase transition/collapse of the polymer shell as seen by Small Angle Neutron Scattering and Dynamic Light Scattering", PCCP 2008, 10, 6708-6716
M. Karg, I. Pastoriza-Santos, B. Rodriguez-González, R. von Klitzing, S. Wellert, T. Hellweg, "Temperature, pH, and ionic strength induced changes of the swelling behavior of PNIPAM-Poly(Allylacetic-Acid) copolymer microgels", Langmuir 2008, 24, 6300-6306
R. Contreras-Cáceres, A. Sánchez-Iglesias, M. Karg, I. Pastoriza-Santos, J. Pérez-Juste, J. Pacifico, T. Hellweg, A. Fernández-Barbero, L. M. Liz-Marzán, "Encapsulation and Growth of Gold Nanoparticles in Thermoresponsive Microgels", Adv. Mat. 2008, 20, 1666-1670
M. Karg, I. Pastoriza-Santos, J. Pérez-Juste, T. Hellweg, L. M. Liz-Marzán, "Nanorod-coated PNIPAM microgels: Thermoresponsive optical properties", Small 2007, 3, 1222-1229
M. Karg, I. Pastoriza-Santos, L. M. Liz-Marzán, T. Hellweg, "A Versatile Approach for the Preparation of Thermosensitive PNIPAM Core-Shell Microgels with Nanoparticle Cores", ChemPhysChem 2006, 7, 2298-2301