Since last five years I have been focusing on synthesis of novel polyelectrolytes and developing processing methodologies to utilize thin layer of polymer films as functional materials. In these projects, oppositely charged polyelectrolytes were used as synthetic analogs to investigate the possible bioprocessing intermediates in the formation of bio-inspired materials. A general concept “controlled aggregation” has been exploited to form soluble complex coacervates. Then, various types of polyelectrolytes have been employed to produce layer-by-layer structures that retain liquid characteristics at the interfaces which are capable of spreading over any type of solid substrates even over non-fouling surfaces. With this methodology, modification of either hydrophobic or hydrophilic surfaces was facilitated. In these projects, scattering technologies and ellipsometric imaging have been used for characterization of surface properties of materials. I believe these results open new avenues, not only to understand the formation of self-assembled structures, but also facilitate to manufacture high-performance composites using aqueous-based chemistry and processing.
1- Layer-by-layer polyelectrolyte deposition: A mechanism for forming biocomposite materials
Yer Peng Tan, Umit Hakan Yildiz, Wei Wei, J. Herbert Waite and Ali Miserez 2013, Biomacromolecules, accepted (DOI: 10.1021/bm400448w).
2- Association of a Cylindrical Polyelectrolyte Brush with Tetravalent Counterions
Ruthard Christian, Maskos Michael, Umit Hakan Yildiz, et al. 2011, Macromolecular Rapid Communications, 32, 6, 523-527.
3- Fluorescent Nanoparticles through Self-Assembly of Linear Ionenes and Pyrenetetrasulfonate
Umit Hakan Yildiz, Koynov Kaloian, Groehn Franziska, 2009, Macromolecular Chemistry and Physics, 210, 20, 1678-1690.
4- Association of DNA with Multivalent Organic Counterions: From Flowers to Rods and Toroids
Li Yi, Umit Hakan Yildiz, Muellen Klaus, et al. 2009, Biomacromolecules, 10, 3, 530-540.