Hybrid Materials

Contact person: K. Lang, Laboratory of Bioinorganic Chemistry

We focus on the design of photofunctional materials whose function is initiated by light. These materials are composed of photosensitizers that are incorporated in inorganic materials (clay minerals, layered hydroxides, MOFs) and polymers (e.g., polymeric nanofibers). Photosensitizers (in our case mostly porphyrinic compounds and molybdenum-based functionalized clusters) are capable of transferring absorbed energy to atmospheric oxygen molecules to form singlet oxygen. Singlet oxygen is very reactive oxygen species. It degrades biomolecules and therefore singlet oxygen is harmful to bacteria. The properties of singlet oxygen can be useful for construction of materials, bulk or thin surfaces, having bactericidal properties activated by visible light. The advantage of photosensitizers is that these molecules are effective at very low concentrations because one molecule can be repeatedly excited to produce many molecules of singlet oxygen. We have proven that the surface of the materials with incorporated photosensitizers is bactericidal under visible light.

Layered hydroxides. The respective layers of layered hydroxides are composed of cations (e.g., Zn, Mg, Al, Ni) with coordinated OH groups. The positive charge of the layers is compensated by anionic species intercalated in the interlayer spacing. These anions impose functionality to the materials based on layered hydroxides.

Our results

• The usage of layered materials as nanocontainers and nanofillers for the development of photobactericidal surfaces based on porphyrin-layered material/polymer composites
• The fabrication of oriented hydroxide and oxide (e.g., ZnO) films
• Manipulation with the hydroxide nanolayers (thickness of 0.48 nm) and the preparation of ZnO nanoplatelets (see the image from electron microscope).
• Polymeric nanofibers with imbedded porphyrin molecules are fluorescent, exhibit delayed fluorescence and production of singlet oxygen upon irradiation with visible light. Singlet oxygen is a key factor inducing bactericidal and virocidal properties of the nanofiber surface (Micrograph from a microscope shows the textile structure, fluorescence properties and the formation of singlet oxygen are shown on the right side).

Selected Papers 

J. Demel, J. Pleštil, P. Bezdička, P. Janda, M. Klementová, K. Lang: Few-Layer ZnO Nanosheets: Preparation, Properties, and Films with Exposed Facets. J. Phys. Chem. C 115 (2011) 24702-24706.

M. Jiřičková, J. Demel, P. Kubát, J. Hostomský, F. Kovanda, K. Lang: Photoactive Self-Standing Films Made of Layered Double Hydroxides with Arranged Porphyrin Molecules. J. Phys. Chem. C 115(44) (2011) 21700–21706.

J. Demel, J. Pleštil, P. Bezdička, P. Janda, M. Klementová, K. Lang: Layered zinc hydroxide salts: Delamination, preferred orientation of hydroxide lamellae, and formation of ZnO nanodiscs. J. Colloid Inter. Sci. 360 (2011) 532-539.

J. Mosinger, K. Lang, J. Hostomský, J. Franc, J. Sýkora, M. Hof, P. Kubát: Singlet oxygen imaging in polymeric nanofibers by delayed fluorescence. J. Phys. Chem. B 114 (2010) 15773–15779.

J. Demel, P. Kubát, I. Jirka, P. Kovář, M. Pospíšil, K. Lang: Inorganic-organic hybrid materials: layered zinc hydroxide salts with intercalated porphyrin sensitizers. J. Phys. Chem. C 114 (2010) 16321-16328.

E. Káfuňková, K. Lang, P. Kubát, M. Klementová, J. Mosinger, M. Šlouf, A.-L. Troutier-Thuilliez, F. Leroux, V. Verney, C. Taviot-Guého: Porphyrin-LDH dispersed polymer composites as novel ecological photoactive surfaces. J. Mater. Chem. 20 (2010) 9423-9432.

E. Káfuňková, C. Taviot-Guého, P. Bezdička, M. Klementová, P. Kovář, P. Kubát, J. Mosinger, M. Pospíšil, K. Lang: Porphyrins Intercalated in Zn/Al and Mg/Al Layered Double Hydroxides: Properties and Structural Arrangement. Chem. Mater. 22 (2010) 2481-2490.

Project Funding

207/10/1447 - Photoactive hybrid materials (Czech Science Foundation)