Pole tekstowe: Research areas center around nanotechnological issues related to the development and new applications of sol-gel derived ceramic materials and composites in the following aspects: 
I. Sol-gel materials: 
porous materials
thin films and coatings
composites
II. Physico-chemical surface modification.
III. Tribology of sol-gel materials.

Porous materials:
Initially our research was focused on synthesis and characterization of mesoporous siliceous materials having high specific surface area (1000m2/g and more) having uniform distribution of pores with the diameter of 2-4 nm. Such materials additionally functionalized with organic groups grafted to the walls or directly incorporated inside the pores find application in adsorption (eg. recovering of heavy metal ions from waste water), purification techniques and as host materials for further synthesis. This work was mainly realized in cooperation with LAMMI laboratory at the University Montpellier II in France.
At present, part of our research activity is devoted to the preparation of macroporous coatings having diameter of pores in the range of several hundreds of nanometers – typically 200-400nm. Macroporous materials are excellent candidates in photoelectronics and as photonic crystals. The synthesis of such materials is based on application of polymer beads (PMMA in our case) as templates and sol-gel reactions. Final material is prepared after removing the polymer template upon extraction or calcination.

Thin films and coatings:
Experiences gained during the synthesis and characterization of porous materials were extended to the preparation of sol-gel derived materials in the form of thin coatings (~10-200 nm). The preparation of thin coatings covers such materials like titania, alumina, zirconia, silica, vanadia, and others. In this approach metaloorganic compounds are used as precursors in preparation of ceramic coatings on silicon wafers in sol-gel dip-coating deposition method. In particular titania coatings are in the center of interest due to its numerous applications in photocatalysis, energy conversion, food and pharmaceutical applications, medical implants etc.

Composites:
Another area of investigation is related the application of ceramic or metallic nanoparticles for preparation of composites. Corundum, zirconia, titanium nitride and diamond nanoparticles dispersed in titania sol-gel coatings form isotropic biphase or multilayer coatings. Isotropic biphase is realized by direct dispersing the nanophase in a zol containing appropriate ceramic precursor. Multilayered composite is realized by successive deposition of sol-gel layer and nanoparticle layer.
Besides tribological studies, photcatalytic properties of sol-gel titania coatings are studied. In this area, the possibilities of creating metal nanostructures on titania surface by in-situ method upon UV irradiation is studied. It is well known that silver-titania coupling materials have strong antibacterial and self-cleaning properties. This approach can also be used in preparation of multilayer ceramic-metallic composites.

Physico-chemical surface modification:
Physico-chemical surface modification is performed in liquid or vapor phase. The objective of the surface modification is tuning its properties such as wettability, adhesion, friction etc. Other auxiliary techniques are also employed in this area such as low temperature plasma, UV irradiation, high temperature treatment etc. Self-assembly, Langmuir-Blodgett and dip-coating deposition techniques of organic modifiers are usually applied. Zinc dialkyldithiophosphate (ZDTP), perfluoroderivatives as well as other compounds are mainly used as modifiers.

Tribology of sol-gel materials:
The growing number of publications and reports related to tribological aspects of sol-gel derived materials has been observed recently. Tribological properties of sol-gel thin films have been intensively investigated also in our group for several years. The influence of porosity and chemical modification of the surface on wear and frictional properties of silica, zirconia, alumina and titania films are studied by means of microtribometer, Atomic Force Microscopy and other microscopic techniques.
It was found that the presence of porosity which is often required for enhancing the catalytic performance of ceramics (eg. titania) negatively influences the wear resistance of the coating. 
Application of friction modifiers on the surface of titania ceramic coatings enhances the frictional properties reducing friction coefficient and wear in frictional contacts. 

Contact
Ireneusz Piwoński, DSc, PhD
Aneta Kisielewska, PhD
tel. (+48 42) 635 58 33
Pole tekstowe: Nanotechnological issues, development and new applications of sol-gel derived ceramic materials and composites 
nanotechnology research

Porous TiO2 thin layer (AFM image)