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Bactericidal and hydrophilic plasma deposited thin TiO2 films on glass substrate

Sobczyk-Guzenda A., Szymanowski H., Gazicki-Lipman M., Kowalski J., Jakubowski W., Halamus T.

Engineering of Biomaterials

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2009

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Vol. 12, no. 85

8--12

EN

In recent years, titanium dioxide has attracted a great deal of attention as a material for photocatalytic applications. These applications include antibacterial effect as well as photocatalytic air and water purification. Another property of TiO2 concerns a substantial increase of its surface hydrophilicity upon irradiation. The aim of this work is to investigate thin TiO2films obtained by RF PECVD technique with respect to hydrophilic and long-term bactericidal activity. Structural studies, carried out by Raman spectroscopy show that all the investigated coatings are amorphous. The films exhibit agglomerates, with their amount depending on energetic conditions of deposition. Adhesion measured by a scratch test shows that films deposited at higher RF power adhere better than those synthesized at lower power values. UV irradiation causes death of nearly 100% of Escherichia coli population on TiO2films. The irradiated films are still active for about 30 min after the end of UV exposure. A substantial decrease of water contact angle is also observed upon the irradiation of the films with UV light.

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Mesomorphic organisation of (2-hydroxypropyl)cellulose under the influence of silica networks

Wojciechowski P., Halamus T., Pietsch U.

Materials Science Poland

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2006

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Vol. 24, No. 2/2

507--516

EN

Mesomorphic behaviour of (2-hydroxypropyl)cellulose (HPC) within organic-inorganic hybrid materials was investigated. Hybrid materials HPC/silica were prepared by means of the sol-gel process, with hydrolysis and condensation of (tetraethoxy)silane taking place in the mesomorphic environment of HPC. Solid films of HPC/silica were investigated using the Raman spectroscopy, differential scanning calorimetry, thermo-optical analysis, and small angle X-ray scattering. Additionally, swelling by water was tested. The analysis of the results leads to the following conclusions: (i) silica has a strong stabilisation effect on the mesomorphic organisation of HPC: the glass transition temperature and isotropisation temperature of HPC are shifted to higher values; (ii) X-ray measurements reveal a nano-scale organisation of the HPC/silica hybrids with d-spacing equal to 65A; a long-range organisation within HPC/silica hybrids seems to be related to a surface induced ordering; (iii) curing of HPC/silica hybrids affects the swelling behaviour. s.

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Wytwarzanie nanokrystalicznych warstw tlenku cynku przy użyciu prekursora hybrydowego

Bobowska I., Halamus T., Wojciechowski P.

Inżynieria Materiałowa

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2006

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Vol. 27, nr 6

1329-1332

PL

Przedstawiono sposób wytwarzania cienkich warstw nanokrystalicznego tlenku cynku metodą zol-żel przy użyciu prekursora hybrydowego, w skład którego wchodzą: octan cynku (znAc) oraz (2-hydroksypropy-lo)celuloza (hpc). Wykazano, że w układzie hybrydowym ZnAc/HPC jony cynku koordynują nie tylko jony octanowe ale również grupy wodorotlenowe, pochodzące od (2-hydroksypropylo)celulozy. W procesie zol-żel ZnAc w obecności HPC i trietyloaminy otrzymano kserożel w postaci filmu na podłożu szklanym. Wygrzewanie kserożelu w 170 °c prowadzi do krystalizacji tlenku cynku w matrycy HPC. W wyniku mineralizacji termicznej kserożelu w 600 °C otrzymano nanokrystaliczne filmy ZnO. Do badań wykorzystano spektroskopię ramanowską, analizę rentgenowską oraz skaningowy mikroskop elektronowy. Widma Ramana przedstawione na rys. 1 i rys. 3, ilustrujące wyniki analizy układu hybrydowego znAc/hpc oraz znAc/glikol etylenowy, wykazały efekt koordynacji grup OH (2-hydroksypropylo)celulozy przez jony cynku. Rys. 4 ilustruje widmo Ramana kserożelu oraz przebieg krystalizacji ZnO w procesie wygrzewania kserożelu w 170 °C. Mineralizacja termiczna kserożelu w 600 °C umożliwia otrzymanie transparentnej warstwy ZnO o strukturze nanokrystalicznej, potwierdzonej badaniami ramanowskimi (rys. 5), rentgenowskimi (rys. 6) oraz SeM (rys. 8).

EN

The method of synthesis of zinc oxide thin nanocrystalline films by solgel technique has been presented. A hybrid precursor composed of zinc acetate (ZnAc) and (2.hydroxypropyl)cellulose (HPC ) was used in solgel process. It was found that, zinc ions in the hybrid system ZnAc/HPC coordinate not only acetate ions, but also hydroxide groups of HPC . Films of xerogel were obtained by sol-gel process of ZnAc in presence of HPC and triethylamine on glass substrate. Annealing of xerogel at170 degree C leads to ZnO crystallization in HPC matrix. In the effect of thermal mineralization of xerogel at 600 degree C nanocrystalline and transparent film of ZnO was obtained. Raman spectroscopy, X-ray analysis and scanning electron microscopy were used in our investigations. In the Fig. 1 and Fig. 3 the Raman spectra of hybrid systems of ZnAc/ HPC and ZnAc/ethylene glycol have been presented, respectively. They show effect of coordination OH groups of (2.hydroxypropyl)cellulose by zinc ions. Raman spectra of xerogel and process of crystallization of ZnO during annealing of xerogel at 170 degree C are shown in the Fig. 4. Thermal mineralization of xerogel at 600 degree C facilitates to obtain transparent ZnO layer with nanocrystalline structure, what was confirm by Raman (Fig. 5), X-ray (Fig. 6) and SEM (Fig. 8) analysis.