Titanium (IV) Oxide Nanotubes in Design of Active SERS Substrates for High Sensitivity Analytical Applications: Effect of Geometrical Factors in Nanotubes and in Ag-n Deposits

In this chapter, we summarize the results of recent investigations into TiO2 nanotubular oxide layers on Ti metal loaded with Ag nanoparticles, which act as efficient surface plasmon resonators. These Ag-n/TiO2 NT/Ti composite layers appear to be useful as platforms for precise surface analytical investigations of minute amounts of numerous types of organic molecules: pyridine (Py), mercaptobenzoic acid (MBA), 5-(4-dimethylaminobenzylidene) rhodamine (DBRh) and rhodamine (R6G); such investigations are known as surface enhanced Raman Spectroscopy (SERS). Geometrical factors related to the nanotubes and the silver deposit affect the SERS activity of the resulting composite layers. The results presented here show that, for a carefully controlled amount of Ag-n deposit located mainly on the tops of titania nanotubes, it is possible to obtain high-quality, reproducible SERS spectra for probe molecules at an enhancement factor of 105–106. This achievement makes it possible to detect organic molecules at concentrations as low as, e.g., 10−9 M for R6G molecules. SEM investigations suggest that the size of the nanotubes, and both the lateral and perpendicular distribution of Ag-n (on the tube tops and walls), are responsible for the SERS activity. These features of the Ag-n/TiO2 NT/Ti composite layer provide a variety of cavities and slits which function as suitable resonators for the adsorbed molecules

Unity of contemplation and action in the life of Wanda Malczewska

The life of Wanda Malczewska provides a perfect example of how a life of contemplation, or vita contemplativa, can be harmoniously combined with one of social action, or vita activa. This distinguished Polish mystic, born in Radom in 1822, always managed to reconcile prayer and personal communion with God with her work on behalf of others. Malczewska was both an ardent Christian and a patriot. Her love of God and of her neighbours impelled her to perform acts of mercy on a large scale, bringing relief to those in need, and in this work she was tireless: she taught children and teens, with a view towards their future; she gave financial help to those who couldn’t afford schooling; she cared for and supported the broken in spirit; she instructed the unskilled; she acted as mediator, reconciling embittered married couples and feuding neighbours. In a word – she was an extraordinary character, completely devoted to serving God and her fellows. She lived in times that were difficult for Poland and the Polish people, when their country had been partitioned. This fact further hindered the many difficult tasks she had set herself, for the occupying powers introduced various restrictions aimed at weakening or eliminating Polish culture. At the time of her death in 1896, Wanda Malczewska was already popularly considered to be a saint. Efforts to have her so declared officially were commenced in 1924 by Father Grzegorz Augustynik, who had known Malczewska personally and was convinced of her saintliness. On 26 June 2006, Pope Benedict XVI authorised the promulgation of a decree on the heroic virtues of Servant of God Wanda Malczewska. This was an important decision in light of the efforts being made to bring the process of beatification of this exceptional person to a fruitful conclusion

Ag/ZrO2Ag/ZrO_2-NT/Zr hybrid material : a new platform for SERS measurements

In this paper, we present recent results of our attempts to produce nanoporous zirconia, as well as our investigations of a hybrid material consisting of nanoporous zirconia loaded with Ag-nanoparticles, Ag- n/ZrO 2 -NT/Zr, which could be used as an active SERS substrate. The Zr-based hybrid material, as our investigations have shown, is an active and stable substrate in SERS investigations aimed at detecting various organic molecules: mercaptobenzoic acid, pyridine and two different dyes – rodhanine deriva- tives. The SERS spectra for the probe molecules adsorbed on silver nanoparticles on a ZrO 2 -NT/Zr platform display characteristic intensity ratios different from those measured on previously studied nanoporous substrates based on Ti and Al, which ensure a different (alternative) interaction between the investi- gated adsorbate and adsorbent. In order to characterize our new substrate we used high-resolution SEM and surface analytical techniques: XPS (X-ray photoelectron spectroscopy) and SERS (surface enhanced Raman spectroscopy)