Date of Award
Doctor of Philosophy
Material Science and Engineering
Dr Felicia S. Manciu
Inorganic potassium dihydrogen phosphate (KDP) is widely known for its value as a nonlinear optical material. In this study, pure and l-arginine-doped KDP single crystals were grown by the slow solvent evaporation technique and further subjected to infrared absorption and Raman studies for the confirmation of chemical group functionalization and possible bonding between the organic and inorganic materials. The appearance in the infrared absorption spectra of additional vibrational lines, which mostly originate from disturbed N-H, C-H, and C-N bonds of the l-arginine-doped salt, confirm the interaction between KDP and the organic material. This affirmation is supported by more evidence from Raman measurements, where the disappearance of NH vibrations of the amino group is observed. We are thus led to the possibility of hydrogen bonding primarily between the nucleophilic O- of the phosphate unit of KDP and the amino group of the l-arginine. These crystals were also subjected to powder X-ray diffraction for crystal structure determination. Furthermore, we also performed the thermo gravimetric analysis to study effect of L-arginine doping on the thermal stability of the grown KDP crystals.
Although herbal medicine is widely employed in inhibition of urinary calculi as an alternative and complementary curative method, the lack of detailed scientific studies that could provide insights into this complex process weakens its validity. The present work targets multi-technique spectroscopic investigations by Raman, infrared absorption, X-ray photoelectron spectroscopy (XPS), and photoluminescence on the effects of the herb Rotula Aquatica Lour (RAL) on the growth of synthetically prepared manganese-based calculi. In addition to the standard magnesium phosphate - based sample, two other samples were prepared with incorporation of 1% and 2% wt.% RAL herbal extract. Both, Raman and infrared data show a newberyite structure for the crystals without and with inhibitor. The XPS measurements reveal an unexpected presence of Zn in the sample with RAL inhibitor, which, as suggested in the literature, may initiate rapid stone formation, and consequently, contribute to the inhibition process. Furthermore, the existence of metallic Zn can explain the reflectance of the incident light observed in the infrared transmission studies of the unground crystals. A significant increase in magnesium with addition of herbal extract is observed in the XPS data. Also, evidence for Mg-O binding between the inhibitor and the phosphate units of urinary calculus is found in XPS and Raman results. Similarity between our photoluminescence measurements and those of in vivo chlorophyll a corroborates to provide additional evidence of Mg-related inhibition.
Received from ProQuest
Jayesh Rasikalal Govani
Govani, Jayesh Rasikalal, "Spectroscopic Characterizations of Organic/Inorganic Nanocomposites" (2009). Open Access Theses & Dissertations. 270.