Molecular probing of vicosity, temperature, pressure and microscopic friction
Abstract
This thesis is a contribution to the application of the spectroscopic properties of molecules to obtain information about the viscosity, temperature, pressure and microscopic friction of a molecule in various solutions. Spectroscopy can be used to obtain viscosity, temperature and pressure data. The depolarization of the fluorescence of the molecule, BTBP, is not only proportional to the viscosity of both normal alkanes and alcohols in which it is dissolved, but also shows the same relationship in ethanol/glycerol and dodecane/mineral oil mixtures. The Raman frequency shifts of the solvent molecule, methylcyclohexane, are sensitive to the surrounding pressure while the anti-Stokes/Stokes ratio of vibrational modes of chloroform and polydimethylsiloxane are related to temperature. In addition, the blue tail of the fluorescence of BTBP can relay temperature information. Rotational diffusion experiments are detailed along with results for both charged and neutral nile blue along with nile red establish the importance of charge and unimportance of substituent groups on microscopic friction. A review of the literature pertaining to rotational diffusion is also given and is used to empirically relate rotational diffusion a molecule to its volume. Lastly, the rotational motion of BTBP at high pressures was also studied.
Degree
Ph.D.
Advisors
Ben-Amotz, Purdue University.
Subject Area
Analytical chemistry|Chemistry
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