Date of Award

Spring 2026

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics

Committee Director

Sebastian Kuhn

Committee Member

Peter Bernath

Committee Member

Alexander Godunov

Abstract

Mechanochemistry is the study of chemical reactions driven by the input of mechanical en ergy in addition to thermal activation. Mechanochemical reactions from powders are carried out by manual grinding or milling using various types of ball mills, or in twin extruders. While mechanochemistry has great potential affording economically and environmentally advantageous “green” synthetic methods, a drawback is that its chemical mechanisms are not well understood. One example of such a reaction currently under study involves tetrathiafulvalene, an organic elec tron donor with two polymorphs (orange and brown), and chloranilic acid, an electron acceptor. Previous results show that neat grinding the orange form of tetrathiafulvalene with chloranilic acid in a mortar and pestle leads to a neutral charge transfer complex. We hypothesized that ball milling these reactants would deliver larger mechanical energy doses per time unit inducing the formation of a known ionic form of the charge transfer complex. Hence, the kinetic profiles at 15, 20, and 30 Hz milling frequencies were measured. Quantitative phase analysis was carried out from labora tory X-ray powder diffraction data, using the internal standard method. As expected, an increase of the milling frequency increases the reaction rates. The neutral charge transfer complex is initially formed, and then it transforms to the ionic polymorph. The milling times at which the neutral or the ionic forms are found as the reaction product vary with the milling frequency as well. Addi tionally, we found evidence of a short lived oscillating reaction in which the neutral converts to ionic and back to neutral multiple times depending on the milling frequency.

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DOI

https://doi.org/10.25777/0j3v-ak74

ISBN

9798197810519

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