Self-Propelled Motion of TiO2 Micron Sized Helical Particles

Thomas, Taylor J (2021) Self-Propelled Motion of TiO2 Micron Sized Helical Particles. Masters thesis, Northern Arizona University.

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Abstract

Active matter micro-particles have been observed to utilize energy to overcome Brownian motion and propel themselves. Micron to nanometer sized active matter particles have become of interest due to their potential applications ranging from drug delivery, pollutant removal, simulating biological systems and exploring emergent behaviors. Learning how to control the movement of these tiny particles is a step in understanding the phenomena of active matter particles. This thesis is concerned with controlling particle motion by empirically studying how particle chirality and material interfaces affect the motion of micron sized titanium dioxide semiconductor particles. Particle chirality is achieved through a helical tail which is grown in a physical vapor deposition system. When in a hydrogen peroxide solution and exposed to ultraviolet light, these particles will catalyze the decomposition of hydrogen peroxide and consequently cause the particles to \enquote{swim} in solution. A light microscope is used to record image sequences of these particles in action. These sequences are then processed and analyzed. Particle characterization was accomplished using a scanning electron microscope and elemental mapping was achieved through energy-dispersive x-ray spectroscopy. Results show that the chiral particles swim in circles but prefer to swim in opposite directions (clockwise or counterclockwise) with the preferred direction dependent on the particle's chirality. A difference in overall speed was also seen between the two chiralities. It was shown that a semiconductor-metallic interface changed particle speed and can change the direction in which the particles swam.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Active Matter; Colloids; Semiconductor
Subjects:	Q Science > QC Physics
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > Physics and Astronomy
Date Deposited:	07 Feb 2022 16:38
Last Modified:	07 Feb 2022 16:38
URI:	https://openknowledge.nau.edu/id/eprint/5664

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