Date Approved

2024

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department or School

Physics and Astronomy

Committee Member

Weidian Shen, PhD

Committee Member

Patrick Koehn, PhD

Committee Member

Eric Paradis, PhD

Abstract

The purpose of this research was to compare mechanical and tribological properties of a coatingto the same coating with added nano silica. The sample coating for this project was bis-ureasil which was synthesized using 1:1 equivalent ratio of bis (3-trimethoxysilyl-propyl) amine (BTMSPA) (318.0g) and IPDI (52.0g) in 400g of anhydrous THF. The other coating was prepared by adding 10% nano silica particles. A scanning probe microscope was used to study the surface morphology of the coating samples, a Raman microscope was used to study the silicon concentration on and underneath the surface of the coating, and nano-indentation was used to compare the mechanical characteristics of the coating samples. Images obtained from the scanning probe microscope indicated no significant difference between surfaces of the two coating samples with and without nano silica, revealing that the added nano silica diffused into the coatings and embedded underneath the surface. A number of silicon peaks observed with Raman microscope suggested that the coating with added nano silica had slightly higher silicon concentration, as expected. The silicon peaks of almost equal heights at different depths for the coating with nano silica indicated that the added nano silica diffused throughout the coating. A number of nano-indentation tests revealed that the coating sample with added nano silica has higher modulus of elasticity and hardness at each depth. The scratch width produced under the same applied force was higher in the coating sample without nano silica. Similarly, the real scratch depth and the residual effect of the forces applied on the coating sample with added nano silica were lower. These observations revealed that the scratch strength of the coating is increased when nano silica particles are added. Thus, added silicon particles strengthen the mechanical and tribological properties of polymeric coatings, enhancing the hardness, elastic modulus and scratch resistance.

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