An Experimental Study of the Impinging and Freezing Dynamics of a Colloidal Droplet on Solid Surfaces

<p>In modern manufacturing, the production of complex components with intricate geometries and varying material compositions has become essential. To meet these demands, additive manufacturing (AM) has gained prominence. Various 3D printing technologies, such as stereolithography (SLA), selective laser sintering (SLS), and plastic extrusion, have been developed to produce finished components. However, each technology has its limitations, including restricted printing resolution or limited material selection. A novel idea in additive manufacturing involves the utilization of inkjet printing nozzles with colloidal fluid and implementing the freeze-dry method. This innovative technique entails depositing colloidal droplets onto a freezing substrate using an inkjet head. The droplets freeze on the substrate and, when combined with numerous other frozen droplets, form a layer. The freeze-drying process involves sublimating the water from the frozen component. Through successive layering, the inkjet head constructs a frozen component, which is subsequently freeze-dried, resulting in a model composed of colloidal particles. This thesis focuses on observing the dynamics and thermal properties of colloidal droplets. High-speed and thermal cameras were employed to facilitate this analysis. Significant differences were observed between the final deposition patterns formed through freeze-drying and evaporation methods. Our initial hypothesis, which proposed that the deposition pattern produced by the freezing-sublimation method would be uniform rather than exhibiting a coffee ring pattern, was confirmed. Additionally, we observed that using a hydrophobic substrate during freeze-drying resulted in the formation of a spherical pattern composed entirely of colloidal particles. These findings, among others, demonstrate the feasibility of the freeze-dry method for additive manufacturing.</p>

Name thesis:degree_name

Master of Engineering (M.E.)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Mechanical Engineering

Year dc:date.available

2023

Author dc:creator

• Abdelmalek, Andro Fayek

Contributors dc:contributor

• Yang Liu

• Colloidal Droplet
• 3D Printing
• Freeze-Dry Method
• Mechanical Engineering

Repository record dc:identifier

https://academicworks.cuny.edu/cc_etds_theses/1139

OAI identifier oai:identifier

oai:academicworks.cuny.edu:cc_etds_theses-2164