SUBJECT: Ph.D. Dissertation Defense
BY: Tae Joong Jeong
TIME: Wednesday, June 8, 2022, 11:00 a.m.
TITLE: Enabling a Scalable Manufacturing Approach to Fabricate Functional Gradated Polymer Thin Films
COMMITTEE: Dr. Tequila Harris, Chair (ME)
Dr. Alexander Alexeev (ME)
Dr. YongTae (Tony) Kim (ME)
Dr. Suresh Sitaraman (ME)
Dr. Carson Meredith (ChBE)


Polymer thin films with a cross-web gradient structure, is a burgeoning area of research, having received more attention in the last two decades, for improvements in performance and material properties. Such patterned films have been fabricated using several techniques, which in practice, these techniques are not scalable, material dependent, wasteful and not highly efficient. In this thesis, the feasibility of using slot die coating, a well-known scalable manufacturing process, to fabricate gradated polymer thin films will be investigated. The proposed work incorporates slot die with custom roll-to-roll imaging system to successfully fabricate gradated thin film by forcing two fluidic materials into the slot die simultaneously and by manipulating the viscous, diffusion and inertial forces. The materials will be allowed to intermix, with the aim of having approximately a 50% mix along the centerline of any two contiguous stripes. Moreover, several characterizations are performed to assess the quality of the gradated polymer thin films. Here, several well-known functional materials are used as part of the gradient structure to fabricate functional gradient structures, which then are used to prove the practicality of such pattern. Furthermore, mathematical analysis is conducted to understand the mechanisms that drive the mixing or diffusion between the materials to form the gradient structures, the limitations on feature size, and the structure-property relationships relative to system inputs. Computational analysis is used to support the experimental results. These investigations will provide a fundamental understanding of the mechanisms that can be controlled to obtain gradated polymer thin films structures that exhibit the desired geometric structure, mechanical properties, and performance.