"Printing and Cold Plasma-Assisted Deposition of Conductive Polymer Blends and Nanocomposites" 

Ulisses Alberto Heredia Rivera, MSE PhD Candidate 

Advisor: Professor Rahim Rahimi

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ABSTRACT

For many years, polymers were known to be flexible and electrical insulating materials. However, the discovery of conductive polymers, and its further recognition with the 2000’s Nobel Prize in Chemistry, changed forever the perception of polymers in the material science community. Since then, the continuous progress in conductive polymer research has made possible the development of many organic, flexible, and printed devices including organic solar cells, flexible displays, and low-cost printed sensors. Conductive polymers such as polypyrrole, polyaniline, and PEDOT: PSS are a special group of polymers that are indeed capable of conducting electricity. Despite the numerous potential applications of conductive polymers, some important challenges regarding processability, mechanical performance, and reliability remain. To address these issues, conductive polymers are often blended or synthesized as nanocomposites resulting in materials with enhanced performance and processability. Nevertheless, their processability is always challenging, involving time-consuming and multistep manufacturing affecting their full potential in commercial products. Therefore, this dissertation explores the synthesis, processability, and material performance of conductive polymer blends and nanocomposites utilizing two scalable additive approaches: 1) printing and 2) in-situ synthesis and direct deposition. The first part of this dissertation introduces the use of conductive polymer blends based on the conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate or PEDOT: PSS combined with scalable printing technologies to develop low-cost printed sensors. For the first time, conductive polymer blends of PEDOT: PSS combined with polyvinyl alcohol and polyurethane were optimized as radiation sensing materials utilized in low-cost printed radiation sensors with applications in the sterilization assessment of medical devices. In the second part of this dissertation, conductive polymer nanocomposites derived from polypyrrole were successfully synthesized and deposited onto flexible substrates by cold atmospheric plasma deposition for multipurpose applications including printed sensors and antibacterial coatings for wearable electronics. These contributions mark a new stepping stone toward scalable additive manufacturing of conductive nanocomposite films for different organic, printed, and flexible electronic applications.