Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Polymer Science and Engineering

Committee Chair

Xiaodan Gu

Committee Chair School

Polymer Science and Engineering

Committee Member 2

Sergei Nazarenko

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

Zhe Qiang

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Song Guo

Committee Member 4 School

Biological, Environmental, and Earth Sciences

Committee Member 5

Boran Ma

Committee Member 5 School

Polymer Science and Engineering


Significant efforts have been dedicated to the development of high-performance organic electronic materials, endowed with novel attributes that traditional inorganic silicon-based electronics cannot provide. Conjugated polymers stand out as the predominant class of organic semiconducting materials, offering a unique avenue to manufacture flexible, ductile, large-area, and customizable electronic devices through cost-effective solution processing. Despite the extensive array of processing methods, there remains a significant gap in our understanding of the dynamic and thermodynamic properties of conjugated polymer solutions and thin films. This dissertation endeavors to unravel the intricate structure-property-processing relationships of these materials by delving into their mechanical, dynamic, and thermodynamic characteristics across a spectrum of conjugated polymers. The dissertation is organized into three distinct segments.

In the first segment, we probe the factors influencing stress relaxation in thin films by conducting direct stress relaxation experiments under varying conditions, such as temperature, film thickness, and the glass transition temperature of the polymers. Our findings reveal that conjugated polymers have a fast stress relaxation rate, and the polymer-air and polymer-water interfaces expedite the rate of stress relaxation in the thin glassy film.

In the second segment, we delve into the chain conformation of ladder polymers, a novel class of conjugated polymers distinguished by double strains of chemical bonds along their backbones. We employ scattering techniques and other methodologies to characterize their structures. Our observations highlight that the rigid backbone of ladder polymers curtails the entropy of dissolution, consequently restricting the solubility of these unique materials.

In the third segment, we investigate the impact of solvent quality on various conjugated polymers with distinct architectures. Our approach involves the use of static light scattering and other analytical techniques. We discern that the volume fraction and architecture of side chains significantly influence solution conformation. Notably, our research underscores the strong stacking propensity of conjugated polymers in solution, which can impede their solubility.

In the fourth segment, we invested the impact of chain rigidity on the solution diffusion dynamics of conjugated polymer chains through a comprehensive light scattering analysis. CPs are less rigid in good solvents like chlorobenzene but more rigid in bad solvent toluene. And ladder type CPs have the most rigid backbone with stiff rod like diffusion behavior.

In summary, this dissertation offers a comprehensive exploration of the mechanical, dynamic, and thermodynamic attributes of conjugated polymers, both in the context of thin films and solutions. The insights gained through this research are poised to inform the design and processing of conjugated polymers and organic electronic devices, enhancing our ability to harness their full potential.


Available for download on Sunday, June 01, 2025