Graduate Studies

 

First Advisor

Stephen A. Morin

Degree Name

Doctor of Philosophy (Ph.D.)

Committee Members

Alexander Sinitskii, David Hage, Ruiguo Yang, Yinsheng Guo

Department

Chemistry

Date of this Version

4-2025

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Doctor of Philosophy

Major: Chemistry

Under the supervision of Professor Stephen A. Morin

Lincoln, Nebraska, April 2025

Comments

Copyright 2025, John M. Kapitan. Used by permission

Abstract

The demands of emerging technologies, such as soft robotics, stretchable electronics, and next generation biomedical implants, has led to the development of diverse polymeric and hybrid organic/inorganic materials specifically tuned to meet these challenges. These materials typically have low Young’s moduli and are inert with high chemical stability. However, this has led to materials that are static in nature, lacking any meaningful way of responding to changes in their environment and adapting to these changes. This has driven a shift towards the design, manufacturing, and characterization of various stimuli responsive surfaces, relying on precise control of surface chemical coatings and microstructuring, leveraging the mechanical compliance of the bulk to unlock different responsive states. For instance, derivatization of elastomeric nanofibrillar grafts with an anti-thrombotic agent was achieved for surgically implantable and mechanically compliant arterial stents. These stents possess mechanical properties like those found in natural tissue and the presence of heparin prevented blood clotting in vivo.

Hydrogels can be easily derivatized with stimuli responsive moieties and have emerged as excellent candidates for various applications. Due to the large weight fraction of water hydrogels possess, they often lack the necessary mechanical properties for practical implementation. Selectively derivatizing an elastomer support material allowed photografting of various stimuli responsive hydrogels without sacrificing their natural stimulus response. This also enabled the application of hydrogel hybrid materials in liquid environments. The work described in this dissertation demonstrates the benefits that rational control of both surface chemistry and microstructure for applications such as biomaterial engineering, soft robotics, and optical sensors.

Advisor: Stephen A. Morin

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