(3dd) Rheology-Guided Development and Modulation of Soft Materials

Understanding of and control over a material’s mechanical properties is crucial to consistently achieving its desired function and performance. I am currently seeking a postdoctoral research position in the area of soft material development, to which I can apply the understanding of rheology gained during my graduate studies to engineer functional and mechanically robust materials.

Research Experience

Graduate Research Advisor: Dr. Saad Khan, Department of Chemical and Biomolecular Engineering, North Carolina State University

My doctoral research has centered around applying rheological measurement techniques to complex and dynamic soft materials. During my PhD (which I am defending in Fall 2020), I have worked on projects involving a variety of materials, including photocurable polymer nanocomposites, drug delivery gels, and polyester powder coatings; however, my efforts have been concentrated in the two research thrusts listed below.

In the first research thrust, I used rheology to quantify in vivo enzymatic degradation of uterine fibroids and xenograft breast cancer tumors to evaluate the effectiveness of novel injectable collagenase treatments on softening tissues and reducing metastasis. The treatments included co-injection of a thermoresponsive, hydrolyzable NIPAM-based copolymer which gels at physiological temperatures to reduce collagenase diffusion from the injection site, allowing for sustained enzyme activity. Using rheology, I demonstrated that these injectable treatments can significantly reduce the modulus and increase the viscoelasticity of both benign (uterine fibroid) and metastatic (breast cancer) tumors. With collaborators at Duke and North Carolina Central Universities, we have then related the mechanical response to the physiological response (extracellular matrix degradation, protein expression, tumor metastasis, etc.) to gain a more complete understanding of treatment effects on soft tissues.

The second research thrust seeks to understand how ultraviolet (UV) light affects coordinated ionic liquids (ILs) containing reactive vinyl groups, which provide a tunable medium for bulk polymerization and network formation. Rheology was used to monitor the in situ photopolymerization of coordinated ILs containing varying vinylimidazoles and metal bistriflimide salts. At intermediate salt concentrations, coordinated ILs became gels after UV light exposure due to coordination-induced physical crosslinking between growing polymer chains. I also demonstrated how parameters such as UV light intensity, exposure time, and molecular architecture affected material response to demonstrate the tunability of this class of materials. The more thorough understanding of material behavior during photopolymerization gained from this work can then be used to help engineer photocured IL-based systems with tailored mechanical properties for applications such as battery polyelectrolytes and chemical-resistant coatings and adhesives.

Funding Sources: NSF Graduate Research Fellowship, GAANN Fellowship in Molecular Biotechnology

Selected Publications

Corder R.D., Dudick S.C., Bara J.E., & Khan S.A. “Photorheology and Gelation During Polymerization of Coordinated Ionic Liquids.” ACS Appl. Polym. Mater. 2020, 2 (6), 2397-2405.

Corder R.D., Tilly J.C., Ingram W.F., Roh S., Spontak R.J., & Khan S.A. “Rheology of UV-Curable Polymer Nanocomposites Based on Poly(dimethyl siloxane) and Zirconia Nanoparticles: Role of Reactive vs. Passive Fillers.” ACS Appl. Polym. Mater. 2020, 2 (2), 394-403.

Wang J., Ye Y., Yu J., Kahkoska A.R., Zhang X., Wang C., Sun W., Corder R.D., Chen Z., Khan S.A., and Gu Z. “Core-Shell Microneedle Gel for Self-Regulated Insulin Delivery.” ACS Nano, 2018, 12 (3), 2466-2473.

Domier R.C., Moore J.N., Shaughnessy K.H., and Hartman R.L. “Kinetic Analysis of Aqueous-Phase Pd-Catalyzed, Cu-Free Direct Arylation of Terminal Alkynes Using a Hydrophilic Ligand.” Organic Process Research & Development, 2013, 17 (10), 1262-1271.