Institutional Repository
The UDSpace Institutional Repository collects and disseminates research material from the University of Delaware.
- Faculty, staff, and graduate students can deposit their research material directly into UDSpace. Faculty may use UDSpace to fulfill the University of Delaware Faculty Senate Open Access Resolution, and in many cases may use it to fulfill open access requirements from grant funding agencies.
- Departments can use UDSpace to publish or distribute their working papers, technical reports, or other research material.
- UDSpace also includes all doctoral dissertations from winter 2014 forward, and all master's theses from fall 2009 forward.
To learn more about UDSpace, and how you can make your research openly accessible to the public, visit our UDSpace Policies website.
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Recent Submissions
“Freedom and Slavery at Delaware College: A Student Research Symposium”
(University of Delaware Library, Museums and Press, 2024-12) Professors Laura E. Helton and Dael A. Norwood, joined by their students
Formation of bijels stabilized by magnetic ellipsoidal particles in external magnetic fields
(Soft Matter, 2024-10-08) Karthikeyan, Nikhil; Schiller, Ulf D.
Bicontinuous interfacially-jammed emulsion gels (bijels) are increasingly used as emulsion templates for the fabrication of functional porous materials including membranes, electrodes, and biomaterials. Control over the domain size and structure is highly desirable in these applications. For bijels stabilized by spherical particles, particle size and volume fraction are the main parameters that determine the emulsion structure. Here, we investigate the use of ellipsoidal magnetic particles and study the effect of external magnetic fields on the formation of bijels. Using hybrid Lattice Boltzmann-molecular dynamics simulations, we analyze the effect of the magnetic field on emulsion dynamics and the structural properties of the resulting bijel. We find that the formation of bijels remains robust in the presence of magnetic fields, and that the domain size and tortuosity become anisotropic when ellipsoidal particles are used. We show that the magnetic fields lead to orientational ordering of the particles which in turn leads to alignment of the interfaces. The orientational order facilitates enhanced packing of particles in the interface which leads to different jamming times in the directions parallel and perpendicular to the field. Our results highlight the potential of magnetic particles for fabrication and processing of emulsion systems with tunable properties.
Visualizing separation at composite interfaces via spirolactam mechanophores
(RSC Mechanochemistry, 2024-10-17) Gohl, Jared A.; Roberts, Tyler J.; Freund, Anna C.; Haque, Nazmul; Rueschhoff, Lisa M.; Baldwin, Luke A.; Davis, Chelsea S.
The failure of interfaces between polymers and inorganic substrates often leads to deteriorated performance, as is the case for polymer matrix composites. Interfacial mechanophores (iMPs) have the potential to fluorescently measure interfacial failures. Spirolactam-based mechanophores are of interest due to their readily available synthetic precursors and compatibility with epoxy matrices. In this work, spirolactam is covalently bound at the interface of silica surfaces and epoxy, chosen due to the industrial relevance of glass fiber composites. The iMPs are mechanically activated through uniaxial tension applied to the composite while the resulting fluorescent response is observed in situ with a confocal microscope. Due to their real time sensing capabilities, iMPs are a promising technique to measure interfacial failures in composite materials more easily than with traditional optical microscopy techniques.
Zonal patterning of extracellular matrix and stromal cell populations along a perfusable cellular microchannel
(Lab on a Chip, 2024-10-21) Chernokal, Brea; Ferrick, Bryan J.; Gleghorn, Jason P.
The spatial organization of biophysical and biochemical cues in the extracellular matrix (ECM) in concert with reciprocal cell–cell signaling is vital to tissue patterning during development. However, elucidating the role an individual microenvironmental factor plays using existing in vivo models is difficult due to their inherent complexity. In this work, we have developed a microphysiological system to spatially pattern the biochemical, biophysical, and stromal cell composition of the ECM along an epithelialized 3D microchannel. This technique is adaptable to multiple hydrogel compositions and scalable to the number of zones patterned. We confirmed that the methodology to create distinct zones resulted in a continuous, annealed hydrogel with regional interfaces that did not hinder the transport of soluble molecules. Further, the interface between hydrogel regions did not disrupt microchannel structure, epithelial lumen formation, or media perfusion through an acellular or cellularized microchannel. Finally, we demonstrated spatially patterned tubulogenic sprouting of a continuous epithelial tube into the surrounding hydrogel confined to local regions with stromal cell populations, illustrating spatial control of cell–cell interactions and signaling gradients. This easy-to-use system has wide utility for modeling three-dimensional epithelial and endothelial tissue interactions with heterogeneous hydrogel compositions and/or stromal cell populations to investigate their mechanistic roles during development, homeostasis, or disease.
Random field reconstruction of three-phase polymer structures with anisotropy from 2D-small-angle scattering data
(Soft Matter, 2024-10-14) Kronenberger, Stephen; Gupta, Nitant; Gould, Benjamin; Peterson, Colin; Jayaraman, Arthi
In this paper we present a computational method to analyze 2-dimensional (2D) small-angle scattering data obtained from phase-separated soft materials and output three-dimensional (3D) real-space structures of the three types of domains/phases. Specifically, we use 2D small-angle X-ray scattering (SAXS) data obtained from hydrated NafionTM membranes and develop a workflow using random fields to build the 3D real-space structure comprised of amorphous hydrophilic domains, amorphous polymer domains, and crystalline polymer domains. We demonstrate the method works well by showing that the reconstructed 3D NafionTM structures have a computed scattering profile that matches the input experimental scattering profile. Though not demonstrated in this work, such reconstructions can be used for further analysis of domain shapes and sizes, as well as prediction of transport properties through the structure. Our method in this work extends capabilities beyond the previously published random field small angle scattering reconstruction method introduced by Berk [Phys. Rev. Lett. 1987, 58 (25), 2718–2721] that had been used to reconstruct structures from 1D small angle scattering data of two-phase systems. The method in this work can be used to generate isotropic, two-phase reconstructions, but can also handle 2D SAXS profiles from three-phase systems that have structural anisotropy resulting from material processing effects.