Home Institution: Augsburg University
REU Faculty Advisor: Xiang Cheng, Moumita Dasgupta
REU Mentor: Chijing Zang
Macro-Scale Experimental Study of Torque-Induced Precession in a Flagellar Hook Analog
Bacteria such as Escherichia coli swim by rotating helical flagellar filaments connected to a molecular rotary motor via a flexible hook that acts as a universal joint. This hook transmits torque from the motor to the filament while allowing it to spin at a tilt angle, producing a precessional motion, a simultaneous spin and revolution, that is fundamental to bacterial propulsion at low Reynolds number. While the physics of torque-induced precession has been explored theoretically and computationally, direct experimental observation remains challenging due to the nanometer scale of the flagellar system. Previous work in our lab constructed a macro-scale flagellar analog connected to a universal joint and demonstrated a clear relationship between fixed tilt angle and the radius of the filament tip orbit in air, but observed no precession, consistent with the absence of hydrodynamic interaction in air. Building on this, we present the next phase of this experiment: submerging the system in a high-viscosity fluid to introduce the hydrodynamic conditions necessary for precession. Our apparatus consists of a stepper motor driving a helical filament through a brass universal joint, with 3D-printed angle restrictors controlling the filament tilt angle between 0 and 40 degrees. Filament tip trajectories are recorded using a Basler camera and analyzed via particle tracking in TrackMate/ImageJ. Current efforts focus on characterizing filament behavior across tilt angles in air as a baseline before transitioning to viscous fluid, where we expect to observe torque-induced precession and enable direct comparison with theoretical predictions of spin and revolution angular velocities.
Home Institution: Case Western Reserve University
REU Faculty Advisor: Theresa Reineke
REU Mentor: John Hutchinson
Developing Polymeric Micelles for mRNA Delivery
Nucleic acid therapeutics, such as gene therapies and mRNA vaccines developed during the COVID-19 pandemic, have gained attention because of their potential to treat genetic disorders and cancer. However, nucleic acids require a delivery vehicle because nucleic acids can be degraded before reaching their target cells and cannot efficiently cross cell membranes on their own. Polymeric micelles can be used to protect and transport nucleic acids into target cells. In addition to protecting nucleic acids from degradation, polymeric micelles have tunable chemical properties that can be modified for optimal delivery.
This project focuses on developing a library of polymers that can be used in future machine learning studies to identify relationships between polymer composition and delivery performance. Starting with butyl acrylate, poly(n-butyl acrylate) (PnBA) is synthesized and then chain-extended with pentafluorophenyl acrylate (PFPA), which serves as a leaving group for further functionalization. Neutral and cationic moieties are added in at varying ratios to create statistical copolymers with differing charge distributions, resulting in polymers with different chemical properties. Cationic groups are important because they interact with negatively charged nucleic acids and influence delivery performance. On the other hand, neutral groups reduce toxicity by preventing the polymeric micelle from damaging the cell membranes of target cells. Nuclear magnetic resonance (NMR) spectroscopy is then used to characterize the synthesized polymers and determine the composition of the incorporated moieties.
The goal of this work is to generate a polymer library that can be used to study how polymer structure and composition affect nucleic acid delivery. In future studies, these polymers will be assembled into micelles and evaluated for their ability to deliver nucleic acids.
Home Institution: Lake Forest College
REU Faculty Advisor:Kade Head-Marsden
REU Mentor: Mikayla Fahrenbruch
Spin-Phonon Driven Decoherence of Molecular Qubits in an Open Quantum System
Molecular spin systems are promising candidates for quantum information science (QIS) due to their high tunability. A key feature for any qubit is its coherence, which is a measure of how long the spin state remains measurable. In the limit of low temperature, the rate of decoherence is dominated by a mechanism known as pure dephasing. At moderate temperatures, the mechanism of decoherence is more complex. An open quantum system framework is beneficial for modeling environmentally driven decoherence as it considers the interaction between the system and its environment. In particular, spin-phonon interactions are of interest as they contribute to transitions between spin states. The resulting population relaxation contributes to overall decoherence. Ab initio electronic structure methods are used to determine parameters in the Redfield master equation which is used to determine population relaxation dynamics. Previous derivations of these parameters involve a large number of complex calculations; however newer “single shot" methods can significantly save on computational cost. Investigating how spin-phonon interactions contribute to decoherence times will help to better design qubits that stay coherent in ambient temperatures.
Home Institution: University of Texas Rio Grande Valley
REU Faculty Advisor: Andreas Stein
REU Mentor: Bella McGrath
Development of Modified ZIF-8 Membranes for Improved
Carbon Dioxide Separation
Metal–organic frameworks (MOFs) are highly porous materials composed of metal ions and organic linkers that can selectively absorb and separate gases. In this project, a MOF-based membrane for improved CO₂ selectivity was developed using ZIF-8, a well-studied MOF known for its gas absorption and gas separation properties. The goal was to create a membrane capable of separating CO₂ more efficiently from gas mixtures. To enhance the separation performance of ZIF-8, three modification strategies were explored. First, a core–shell structure was synthesized by growing a thin layer of ZIF-8 on ZIF-L crystals, creating nanosheet-like particles with improved surface accessibility and shorter diffusion pathways. Second, post-synthetic ligand exchange was used to introduce amine functional groups that increase CO₂ interactions and improve CO₂ selectivity. Third, sodium dodecyl sulfate (SDS) was used as a surfactant template to generate a layered structure that could be exfoliated to produce thin MOF sheets. In this project, modified ZIF materials were dispersed onto a polymeric membrane that selectively captured CO₂. We aim to improve the materials by controlling particle morphology and by introducing chemical groups that interacted strongly with CO₂.
Home Institution:University of Texas at Rio Grande Valley
REU Faculty Advisor: Chris Ellison, Frank Bates
REU Mentor: Yukti Bharde
Processing Sulfonated Polyester/ PBT Polymer Blends for Interconnected Porosity
Porous polymers can promote selective permeability and high surface area which enable their use in biomedical, energy storage, and specialized filtration applications. In this project, immiscible blends forming cocontinuous morphology, defined as a state of blending with interpenetrating polymer phases, will be fabricated and analyzed. Porosity will be introduced in polymer blends through solvent extraction where the designated sacrificial phase is dissolved and the non-dissolved phase forms the final interconnected porous network. High temperature blending will be utilized to access different blending conditions that could lead to the formation of cocontinuous morphology. A microcompounder that applies high shear forces to finely combine the immiscible polymers will be used to blend sulfonated polyester and polybutylene terephthalate under constant nitrogen flow. Varying temperatures, screw rotation speeds and blending times will be explored. The blends will be extruded into a liquid nitrogen bath and collected for cryofracturing in order to promote a brittle fracture. With water as the main solvent, the sulfonated polyester acts as the soluble phase since it is water-dispersible and leaves the PBT matrix completely intact when submerged overnight at room temperature. With both the sulfonated polyester and PBT undergoing a transesterification reaction that is dependent on the blending conditions, a copolymer is formed at the boundary of the phases that helps compatibilize the immiscible blends. To validate whether the parameters of the blending led to the formation of cocontinuous morphology, the samples are coated in platinum through sputter coating. This will provide conductivity to the polymer blends for the SEM imaging of the topographic characteristics.
Home Institution: Normandale Community College
REU Faculty Advisor: Kevin Dorfman
REU Mentor: Lakshita Gopalani, Luyang Li
Simulating Self-Assembly of Linear and Bottlebrush Copolymers
Natural and synthetic polymers adopt a vast number of configurations to maximize their entropy. Our work examines linear block copolymers and bottlebrush block copolymers, of which contain a comblike layout. Molecular dynamics simulations of models allow us to capture the structure of these chains. When performing computational experiments, we can predict the behavior of macromolecules and their interactions. Using an open-source molecular dynamics package known as LAMMPS, we can simulate polymer trajectories and integrate this information to map their phase behavior. This data gives us insight into the self-assembly of copolymers. Harnessing the power of polymer topology proves itself greatly beneficial to modern material science. The production of this super soft material with large domain sizes allows for breakthroughs in areas such as photonics and separation.
Home Institution: Macalester College
REU Faculty Advisor: David Blank
REU Mentor: Becca Macgillvray
The Effects of Nanocrystal Composition on Organic Dye Adsorption
Dye-sensitized nanocrystal systems have uses in photovoltaics due to dye-to-nanocrystal electron transfer from the dye’s excited state. Previous research in the Blank Lab has investigated these systems using the dye (E)-2-cyano-3-[5-[4-(diethylamino)phenyl]thiophen-2-yl]-2-propenoic acid (1) bound to ZnO nanocrystal. They successfully bound dye 1 to the nanocrystal at approximately 100 molecules per nanocrystal. In2O3 and indium tin oxide (ITO) have better conductivity than ZnO, among other material properties, leading to their widespread use in optoelectronics such as thin film photovoltaics, making them an ideal candidate for investigation. Dye 1 has previously been shown to undergo quenching when bound to the nanocrystal, as electron transfer will outcompete emission. Fluorescence spectroscopy is used to assess the emission quenching in dye-nanocrystal systems. A competitive exchange Langmuir adsorption model is used to quantify the quenching. This is achieved by comparing dye 1’s emission with and without nanocrystals to determine the maximum surface coverage of dyes on the nanocrystal as well as the favorability of the binding process. Our research on dye-nanocrystal binding as well as future research regarding the kinetics of the electron transfer will guide the use of dye-sensitized In2O3/ITO systems and their usage in photovoltaics.
Home Institution: Utah State University
REU Faculty Advisor: Chris Leighton
REU Mentor: Hyunsol Son
Accelerating Topotactic Transformation Speed in Electrochemical Transistors
Electrolyte gating of perovskite oxides utilizes a small gate voltage to induce a strong interfacial electric field—an electric double layer (EDL)—that drives reversible ion migration and electrochemically modulates physical properties. This capability enables an energy-efficient route to novel spintronic, neuromorphic, and other electronic devices. Of particular interest is the electrochemically induced topotactic transformation between fully oxygenated perovskite (P) and oxygen-vacancy-ordered brownmillerite (BM) phases in electrolyte-gated perovskite cobaltite films (e.g. La1-xSrxCoO3-δ, LSCO), as well as the resulting changes in electronic, magnetic, thermal, and optical properties. However, there has been limited research on the operating speed of these transistors and methods for improving it. In LSCO films, the speed and reversibility of the transformation between the two phases are limited by the diffusion of oxygen vacancies (Dvo). While previous studies have investigated how the limits of transformation speed depend on gating geometry, film thickness, ion-gel thickness, and gate voltage [J. Liang et al., ACS Nano 2025 19 (30), 27782-27793], this study focuses on Fe substitution for Co in LSCO to improve the gating speed by increasing Dvo. We synthesize a La0.5Sr0.5Co0.8Fe0.2O3-δ (LSCFO) ceramic target to grow epitaxial perovskite LSCFO thin films on LaAlO3(001) substrates using high-pressure oxygen sputtering. Electrolyte gating will be performed at 300 K to determine the time required to achieve complete ON/OFF switching, EDL formation, and Vo diffusion. The LSCFO results will then be compared with those of a non-Fe-substituted La0.5Sr0.5CoO3-δ film to quantify the improvement in gating speed.
Home Institution:University of Delaware
REU Faculty Advisor: Michelle Calabrese
REU Mentor: Jackson Cleveland
Characterization of Glycolipid Self-Assembly in the Melt Phase
Disaccharide glycolipids are a type of biobased surfactant with a hydrophilic sugar headgroup and hydrophobic tail. These glycolipids can self-assemble into thermotropic double gyroid (DG) structures which are fascinating because DG structures have applications in drug delivery and filtration. However, DG structures typically occur over a narrow thermal window, and little is understood about how to improve thermal stability. To expand the thermal range where DG forms, we are exploring blends of glycolipids with different disaccharide headgroups, tail lengths, and anomeric stereochemistry, specifically alpha anomers which form a boomerang shape and beta anomers which form a flatter structure. We will use Polarized Optical Microscopy (POM) on blends composed of two glycolipids at varying mass percents to identify the melting point, DG thermal stability, and disorder temperature. We expect the birefringence patterns found using POM to be consistent with previous Small Angle X-Ray Scattering measurements. Furthermore, we predict to be able to tune DG thermal stability by changing the composition of the glycolipid blend. With data from both POM and SAXS, we expect to better understand the impact of hydrogen bonding and shape on glycolipid’s self-assembly into DG structures. Gaining a better understanding of how molecular changes in tail length, headgroup identity, and anomeric stereochemistry affect DG thermal stability will help identify blend compositions that increase DG stability and eventually guide the synthesis of new molecules with greater DG thermal stability.
Home Institution: Hamilton College
REU Faculty Advisor: Vivian Ferry
REU Mentor: Sri Aashrita Boddu
Investigating the effects of spacer layer thickness on chirality transfer from chiral Au nanoparticles
Chirality describes a symmetry property of a chemical or material in which its mirror image is nonsuperimposable upon itself. Due to this asymmetry, chiral materials interact differently with right versus left circularly polarized light, a response that can be quantified by circular dichroism (CD) spectroscopy. In some instances, a chiral material is able to induce its handedness and subsequent optical properties in an adjacent achiral material, a phenomenon known as chirality transfer. This ability to transfer chiroptical properties enables tunable control over the strength and range of the CD response. It can lead to broader applications in emerging technologies, such as displays, optical and quantum communications, and polarization imaging, where the ability to manipulate responses to circularly polarized light can be critical for device performance.
This study will investigate how chirality transfer varies as a function of the thickness of an achiral alumina spacer layer deposited on chiral nanoparticles via atomic layer deposition. Chiral gold nanoparticles will be deposited onto glass substrates using three different methods to determine the most efficient procedure for forming a monolayer. Techniques will include drop-casting, spin coating, and liquid-liquid self-assembly. UV-Vis and CD spectroscopy will be performed before and after the deposition of the spacer layer to quantify this relationship between optical properties and spacer layer thickness, while scanning electron microscopy will be used to capture images of the nanoparticles. It is hypothesized that spacer layer thickness will significantly shift and modify the measured circular dichroism.
Home Institution: Macalester College
REU Faculty Advisor: Mahesh Mahanthappa
REU Mentor: Giselle Campos, Mason Kozody
Modular Synthesis and Self-Assembly Behavior of Amide-Containing Dicarboxylate Gemini Surfactants
Surfactants, molecules comprising a hydrophilic head and hydrophobic tail, self-assemble into ordered lyotropic liquid crystals (LLCs) on the addition of water to make nanoporous materials for applications including drug delivery, catalysis, and ion transport. Network phases are of particular interest in these applications because of their interpenetrating aqueous and hydrophobic domains; however, single-tail ionic surfactants form such structures only in narrow composition windows since they cannot accommodate the necessary deviations from a constant mean curvature. Gemini surfactants, twin-head and twin-tail surfactants, exhibit wider network phase composition windows, yet their molecular structure/self-assembly relationships are underexplored. This work aims to synthesize dicarboxylate gemini surfactants with varied linker-to-tail length ratios by a modular ring-opening reaction of alkyl succinic anhydrides with alkyl diamines. The self-assembly behavior of these gemini surfactants in water will be characterized via polarized light microscopy and small-angle X-ray scattering to identify key molecular characteristics of gemini surfactants for the formation of stable network phases.
Home Institution: Cerritos Community College
REU Faculty Advisor: Chris Bartel
REU Mentor: Armand J. Lannerd
Machine Learning-Assisted Modeling of Oxygen Transport in Cobaltite Thin Films
Transition metal oxides are promising materials for energy and electronic applications because
their properties can be tuned through changes in oxygen content. In electrochemically active
oxides, the formation and annihilation of oxygen vacancies can alter electrical, magnetic, and
structural behavior, making oxygen mobility a critical factor governing device performance. This
project will focus on oxygen transport in the perovskite La 1-x Sr x CoO 3-δ (LSCO), a material
capable of accommodating varying oxygen concentrations and undergoing structural
transformations. Oxygen diffusivity can be studied using first-principles methods such as density
functional theory (DFT) and molecular dynamics simulations, which are based on quantum
mechanics. However, these approaches are computationally expensive, and difficult to apply
over the time scales needed to capture diffusion events. To address this challenge, this project
will utilize machine learning interatomic potentials (MLIPs), which can reproduce first-
principles predictions at a fraction of the computational cost. The primary goals of this work are
to develop workflows for generating defect structures, training and validating MLIP models, and
performing molecular dynamics simulations of oxygen transport in LSCO. These tools will then
be used to investigate how oxygen vacancy concentration, structural phase, and chemical doping
influence oxygen diffusivity. The broader goal is to improve our understanding of oxygen
transport in these oxides, and supporting the computational design of newer functional materials.
Home Institution: Caltech
REU Faculty Advisor: Jian-Ping Wang
REU Mentor: Zach Cresswell, Onri Jay Benally, Christian Brennan
Power Varied Depositions of Fe Doped Pt3Sn, a Weyl Semimetal, for Efficient SOT Switching
Spintronic devices are the future of next-generation computing, offering solutions to the volatility and power dissipation challenges in conventional CMOS architectures. While Magnetic Tunnel Junctions (MTJs) are foundational to non-volatile logic, conventional spin-transfer torque (STT) ferromagnetic MTJs require high write current densities that degrade the ultra-thin insulating barrier necessary to ensure quantum tunneling. Alternative spin-orbit torque (SOT) MTJ architectures utilizing heavy metals overcome barrier degradation, but they suffer from low energy efficiency and non-deterministic switching. To achieve higher energy efficiency, Dirac semimetals emerge as a promising topological material. In this work, we will investigate Pt3Sn, a known Dirac semimetal, doped with up to 21% Iron (Fe). The Fe is added to turn the Dirac semimetal into a Weyl semimetal by introducing magnetization without disrupting the crystalline structure. Five thin-film depositions will be prepared on MgO substrates via co-sputtering from Pt, PtSn4, and Fe targets at 350°C. While maintaining the Pt and PtSn4 target powers at 10W, the Fe target power will be varied from 10W to 40W in 10W increments to control doping concentration. Following fabrication, X-ray diffraction (XRD) will be used to verify the structure. Then, X-ray photoelectron spectroscopy (XPS) will be utilized to verify the elemental composition trend, and spin-torque ferromagnetic resonance (ST-FMR) will be performed to evaluate the spin Hall angle. We anticipate that the spin Hall angle will directly correlate with Fe concentration. This work will demonstrate a viable pathway to engineer highly efficient, spin-orbit torque (SOT) materials, ultimately eliminating the need for external biasing fields.
School: White Bear Lake High School
REU Faculty Advisor: Chris Ellison, Vivian Ferry
REU Mentor: Emily McGuiness
Title: Emily McGuinness
In my experience as an educator, today’s students are deeply engaged with the challenges facing modern society,
especially climate change. Major contributors to carbon emissions, often called the "grand challenges", include how we
generate electricity, manufacture materials, transport people/goods, produce food, and manage temperature. Science
students are expected to understand complex systems and develop the problem-solving skills needed to address them. These
challenges provide a framework for that learning. To explore the challenge of staying cool, we are developing a student
experiment to investigate: “Instead of cooling entire buildings, can we cool ourselves using textiles designed for passive
daytime radiative cooling (PDRC)?” PDRC textiles, such as nanoporous polyethylene, are being researched for their ability to
passively lower body temperature. Potentially, students will examine how material color/texture affects absorption and
emissivity by creating polylactic acid (PLA) films from transparent 3D printer filament and adding porogens (coarse/fine salt,
coarse/fine sugar, and polyvinyl alcohol), which will later be removed. Students will then measure optical and thermal
properties using a Vernier light sensor and an infrared thermometer.
Melrose Area High School
REU Faculty Advisor: Rene Boiteau
REU Mentor: Nicole Coffey, Anil Timilsina
Title: Why so Fe-w phytoplankton? A Storyline-Driven Oceanography Unit for High School Classrooms
The Southern Ocean is home to relatively few phytoplankton despite having high nitrate concentrations because
it is limited by iron availability. While this is a critical area of study as we seek solutions to climate change through carbon
sequestration, few curricular resources exist at the high school level to engage students in modern breakthroughs in
oceanography. In this comprehensive unit, students explore the ecological implications of iron fertilization, such as carbon
sequestration, population dynamics, and the cycling of matter, through inquiry-driven investigations of real-world
phenomena. Students follow protocol to conduct experiments discovering iron’s impact on Chlorella vulgaris population
growth and primary productivity, analyze global ocean data on nutrient and iron concentrations from the GEOTRACES
program to model nutrient cycling, and apply the Redfield Ratio to evaluate whether the Southern Ocean is capable of
sequestering the excess carbon dioxide produced from fossil fuel combustion each year. In doing this, students engage in
cutting-edge areas of study to critically evaluate real-world environmental engineering solutions to climate change while
mastering NGSS biology standards.
School: Spring Lake Park
REU Faculty Advisor: Vivian Ferry
REU Mentor:
Title:
School: North Branch High School
REU Faculty Advisor: Boya Xiong
REU Mentor: Sarah Ziemann
Title: Degradation of Plastics in a High School Classroom
Our work this summer was to create a curriculum about the degradation of plastics to bring to our high school
classrooms. This curriculum provides students with a hands-on opportunity to incorporate environmental science, chemistry,
and real-world consequences of plastic pollution. This lab engages students to test different degradation techniques such as
photoweathering, mechanical abrasion, and biochemical degradation. By analyzing the data, students will learn about the
chemical and physical properties of different types of plastics and how that can impact our environment. The lab involves
critical thinking, collaboration, environmental literacy, and scientific practices associated with the 2019 Minnesota Science
Standards. It also leads to the importance of sustainability and biodegradable plastic alternatives. Bringing this lab to the
classroom makes environmental chemistry relevant for our students and empowers them to become informed stewards of
our planet.
Funded by the National Science Foundation through the University of Minnesota MRSEC under Award Number DMR-2011401
UMN MRSEC
137D Amundson Hall, 421 Washington Ave. SE, Minneapolis, MN, 55455
P: 612-626-0713 | F: 612-626-7805