Home Institution: University of Texas Pan American
Major/Minor:
MRSEC Mentor: Dan Frisbie
Assembly of Monolayers on Silicon Through Diazonium Displacement
Much research has been focused on the use of organic conducting polymers as a way to able to obtain electronics the size of nanometers in the future. However, the science of electronics based on inorganic materials such as silicon cannot be ignored. One field of study is the idea of combining the existing semiconductor electronics with organic molecules aiming to result in a whole than is larger than the sum of its components. The coupling of the two compounds may eventually allow the properties of silicon to be improved in its performance in applications such as flexible electronics and solar cells. The central issue of this research is to synthesize organic monolayers on silicon surfaces and analyze how it will affect the properties of solid-state electronic devices. My goal for this REU is to come up with a novel synthetic route for covalently bonding cyano-polyphenylene vinylenes in a step-wise manner. By the end of this experiment, not only will the CN-PPV be on the surface, but it will also be able to be done one monomer after the other thereby allowing the length of the oligomer to be controlled.
Home Institution: University of Massachusetts Amherst
Major/Minor:
MRSEC Mentor: Lorraine Francis
Development of Cracks in Polymer latex coatings
Coatings are used to make and improve a lot of products such as laptops, medical devices and roofs. Polymer latex coatings are ideal because they are water not solvent base. In some cases it is necessary to add different additives such as coalescing aids which can be volatile organic compounds to reach a balance between film forming ability and mechanical properties. A mixture that contains 70% polyvinylidene and 30% acrylic is ideal for coating because it is environmentally friendly, has better mechanical properties and has better exterior weather ability. However, this mixture is prone to cracking due to tensile stress and capillary pressure that is developed during the drying process. The drying process of polymer latex consists of three stages: consolidation, compaction and coalescence. Temperature and the heat rate have an impact on the evaporation rate and thus the stress that leads to cracking. When the particle glass transition temperature is lower than ambient temperature a homogeneous film is formed. Our goal to find the critical thickness of coating to prevent the creation of cracks, by testing the effect of temperature, different types of substrate, and the heating rate on the stress developed in the coating. We plan to use silicon and polyethylene terephthalate as substrates. By adding different amounts of coalescence to the mixture we can study the effect on the critical thickness.
Home Institution: Winthrop University
Major/Minor: Biochemistry/Math
MRSEC Mentor: Ron Siegel
Nasal Delivery of Diazepam Prodrugs for the Treatment of Seizures
Every year, over 42,000 people suffer from prolonged seizures, also known as status epilepticus (SE). The usual approach to treating seizure emergencies is through an intravenous administration of anti-seizure medications in an emergency center. However, intravenous administration requires skilled personnel and transport to a medical facility. As a result, we want to develop an intranasal treatment that can easily be administered outside a medical facility. Benzodiazepines are widely used in the treatment of seizure emergencies. Compared to other benzodiazepines, diazepam (DZP) will be used as the drug of choice for intranasal treatment due to its high lipid solubility and a long elimination half-life. Previously, an intranasal formulation of DZP was developed where DZP was dissolved in glycofurol and then rapidly mixed with water. However, this drug was no longer developed due to the pain associated with the formulation.
Our goal is to develop a pro-drug of DZP that will be highly soluble in water. Phosphate salts will be used to convert the lipophilic drug into hydrophilic derivatives. Ideally, the highly water-soluble DZP pro-drug can be dissolved in a small amount of saline (>5mg/100 μL) and then applied to the nasal mucosa, where phosphatases will release the drug. To accelerate the release of DZP from the pro-drug, we also want to investigate the co-administration of phosphatase enzymes.
Home Institution: University of Nebraska, Lincoln
Major/Minor: Chemical and Biochemical Engineering
MRSEC Mentor: Steve Koester
Surface Modification of Graphene
Graphene is a promising candidate material for nanoelectronic devices because of its monolayer thickness, high carrier mobility, thermal conductivity, and mechanical strength. However, to date, a significant shortcoming of graphene is its inability to be chemically doped, which is a necessary property to realize practical devices. In this work, we will investigate the use of various surface treatments to modify the electrical properties of graphene. Dopant molecules will be spin-coated or thermally adsorbed onto graphene surfaces and characterized via AFM and Raman spectroscopy. The modified graphene substrates will be incorporated into devices and the effect of the surface treatments on their current-voltage characteristics will be determined. Finally, we will study the ability to selectively treat the graphene surface in lithographically patterned structures. This work will be an important step in evaluating the suitability of graphene for future electronic device applications.
Home Institution: Swarthmore
Major/Minor: Electrical Engineering
MRSEC Mentor: Lee Penn
Microwave Assisted Solvothermal Synthesis of Copper Sulfide Nanoparticles
Copper sulfide nanoparticles exhibit characteristics attractive for photovoltaics. They have a direct band gap of 1.2eV, are made from cheap, abundant, and benign materials. Our goal is to develop synthesis methods, characterize, and isolate the phases of copper sulfide produced in various microwave-assisted solvothermal syntheses. We will examine how synthesis parameters such temperature, pressure, power, time and precursor concentrations affect the size, morphology, and phase of synthesized nanoparticles. The results will be characterized using X-ray diffraction, TEM and UV-Vis spectroscopy.
Home Institution: University of Wisconsin, Eau Claire
Major/Minor: Physics and Engineering
MRSEC Mentor: Beth Stadler
Galfenol Nanowires for Touch Sensors and Electroplated Thin Films
This project worked with a new material called Galfenol (FeGa). Bilayer templates made of a gold base and an anodized aluminium oxide (AAO) upper layer with hollow tubes were used to grow segmented nanowires within the tubes. The AAO layer of the templates was later chemically dissolved leaving the nanowires exposed, but still connected to the gold base layer. The segments of the nanowires were made of Galfenol and Copper. When Galfenol is compressed, the direction of magnetization changes in response to the deformation. By segmenting the nanowires, the direction of magnetization changes more dramatically and is therefore easier to detect. Synthesis of CoGa and NiGa and the basic properties of each were also observed and tested.
Home Institution: Amherst College
Major/Minor: Chemistry and History
MRSEC Mentor: Marc Hillmyer
Graft Polymerization of polylactide onto a polyisoprene backbone
With the current push toward ecologically conscious goods and future oil shortages drawing near, the need for renewable consumer resources is an ever-pressing issue. Polylactide, a renewable and biodegradable polymer, is currently employed in medical and packaging industries, though its uses are limited because of its low glass transition temperature and brittleness. However, when polylactide is blended with stronger, more durable polymers, the new material formed exhibits favorable characteristics. It is hypothesized that by blending polylactide and polyisoprene, another potentially renewable polymer, we can make a more commercially useful and ecofriendly plastic. This will be done through the exploration of the creation of a graft copolymer with a polyisoprene backbone and polylactide graft branches. Interestingly, by manipulating the ratio of polylactide to polyisoprene in the copolymer, a range of material properties can be sampled. We expect to see both thermoplastic and tough behaviors and plan to explore these properties through mechanical testing.
Home Institution: University of Minnesota
Major/Minor: Chemical Engineering/Chemistry
MRSEC Mentor: Tim Lodge
Phase behaviors of Poly(Ethylene-Oxide) in Ionic Liquids
We examine lower critical solution temperature (LCST) phase‐behavior of poly(ethylene oxide) (PEO) with low molecular weights (Mw = 2000 and 3,400); dissolved in ionic liquid (IL),1‐ethly‐3‐methlyimidazolium tetrafluoroborate ([EMIM][BF4]). Phase transition is determined using cloud point measurements. In similar experiments with higher molecular weight PEO (Mw = 5000 and 20,000), liquid‐liquid phase separation occurred from 130‐170 °C. For the lower Mw PEO, we expect to obtain phase separation at higher temperatures than that of higher Mw PEO.
Home Institution: Anoka Ramsey Community College
Major/Minor: Electrical Engineering/Math
MRSEC Mentor: Paul Crowell
Spectroscopy of spontaneous spin noise
Spin is the magnetic moment of a particle. For example, elementary particles such as the electron possess spin angular momentum even though they are point particles. “Spin resonance” occurs when a radiofrequency field is used to drive the precession of spin about a static magnetic field. This is similar to the driven harmonic oscillator except that the resonant frequency is determined by the gyromagnetic ratio of the particle and the magnetic field instead of the mass and spring constant. In an ordinary resonance experiment, the response is measured as amplitude of motion as a function as a driven frequency. The unique aspect of my experiment is that instead of driving the resonance, I will probe the system by “listening” to noise in thermal equilibrium. The spins will be detected through their effect on the polarization of light passing through a tube filled with Rb vapor. I will develop a technique to do this using a relatively inexpensive diode laser and data acquisition card. The spin noise will be detected as fluctuations in the polarization of the light. The goals for this project are to be able to measure spin resonance of each isotope of Rb, perform spectroscopy in a magnetic field, and to be able to adapt this technique for the measurement of spin resonance in a semiconductor device.
Home Institution: University of Nebraska, Lincoln
Major/Minor: Chemical Engineering
MRSEC Mentor: Eray Aydil
In situ synthesis of Cu2ZnSnS4 thin films for solar cell applications
Cu2ZnSnS4 (CZTS) is a promising candidate material for the absorber matrix of solar cells offering high scalability due to its low toxicity, low cost, and the abundance of its constituent elements in the earth’s crust. In addition, CZTS has a bandgap of 1.45eV, which is ideal for capturing solar radiation. CZTS will be synthesized in situ by annealing a solution of copper, tin, and zinc dithiocarbamate complexes. Specifically, stoichiometric amounts of the desired metal dithiocarbamate complexes will be dissolved in chloroform and the resulting solution drop-coated onto a molybdenum-coated glass substrate. The metal complex solution will be heated and annealed at temperatures between 300 and 600°C to form a thin film of CZTS. The effect of various annealing parameters, such as temperature, ramp rate, and gas composition, on the growth of CZTS thin films will be explored. The CZTS samples will be characterized using Raman spectroscopy to confirm the formation of the kesterite crystal structure.
Home Institution: University of Texas Pan American
Major/Minor: Mechanical Engineering
MRSEC Mentor: Tim Lodge
Rheological Behavior of Poly(styrene-b-ethylene-alt-propylene) Diblock Copolymer Micelles in Squalane
Block copolymers have the ability of forming micelles that can self-assemble given a specific solvent. The formation of micelles was observed when dissolving the diblock copolymer Poly(styrene-b-ethylene-alt-propylene) also referred to as SEP(17-73) in Squalane. The SEP(17-73) micelles consist of a hydrophobic core surrounded by a hydrophilic shell. The micelles tend to follow a Body Centered Cubic (BCC) lattice arrangement given the proper temperature conditions. This arrangement is considered as an ordered state and the material behaves in an elastic manner. When increasing the temperature the micelles disassemble into a disordered formation exhibiting a viscous behavior. Rheological measurements using a parallel-plate separated actuator and detector rheometer are conducted in the viscous-elastic region in order to determine the order-disorder transition (ODT) temperature for different concentrations of SEP(17-73) in Squalane.
Home Institution: Minneapolis Community and Technical College
Major/Minor: Biomedical Engineering/History of Medicine
MRSEC Mentor: Kevin Dorfman
The Kinetics of DNA Electrophoresis Using Nanoporous Structures Contained Within Microfluidic Channels
An incredibly compelling topic of Bio and Biochemical Engineering as of late is the construction and usage of microfluidic biochips. The various systems that employ microfluidic technology serve to enhance the precision and efficiency of chemical and biochemical assessment, cell growth cultures, electrophoresis, as well as various analytical processes. Needless to say, accurate and proven theoretical models are essential to catalyze the further progression of this field. As such, these models are greatly desired and highly sought after. The project we have chosen to embark upon entails the use of soft lithographic techniques to create a shifted-T microfluidic channel. Evaporation assisted self-assembly is used to grow periodic, 900nm silica colloid crystals. From this crystal, a well-ordered inverse-opal nanoporous structure can be created through thorough saturation of photoresist and subsequent strategic photo-masking. The resultant nanoporous structure can then be used to cleave DNA through electrophoretic experimentation. We postulate that the architecture of the structure is such that the kinetics the forward as well as—upon the inversion of charge—reverse mobility of the DNA can be delineated and offered as support of the currently proposed functional models.
Home Institution: Clemson
Major/Minor: Ceramics and Materials Engineering/Chemistry
MRSEC Mentor: Andre Mkhoyan
TEM/STEM simulations of BN and MoS2 nanotubes
Boron nitrate (BN) and molybdenum disulfide (MoS2) nanotubes are currently being studied for their potential as semiconductors in electronic devices as well as their ability to withstand much larger amounts of heat compared to similar carbon nanotubes. BN and MoS2 nanotubes can be studied using transmission electron microscopy (TEM). TEM uses a beam of electrons to create images with much higher magnification than what is possible with an optical microscope. This magnification allows the viewer to see atomic level projections of solid samples. Using a program to theoretically simulate TEM, BN and MoS2 nanotubes will be examined for armchair and zigzag structural defects using bright field and dark field images with conventional and scanning TEM methods. Once defects are located within the nanotubes, the imaging conditions will be altered until they are optimized. Knowing the optimal microscope conditions for detecting defects in these nanotube structures will be useful in future experimental TEM studies.
Home Institution: University of Texas Pan American
Major/Minor: Mechanical Engineering
MRSEC Mentor: Dan Frisbie
Kelvin Probe Force Microscopy of Organic Semiconductor Layers
The morphology of thin film organic semiconductor layers at various insulating and conducting interfaces determines the extent of inter- and intramolecular overlap, which in turn determines the electrical properties of operating organic thin film devices, such as organic field effect transistors (OFET) such as Pentacene -Silicon dioxide ultra-thin films. Structural information with Atomic Force Microscopy (AFM) and electrostatic information from Kelvin Force Microscopy (KFM) can be used as complimentary techniques to probe the structural and electrostatic complexity of the organic layers. AFM is a form of high resolution scanning probe microscopy (SPM), wherein a nanometer-scale probe is sensitive to forces at the sample surface whether from height or electrostatic variation. KFM is a non-contact surface sensitive technique that maps out the surface potential variation within organic thin films. The surface potential distribution of these films, which is directly related to the packing structure and electronic states of the organic molecules, greatly affects the charge transport. With Providing clear structure / property relationships for organic semiconductors by AFM and KFM we can essentially explain the nature of charge transport mechanisms and their inherent electrostatic bottlenecks within the active layers.
Home Institution: Florida A&M
MRSEC Mentor: Efie Kokkoli
Improved Delivery Of Therapeutic Drugs to α5β1 Integrin Expressing Cell Line
Recently, there has been research designed to improve drug delivery systems to targeted cancer cells. The main goal of this project is to deliver therapeutic drugs to the α5β1 integrin expressing mcf-7 (breast cancer) cell line. This is to be done via poly(ethylene glycol) (PEG) containing liposomes, which will carry the encapsulated drugs, target the α5β1 subunits of the tumor cells, and release the drugs into the cells. Fibronectin-mimetic peptides attached to the liposomes are ligands for the α5β1 subunits and are responsible for targeting the appropriate cells. Since liposomes have a hydrophobic exterior and hydrophilic interior, the hydrophobic drugs being used easily become encapsulated within the hydrophobic bilayer of the liposome. This poses a few problems as the drug might be released, by leakage or other means, before reaching its destination and for this reason, our aim is to synthesize a liposome in which the drug is encapsulated securely in the (hydrophilic) center until it reaches its target cancer cells.
Home Institution: College of Menominee Nation
MRSEC Mentor: Chris Leighton
Design and implementation of a high temperature resistivity measuring apparatus
My summer research will be to design a high temperature probe which can measure the resistivity of certain metals as a function of temperature in a commercial superconducting magnet system. To do these measurements we must first fabricate a mechanism for mounting and electrically contacting our samples in a high temperature probe. The design and fabrication of such a system will be my first primary focus of my summer work. There are two difficulties in measuring at high temperatures. First is mounting the sample, and the second is keeping constant contact of our electrical system to the sample itself. Since numerous physical phenomena occur at high temperatures the design and construction of our probe will be highly valuable to us. Our proposal will be a spring loaded pin system for easy mounting and a specially designed ending to our probe for constant pressure, and contact with our sample. Although our insert is specifically employed for magnetotransport measurements, it is clear that similar designs could be used for all manner of electrical, magnetic, and thermodynamic measurements.
Home Institution: College of Menominee Nation
MRSEC Mentor: Victor Barocas
Strain Tracking Using Polydimethysiloxane (PDMS) Cruciforms
My summer research consists of observing the Posterior Vena Cava, which is one of the major veins in a pig. Our goal is to look closely at the point where the posterior vena cava branches into the two smaller veins. We want to know the difference in the mechanical properties and structural properties of that point. But as of right now, we are currently examining a decellularized rat heart. We cut it into two sections; the left ventricle and the right ventricle. We cut out a criss-cross shaped sample from each ventricle. We then place our sample into a machine known as a Biaxial Machine, which consists of four arms pulling at the sample in four different directions. During this process, we record it to a computer which allows us to study the stretching of the sample. We use this data to learn about the properties and elasticity of the fibers in the heart.
Home Institution: Grambling
MRSEC Mentor: Kevin Dorfman
DNA Tethering to an Ultra-hydrophobic Surface
Inspired by the Lotus leaf’s self-cleaning surface, super-hydrophobic surfaces contain hydrophobic micron-size features. When contact with liquid, a shear-free gas-liquid interface can be formed between the surface features. The slip velocity has been measured at the shear-free interface and proved as the mechanism of the super-hydrophobic surface’s mixing enhancement effect. Complex small scale helical flows were predicted by numerical model, but traditional micro-PIV measurement could not visualize such flow structures. In this project, a cross-layered, ultra-hydrophobic polydimethylsiloxane chip was created with diagonal and horizontal micro-channels in efforts to mimic the hydrophobic and multilayered morphology of nanoscaled roughness of the Lotus leaf. Our research aims to tether DNA to the ultra-hydrophobic micro-channels to closer examine the laminar flow. It is our deduction that the small scale helical flow near the super-hydrophobic surface will be able to be visualized by the movements of tethered DNA. We presume the applications in both the research and commercial domain will be substantially increased in fully understanding and visualizing the microfluidic flow.
Home Institution: University of Texas Pan American
MRSEC Mentor: Andreas Stein
Synthesis and Characterization of Three-Dimensionally Ordered Macroporous (3DOM) Materials
In the past decade, the synthesis of nanoporous materials with controlled porosity on various length scales has emerged as an important field in materials science. Among different types of materials with controlled pore architectures, mesoporous solids, prepared by surfactant templating, and three-dimensionally ordered macroporous (3DOM) materials or inverse opals, prepared by colloidal crystal templating, have been widely investigated because of their potential applications in absorption, separation, catalysis, photonic crystals, power sources, sensors, porous electrodes, and energy storage. Our goal is to synthesize 3DOM materials, such as carbon and silica, with hierarchical pore structures and to characterize their distinctive structural features, which include both the internal architecture of 3DOM materials and their external morphology. These 3DOM materials possess both meso- and macropores. Mesopores, ca. 3 nm in diameter are obtained by adding block-copolymer chains (e.g. F127, a nonionic surfactant) to the precursor mixtures. Macropores, ca. 300 nm in diameter are produced by infiltrating a periodic array of uniform polymer spheres (e.g. poly(methyl methacrylate)) with a precursor. With the increased development of synthesis techniques for engineering of 3DOM materials, their pore sizes, surface areas, pore volumes, and skeletal geometries will be easily tailored by controlling the synthesis conditions. The basic synthetic methodology employs infiltration, polymerization, vacuum drying, centrifugation, and carbonization. Analyses of 3DOM materials will include XRD, thermal analysis, porosity analysis, SEM and TEM.
Home Institution: Bridges ALC
MRSEC Mentor: Eray Aydil
Alternative Solar Cells - for High School Students
High School students have a limited understanding of the concepts and process involving energy conversions using solar cells. Additionally, there is a rudimentary understanding of the limitations regarding the science behind the current technology. My work helps to address these issues for better success an understanding of high school students.
Home Institution: Chicago Hope Academy
MRSEC Mentor: Chun Wang
Comparing Cell Uptake with Fluorescent Polymers
Different cell types take up foreign particles with different ability and frequency. In the Biomedical Engineering labs at the University of Minnesota, research is currently underway to compare the uptake of polymers for delivery of DNA vaccines in different cell types. In this lab, students will analyze cell transport in two types of cells lines: Immune cells (Dendritic) and Human Tumor cells (Glimoal). Students will visualize the uptake with fluorosphere polymers of different sizes. The fluorospheres will then be analyzed and photographed using a fluorescent microscope.
Home Institution: Robbinsdale Cooper
MRSEC Mentor: E.D. Dahlberg
Quantitative Measurement of Diamagnetism and Paramagnetism of H2O, NaCl, and CuSO4
We sought to develop a quantitative demonstration of the diamagnetic property of H2O that could be easily conducted in a high school classroom with a minimum of available materials and mathematical knowledge. Additionally, we investigated the effects of a magnetic field on H2O solutions containing NaCl and CuSO4. By mapping the deflection of an incident laser, we were able to determine both the size and shape of the deformation on the surface of the solution. Our findings strongly suggest that the change in gravitational energy density for each solution is due entirely to the effect of the magnetic field.
Home Institution: Veterans Memorial HS , UTPA
MRSEC Mentor: Uwe Kortshagen
Quantom Dots
Introducing Nano crystal technology and its application to high school students through studying the effect of light emission that quantum dots produce based on their different nano scale size.
Home Institution: Minneapolis Edison
MRSEC Mentor: Kevin Dorfman
Engineering for the New Standards
Like other states, Minnesota is incorporating engineering into the state science standards. This is a big step forward for STEM. Unfortunately, many K-12 educators feel ill-equipped to teach these standards because they have never had experience in any of the engineering disciplines, and, until recently, engineering has not been part of teacher prepartation. Also, much of the emphasis in engineering in the K-12 setting has focused on robotics (suitable for high school physics courses). The author has developed lessons that can be used by teachers to address the engineering standards through both chemistry and life science courses offered in high schools, allowing for more flexibilty in meeting the engineering standards.
Home Institution: Convent of the Visitation School
MRSEC Mentor: Lorraine Francis
Cool Roof Coatings in the Classroom
I've designed an adaptable curriculum unit that uses cutting-edge research in cool roof coatings to meet new engineering-oriented Minnesota Academic Standards in Science. In this unit, students learn about materials scientists and environmental engineers, research background information and motivations for cool roof coatings, design and test their own coating formulation using engineering principles, and participate in a poster session to share and discuss their results.
Home Institution: Anoka Hennepin ISD 11
MRSEC Mentor: Claudia Schmidt-Dannert
Modeling Transformation of E. coli
The purpose of this unit is to use modeling as a tactile teaching method for the transformation of E. coli. The unit uses modeling versus the commercially available lab kits so that more students can be exposed to this content. The materials are simple (beads, pipe cleaners, etc) and low cost. Students will construct a model of an E. coli bacterium and then transform it to show the insertion of a green fluorescent protein (GFP) into the bacteria’s plasmid. This unit can be used while teaching about Griffith’s pneumonia transformation or added into a unit discussing biotechnology.
Funded by the National Science Foundation through the University of Minnesota MRSEC under Award Number DMR-1420013
UMN MRSEC
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