Journal of Undergraduate Materials Research
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- The Effect of Viscosity and Ion Size on the Transduction of Ionic Polymer Metal Composite ActuatorsCopley, Lisa; Hubbard, Elizabeth; Maisano, Adam (Virginia Tech Department of Materials Science and Engineering, 2005-09-22)Ionic polymer membranes plated with platinum and gold serve as actuators when a small potential is applied. However, the water used to hydrate the membrane evaporates during use, decreasing actuator performance. Ionic liquids are being considered as a replacement for water because of their low vapor pressure. Prior studies show that the large ion size and high viscosity of ionic liquids slow the response time of the polymer membrane when a voltage is applied. This study examines the relationships of ion size and viscosity to transduction by modeling ionic liquids with inexpensive salts of varying ion size and glycerol/water solutions. Based on these results several ionic liquids were selected and tested for use as membrane sol vents. This study includes frequency response, step response, and impedance tests of samples impregnated with Li+, K+, Cs+, TMA+, TEA+, and TBA+. Actuators solvated in solutions with a viscosity similar to 70–80 wt. % glycerol solutions (18–46 cP) and cation size similar to that of TMA+ (0.347 nm) appear to yield the best results. When used as the membrane solvent, the ionic liquid 1-ethyl-3-methyl imidazolium trifluoromethanesulfonate (IL #3) resulted in the greatest strain per charge per area of the three ionic liquids tested in this study.
- Small Size Fluidic Devices by Freeform ManufacturingFolger, Luis (Virginia Tech Department of Materials Science and Engineering, 2005-09-22)The objective of this study was to innovatively use Freeform Manufacturing, specifically Selective Laser Sintering (SLS) to fabricate rapid prototypes of small size fluidic devices. The polymer used by the SLS application is very porous and presents a rough final surface. Material analyses were performed using Scanning Electron Microscopy (SEM), optical microscopy and Rockwell P hardness tests to develop methods for physical property enhancements. The study showed the feasibility of manufacturing a functional miniature size, e.g. sub-centimeter size, in-line static mixer derived from available macro-scale models using SLS and an additional coating process. It was determined that some of the variable parameters of the SLS process affected the mechanical and physical properties of sintered specimens. Related issues can be enhanced by sintering at relatively high laser power settings and post-processing the prototype with a polymer based coating.
- A Novel Porous Polymers Manufacturing TechniqueHartsell, Erica (Virginia Tech Department of Materials Science and Engineering, 2005-09-22)There are many applications of porous materials, including the polymer, water, and metal filtration units of various industries; catalytic substrates; fuel cell components; surgical masks for doctors; “gortex” gloves for skiers; etc. In this paper, we discuss a novel method to make porous polymers. This method utilizes a mixture containing a biological agent (such as fungi) and a polymer. Characterization of the samples using the optical microscope and the scanning electron microscope (SEM) will also be discussed.
- Journal of Undergraduate Materials Research, Vol. 5 (2015)(Virginia Tech Department of Materials Science and Engineering, 2015-01-01)The Journal of Undergraduate Materials Research (JUMR) is a student-run scientific journal dedicated to research performed by students in materials science and related fields. The primary goal of this journal is to provide a platform for undergraduate researchers to publish their work. The secondary goal of this journal is to provide opportunities for undergraduates to practice their communication skills and gain experience working with reviewed publications. The editorial staff for the fifth issue of the Journal of Undergraduate Materials Research is comprised of an interdisciplinary team of students and faculty from departments including Architecture, English, Business, and Engineering. This issue features articles and student research of subjects in Materials Science and Engineering, Biomedical Engineering, and Chemistry. The works within this issue represent students from Virginia Tech, the Massachusetts Institute of Technology, and the University of Kentucky.
- Processing and Characterization Techniques for a Mica Filled Polymer CompositeWhipkey, Sarah; Roman, Chance; Seay, Kevin (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)Mica particulates (filler) were combined with polymethyl methacrylate (matrix) to form a polymer matrix ceramic composite (PMCC). Mica concentrations in the range of 10-80 wt% mica with particulate sizes in the range of 53-212 μm were used. Dynamic mechanical analysis was used to conduct stress/strain tests on these composites in order to observe the resulting elastic moduli with varying mica particulate size and concentration. The elastic moduli showed an overall increase with increasing mica concentration in all but one tested particulate size, which exhibited a peak modulus at 60 wt% mica filler. Statistical analysis showed that both the mica concentration and mica particulate sizes were significant to the resulting elastic moduli, as well as the interaction between these two factors. Optical microscopy was used to observe the interface between the polymer matrix and mica particulates in order to determine the degree to which the two materials bonded to each other. It was observed that the PMMA and mica showed good bonding, meaning the formed materials were successfully combined into a cohesive composite.
- Mechanical Behavior of Nafion and BPSH MembranesKyriakides, Steven (Virginia Tech Department of Materials Science and Engineering, 2005-09-22)A brief characterization of the mechanical behavior of Nafion® 117 and BPSH-35 membranes took place through uniaxial loading, stress relaxation, and creep compliance tests. Membranes were subjected to uniaxial loading at various strain rates to observe yield and fracture behavior. Stress relaxation tests measured relaxation response to strain rate and relaxation strain. Creep compliance tests led to the formation of a creep master curve for the Nafion® membrane. Tests showed that for Nafion®, higher strain rates produced higher yield stresses and yield strains as well as faster initial relaxation. Strain rate had no effect on strain at fracture. Higher re laxation strains also led to faster initial stress relaxation in both Nafion® and BPSH. BPSH results showed no yield trends in uniaxial loading, though they illustrated lower breaking strains with higher strain rates.
- Exploration of Shape Memory Polymer for Automotive Coating ApplicationsWang, Ming (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)Shape memory polymer (SMP) is one special kind of polymer which can recover back to permanent shape after being mechanically deformed. As for automotive coating, most of the defects occurs on the clear coat layer, if it can be replaced by shape memory polymer, the defects can be easily removed due to the self-healing ability of shape memory polymer. In this experiment, the self-healing ability of epoxy based shape memory polymer thin lm (around 100μm) is examined. Five indents on the thin lm shape memory polymer with depths from 4.9μm to 5.5μm are all disappeared after 15 minutes heating at 70oC. The average hardness of the polymer is 165 ± 2MPa and the modulus is 5.76 ± 0.02GPa (assume Possion’s ratio 0.4).
- Chitosan: An Antimicrobial PolymerVenkatraman, Priya (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)Antibiotic resistant infections are a rising problem in the United States and globally. These infections are listed as a top concern by the Center for Disease Control and Prevention (CDC) as well as by the World Health Organization. Antibiotic resistance is a phenomenon where microorganisms acquire or innately possess resistance to antimicrobial agents. Antibiotic resistant infections significantly reduce the effectiveness of the treatment causing patients to remain infectious longer and increasing the risk of spreading the resistant microorganisms. Antibiotic resistant infections are incredibly detrimental to society and are threatening many of the medical advances made in the past century.
- Biomorphic Materials: Silicon Carbide Derived from Natural Carbon PrecursorsSurbey, Wyatt (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)The recent initiative to cater toward an environmentally efficient lifestyle has put pressure on many industries and practices. However, the success of these green initiatives has not been an easy achievement. During the past decade, scientists and engineers have worked tirelessly to discover a more natural way to process Silicon Carbide (SiC). A new category of materials, called biomorphic materials, has provided insight into how materials can be synthesized from bio-organic materials while retaining similar properties and performance. In comparing SiC with its biomorphic cousin, BioSiC, there are notable similarities and differences in the properties, structure, processing, performance, and environmental concerns between each material discussed in this article.
- Bacterial Cellulose as a Potential Bone GraftLowman, Kennedi (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)Each year tissue engineering costs the United States $2 million dollars. Bacterial Cellulose (BC), a hydrogel with a fine fiber network, is produced by the bacterium Acetobacter xylinum that can be used as a protective coating. In contrast to other polymers, BC possesses high tensile strength, high water holding capabilities, and high mechanical properties. The purpose of the current study is to determine if individual fibers of BC can be functionalized with calcium by applying an electric field. BC was grown and calcium was deposited simultaneously using Corn Steep Liquor (CSL) media, with the addition of fructose, in channels 4 cm long x 5 mm wide x 2.5 mm deep. The channels contained platinum electrodes supplying an electric field of 3 to 7.5 volts for 72 hours in the presence of CaCl2. BC pellicles formed and were then examined using the Environmental Scanning Electron Microscope (ESEM). Energy-Dispersive X-ray Spectroscopy (EDS) was also used to determine the composition in each sample. Calcium was found deposited on the BC fibers at 5.5 volts. Lower voltages, such as 4.0 volts, resulted in no calcium deposition on the fibers. The presence of Carboxymethyl Cellulose (CMC) is critical for the calcium deposition. Calcium deposition will occur at 5.5 volts suggesting there may be a specific electric field requirement for calcium deposition on BC.
- VTFire: Casting the FutureMerritt, Geoffrey (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)Concealed in the depths of Plantation Drive, at the end of a long country road lined with cattle and farmland scenery from the Virginia Tech agricultural department lies Virginia Tech’s Foundry Institute for Research and Education (VT FIRE). VT FIRE is a relatively new program at Virginia Tech having been established in the spring of 2011, it aims to teach students the fundamentals of foundry operation, equipment, and safety as well as the art of metallurgical design. In the past 4 years, VT FIRE has grown and prospered immensely due to the continued interest of college students in areas such as metal casting and alloying as well as the experience of Dr. Alan Druschitz. For four and a half years, Dr. Druschitz has continued to accomplish more growth, and attract new students, developing an entire metal castings minor around the extensive list of courses the foundry has to offer. Dr. Druschitz, in addition to earning a Ph.D. in metallurgical engineering, has had prior real world experience in industry. This benefits the students by having the opportunity to learn how to operate the various types of foundry equipment safely and effectively, a proficiency that could prove valuable in many future careers.
- Synthesis and Toxicity of Lipid-Coated-Titanium Oxide NanoparticlesHollingsworth, Louis; Conduff, Joseph; Balzer, Conner; Tran, Sieu; Hamid, Waqas; Rakes, Lauren (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)Nanoparticles have a broad range of applications in novel materials and consumer products. Due to the unique properties of nanoscale materials, the toxic effects of various nanoparticles are largely unknown. Surface modifications to nanoparticles, such as membrane or lipid coatings, may reduce immunogenicity and environmental toxicity, but these effects remain largely uncharacterized. The synthesis of lipid-coated titanium oxide nanoparticles was optimized and toxicity was evaluated. Thermogravimetric analysis showed that 5 μM of tricarboxylic amphiphile sufficiently generated uniformly coated nanoparticles. Toxicity studies on Zea mays (corn) revealed that uncoated titanium oxide nanoparticles exhibited phytotoxicity, while lipid-coated nanoparticles had effects resembling deionized water. Scanning electron microscopy displayed visual evidence of nanoparticle absorption into the corn seedlings in experimental groups.
- Domain Wall Collision-Induced Spin WavesDelaney, Tristain (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)A series of micromagnetic simulations are conducted whereby two transverse domain walls are injected into a straight magnetic nanowire under an applied field. It is found that, based on the relative orientation of the domain walls, the two may annihilate, resulting in the generation of an intense spin-wave burst. Since the applied magnetic fields for these simulations are smaller than the Walker breakdown field, these results present an extremely low-energy means of generating and controlling spin waves for engineering applications.
- Magnesium-PMMA Composites Formed by Mechanical AlloyingHiser, Matthew (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)The mechanical alloying process is used to form poly methyl methacrylate (PMMA)-5 vol.% magnesium (Mg) composites by high-energy ball milling the blends for up to 10 hours. The milling products and their compacted composites are characterized and compared with milled pure PMMA. Mechanical alloying can cause degradation of the amorphous thermoplastic polymer in the powder mixture but also allows for increasingly fine dispersion of Mg in the PMMA matrix with milling. X-ray diffraction (XRD) and image analysis of optical micrographs show that the magnesium remains crystalline, and its particle size reduces with milling time from an average of 200 microns to under 10 microns after 10 hours milling. Additionally, peak broadening from XRD analysis shows decreasing crystallite size within the particles. The hardness of the composite increases with milling time by up to 7%, whereas the hardness of the milled pure PMMA decreases with milling time by about 5%.
- Aerogel Fabrics in Advanced Space Suit ApplicationsCrowell, Cameron; Reynolds, Cameron; Stutts, Andrew; Taylor, Hunter (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)New insulating materials for spacesuits will need to be able to function well in low-pressure and gaseous environments, such as the Martian atmosphere. In order to address this need, Orbital Outfitters, a small spacesuit company, is currently investigating new materials for the insulating layer of the space suit. One such material is an aerogel fabric composite, promising because of its flexibility and low thermal conductivity. The purpose of this study is to characterize the effect stitching an outer layer has on the stiffness, strength, and thermal conductivity of two types of aerogel fabric, ThermalWrap and Pyrogel 2250. Tension tests were used to investigate the mechanical properties, while two different methods were used to evaluate the thermal conductivity of the materials. Results showed a dramatic increase of thermal conductivity when an outer material was stitched directly to the aerogel fabric, while two other geometries showed a decrease in thermal conductivity. Tension tests revealed that stitching increased the strength of the ThermalWrap. Overall, it was determined that stitching the material was not a viable option due to the increase in thermal conductivity and difficult manufacturing. The two other geometries tested proved much more effective, as they were easier to manufacture and showed a decrease in thermal conductivity.
- Strength and Microscopy Analysis of Surface-modified Soda-lime-silicate Glass RodsBumbaco, Amy; Young, Jacob; Zachar, Michael (Virginia Tech Department of Materials Science and Engineering, 2015-01-01)Glass has high theoretical strength; however, microcracks on the surface of the glass greatly decrease the strength. Various methods to alleviate the effects of these cracks have been devised, including ion-exchange, mechanical abrasion, and acid etching. The goal of this experiment was to compare these methods by quantifying the strength via three-point bend testing to determine the modulus of rupture. Optical microscopy confirmed results, including the data that indicated that ion-exchange had the largest effect on strength by either widening or forcing shut cracks. Acid etching produced a moderate improvement in modulus of rupture by smoothing cracks. Finally, mechanical abrasion decreased strength but provided a more uniform strength distribution.
- Deposition and Single-Step Processing of YBCO Thick Films for Multilayered ElectronicsLangman, Jonathan; Lynch, Matthew (Virginia Tech Department of Materials Science and Engineering, 2005-09-22)The goal of this project was to successfully cofire a screen-printed yttrium bar ium copper oxide (YBCO) superconductor onto a low-temperature cofired ceramic (LTCC) substrate. The purpose was to investigate the compatibility of thick-film, high-temperature superconductors with multilayered ceramic (MLC) packages for cryogenic applications. Paste consisting of standard organics and YBCO powder of -325 mesh particle size was screen-printed onto Dupont 951 Green Tape. The system was cofired at temperatures ranging from 925°C to 975°C. The quality of the cofired system was characterized in several ways: Meissner diamagnetism, scanning electron microscopy, x-ray diffraction, and AC susceptibility tests were performed to determine the superconducting capability of the system. Samples cofired at 950°C retained some superconductivity after firing and showed the best compromise between sintering and degradation.
- Journal of Undergraduate Materials Research, Vol. 4 (2010)(Virginia Tech Department of Materials Science and Engineering, 2010-03-20)The Journal of Undergraduate Materials Research (JUMR) is a student-run scientific journal dedicated to research performed by students in materials science and related fields. The primary goal of this journal is to provide a platform for undergraduate researchers to publish their work. The secondary goal of this journal is to provide opportunities for undergraduates to practice their communication skills and gain experience working with reviewed publications. The fourth issue of the Journal of Undergraduate Materials Research continues to be a product of collaborative effort between the Virginia Tech Department of Materials Science and Engineering and the Virginia Tech Department of English. This issue features articles and student research focusing on a variety of subjects in materials science and engineering and other related fields. Volume 4 focuses on the benefits of collaborative learning at the undergraduate level between multiple universities and industries. The works within this issue represent students from universities in the United States and India, including Virginia Tech, the University of Hartford, Rose-Hulman Institute of Technology, Wright State University, South Dakota School of Mines, Georgia Institute of Technology, and Indian Institute of Technology in Chennai, India.
- A New Method of Generating and Storing Hydrogen for Fuel Cell ApplicationsFuller, Ian (Virginia Tech Department of Materials Science and Engineering, 2010-03-20)Current hydrogen technology relies on natural gas to generate the hydrogen and high pressure gas tanks to store the hydrogen. The new process illustrated here eliminates the negative aspects associated with these processes. Sodium borohydride, or any other metal hydride, is stored in solid form, thereby creating the most energy dense scenario as well as allowing for the use of current infrastructure. However, instead of using a precious metal catalyst, a cheap solid acid such as citric acid, is added to the metal hydride to regulate hydrogen production. With this method, a solid metal hydride/acid powder can be stored under low pressures until hydrogen is needed. At that point, water created from the fuel cells can be added in controlled amounts to the metal hydride/acid powder creating a controllable, humidified hydrogen flow perfect for fuel cell applications.
- Developing Functional Inks for Direct-Write SystemsRodriguez, Mitchell (Virginia Tech Department of Materials Science and Engineering, 2010-03-20)The field of Flexible Printed Electronics (FPE) carries great potential in reducing manufacturing costs and increasing versatility. The purpose of this research is to explore various ink chemistries and their suitability for deposition with regards to FPE. Titanium ceramics and silver-titanium-iron nanoparticles were utilized for their potential photocatalytic properties. The resulting inks experienced phase separation or hydrolyzed upon exposure to moisture, suggesting that a surfactant-based synthesis would better improve the inks’ durability.