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  • Undergraduate Poster Abstracts
  • Materials Engineering (Includ. Ceramics/Textiles)

    THU-745 REINFORCEMENT PARTICLE SIZE IMPACT ON COLD ROLLED BONDED (CRB) MANUFACTURED LAMINATE COMPOSITES

    • Elias De Haro Jr. ;
    • Mina Bastwros ;
    • Gap-Yong Kim ;

    THU-745

    REINFORCEMENT PARTICLE SIZE IMPACT ON COLD ROLLED BONDED (CRB) MANUFACTURED LAMINATE COMPOSITES

    Elias De Haro Jr.1, Mina Bastwros2, Gap-Yong Kim2.

    1Kirkwood Community College, Cedar Rapids, IA, 2Iowa State University, Ames, IA.

    Cold rolled bonded (CRB), a solid state welding fabrication process, has been used to manufacture laminate metal composites on an industrial scale. In this study, the role of reinforcement particle sizes, ranging from nanoscale to micron scales, on the bond strength between laminate layers of CRB-produced aluminum-silicon-carbide (Al1100-SiC) composite has been investigated. The bond strength was tested using a T-peel machine. A scanning electron microscope was used to characterize the bond structures between peeled substrate. According to test data, nanoparticles did not strengthen the bond between laminate layers, but instead decreased it when compared to pure, non-reinforced, bonded aluminum. On the other hand, the larger micron-sized particles increased the bond strength between laminate layers. The 10 µm particles showed a significant increase in bond strength over the unreinforced and nanoparticle-reinforced aluminum. The largest particle size (60 µm) samples had substrates break during the T-peeling test due to the significant increase in bond strength, indicating a bond strength higher than the strength of the aluminum substrate. It has been concluded that larger particles provide a stronger bond due to mechanical interlocking caused by particle morphology.

    THU-746 CHARACTERIZATION OF FLEXIBLE MICRO-/NANO-PATTERNED POLYDIMETHYLSILOXANE THIN FILMS FOR IMPROVED USABILITY OF BIOELECTRONICS

    • Kate Newcomer ;
    • Marina Scharin ;

    THU-746

    CHARACTERIZATION OF FLEXIBLE MICRO-/NANO-PATTERNED POLYDIMETHYLSILOXANE THIN FILMS FOR IMPROVED USABILITY OF BIOELECTRONICS

    Kate Newcomer1, Marina Scharin2.

    1University of California, San Diego, La Jolla, CA, 2Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, DE.

    Altering cellular processes at the nano or micrometer scale improves biomedical devices for in vitro applications. Polydimethylsiloxane (PDMS)-based materials are known for their biocompatibility and optical transparency, making them ideal candidates for cell-based biosensors and microfluidic devices. PDMS substrates also show promise in the development of microelectrode arrays (MEAs). Sputtered with transparent electrodes, PDMS substrates can be used in opto-electronic biosensors. However, due to the low surface energy and the strong hydrophobicity of the PDMS materials, the usage of PDMS in areas such as substrate materials for biosensors and microelectrode arrays is limited. The strong hydrophobicity of PDMS materials is largely due to the adhesion behavior of the thin film layers. The aim of this project is to compare different electrode materials, in particular, titanium (Ti) and indium-tin-oxide (ITO), in developing flexible nano-patterned biocompatible polymer-based thin films for transparent bioelectrodes. Fabrication of the samples will be carried out by manufacturing 3 different types of PDMS; soft, hard, and cross-linked; and then depositing an electrically conductive layer, such as Ti or ITO via physical vapor deposition. The electrical conductivity; such as sheet and specific resistance, flexibility, and biocompatibility of the samples; will then be tested to determine the ideal material for the development of bioelectrodes and MEAs. The results will improve the usability of biomedical devices.

    FRI-746 CHEMICAL VAPOR DEPOSITION FOR REPRODUCIBLE FABRICATION OF HIGH-QUALITY, VERTICALLY-ALIGNED CARBON NANOTUBE ELECTRODES FOR LI-AIR BATTERIES

    • Scott Tan ;
    • Mazdak Hashempour ;
    • Thomas Batcho ;
    • Carl Thompson ;

    FRI-746

    CHEMICAL VAPOR DEPOSITION FOR REPRODUCIBLE FABRICATION OF HIGH-QUALITY, VERTICALLY-ALIGNED CARBON NANOTUBE ELECTRODES FOR LI-AIR BATTERIES

    Scott Tan1, Mazdak Hashempour2, Thomas Batcho2, Carl Thompson2.

    1Pomona College, Claremont, CA, 2Massachusetts Institute of Technology, Cambridge, MA.

    Vertically-aligned carbon nanotubes (VACNTs) are ideal candidates for Li-air battery cathodes due to desirable characteristics such as high conductivity, porosity, and surface area, but the previous chemical vapor deposition (CVD) fabrication technique produced electrodes with inconsistent height and density. Reproducible height and density are necessary for electrodes to be coated via atomic layer deposition, a technique used to modify carbon nanotubes for potential improvement in battery stability. This project focused on optimizing the CVD technique to consistently produce VACNT electrodes with uniform height and areal density. Optical microscopy and weight measurements of VACNT electrodes grown via the previous CVD method displayed a gradient for height and areal density between successive samples in a batch. This gradient was dependent on proximity to the source of gas flow, which suggested a shortage of ethylene in the system. To counteract this, ethylene gas flow was increased, which successfully reduced variation between samples. However, consistent height measurements with inconsistent areal densities implied deposition of unwanted species onto the substrates at ethylene flow rates above 125 standard cubic centimeters per minute. Other parameters were also optimized for the updated CVD method. The system was automated via microprocessor control to reduce procedure variation between experiments. The relative standard deviation between samples grown under the same conditions was reduced 4-fold for height and 3-fold for areal density using the new fabrication method. VACNT electrodes have been assembled and tested in Li-air batteries and imaged via SEM and TEM to confirm high-quality carbon nanotube formation.

    FRI-745 SOFT TEMPLATE SYNTHESIS OF MESOPOROUS NB DOPED TIO2

    • Lauren Lopez ;
    • Olivia Graeve ;
    • Shuang Qiao ;

    FRI-745

    SOFT TEMPLATE SYNTHESIS OF MESOPOROUS NB DOPED TIO2

    Lauren Lopez, Olivia Graeve, Shuang Qiao.

    University of California, San Diego, La Jolla, CA.

    Mesoporous materials exhibit large, accessible pores and a large surface area. These pores are capable of encapsulating larger molecules for biocatalysis. Enhancing the electrical conductivity through a doping process may improve the function of encapsulated biocatalysts. The purpose of this project is to synthesize electrically conductive nanostructures to serve as reactors for biocatalysts that require an electrically conductive environment to function. Mesoporous titanium dioxide doped with niobium was synthesized by using a soft-template method. X-ray diffraction was used to confirm the synthesized powder material phases. Scanning electron microscopy (SEM) revealed a uniform doping of niobium throughout the material. Transmission electron microscopy allowed for a closer look at the powder morphology, revealing a mesoporous structure. The Brunauer-Emmett-Teller test (BET) confirmed the mesoscale pores by revealing 2 pore sizes, 6 and 9 nm. The surfactant and titanium precursor amount as well as the calcination temperature has been varied to change the pore size. A range of powders with differing pore sizes have been synthesized to analyze electrical and thermal conductivity changes. As part of a collaborative project, enzymes will be encapsulated within the pores for future biocatalyst studies.