General Poster Session: Nanostructured and Heterostructured Materials
Program Organizers: TMS Administration
Tuesday 5:30 PM
February 25, 2020
Room: Sails Pavilion
Location: San Diego Convention Ctr
Cancelled
N-61: Confined Laser Shock Detonation to Form Nanodiamonds with Nitrogen-vacancy Center: Qiong Nian1; Rui Dai1; 1Arizona State University
Florescent nanodiamonds (NDs) with color centers, can find board applications nowadays, from bio-imaging and drug delivery, to quantum communication and quantum computing. However, existing synthesis methods of NDs are usually limited by high cost and low yield due to keeping extreme conditions such as high pressure, high temperature in vacuum chambers. Herein, a confined laser shock Detonation (CLSD) method is introduced to fabricate NDs economically. During CLSD, the laser ablation generated carbon plasma condenses the meta-stable graphite particles into diamond phase and deposits them onto a glass substrate under ambient conditions. More than that, florescent NDs are obtained with nitrogen source material embedded in CLSD. To understand the mechanisms involved in this process, we developed a bottom-up computational modeling to investigate the process-structure relation. The fundamental understanding provides critical pressure and temperature to form the NDs as well as nitrogen-vacancy center, and paves a way for further process optimization.
N-62: Monodisperse Polystyrene Spheres: Studies on the Effects of Reaction Parameters on Particle Diameter and Colloidal Stability: Ikhazuagbe Ifijen1; Esther Ikhuoria2; Aireguamen Aigbodion1; Stanley Omorogbe1; 1Rubber Research Institute of Nigeria; 2University of Benin
Herein, the synthesis of highly monodisperse polystyrene (PS) microspheres via surfactant-free emulsion polymerization process was successfully carried out. Various reaction conditions such as initiator amount, monomer amount, reaction temperature and stirring speed were varied with a view to studying the effect of these polymerization parameters on the particle diameter and colloidal stability of the synthesized PS microspheres. Microscopic analysis revealed that the as-synthesized particles are spherical in shape without any form of agglomeration. TGA analysis revealed that the prepared PS sample completely degrades at 465 oC. DLS analysis showed a reduction in the average particle diameters of the as-synthesized PS microspheres as the reaction temperature, stirring speed and initiator amount increased, whereas an increase in average particle diameter was observed with increased monomer amount. Zeta-potential values ranging from -30.10 mV to -39.50 mV which is indicative of stable colloidal dispersion of particles were seen for all the synthesized PS samples.
N-65: The Unusual Effect of Alloying Elements on Microstructure and Texture Development during HPT in Single Phase Zn-alloys: Wiktor Bednarczyk1; Maria Wątroba1; Jakub Kawałko1; Nong Gao2; Marco Starink2; Piotr Bała1; Terence Langdon2; 1AGH University of Science and Technology; 2University of Southampton
High pressure torsion (HPT) processing in most cases produces an ultrafine-grained microstructure characterized by high angle grain boundaries and texture resulting from the characteristic deformation mechanism for the particular alloy group. Deviations from expected texture are rarely observed in single phase alloys.In this work pure zinc and low-alloyed Zn-Ag and Zn-Cu alloys were processed by HPT for 1/2–10 turns. Based on microstructural investigations three different deformation behaviors were distinguished. Pure Zn presents grain refinement up to 2 turns, and on further deformation grain growth was observed with crystallographic texture consistent with activation of 2nd order pyramidal slip system. After 5 turns the Zn-Cu alloy presents typical basal fiber texture with misorientation angle of all grain boundaries < 30°, while the Zn-Ag alloy presents significant grain growth and previously not observed sharp texture with 0001 direction parallel to the tangential direction and 11-20 direction perpendicular to the shearing plane.
N-66: Wallpapering-inspired Approach to Create Wrinkles in a Single-layer Graphene: Won Il Park; Sang Il Lee1; Jae Hyung Lee1; Dong Won Yang1; Jae Hyeok Shin1; Won Jun Chang1; 1Hanyang University
Surface corrugations (i.e., ripples and wrinkles) in atomically-thin two-dimensional (2D) materials are often considered to be undesirable imperfections. However, new light has recently been shed on the potential of wrinkles since it is found that these wrinkles can impose positive changes on the 2D materials. Diverse approaches have thus been applied to intentionally produce and manipulate wrinkles, but it remains a challenge to precisely control the position, orientation, and shape of the individual wrinkles. In this study, we propose a novel wallpapering-inspired strategy to create wrinkles in a desired location and direction of single-layer graphene. This approach enables to produce well-controlled graphene wrinkles (e.g., microscale lattice patterns of graphene wrinkles with nanometer-scale width and height). The detailed wrinkling process and corresponding mechanism were characterized by correlating the size and shape of graphene wrinkles with their mechanical behaviors.