Frontiers of Materials Award Symposium: Radiation Processing of Materials: Session I: Radiation Synthesis and Processing of Materials
Program Organizers: Jessika Rojas, Virginia Commonwealth University
Thursday 8:30 AM
March 18, 2021
Room: RM 6
Location: TMS2021 Virtual
8:30 AM
Introductory Comments: Frontiers of Materials Award Symposium: Radiation Processing of Materials: Jessika Rojas1; 1Virginia Commonwealth University
Introductory Comments
8:35 AM Keynote
Ionizing Radiation in the Synthesis and Processing of Nanocomposites for Medical and Environmental Applications: Jessika Rojas1; 1Virginia Commonwealth University
It is frequently thought that ionizing radiation, such as alpha, beta, gamma, X-rays causes deleterious effects on materials. Although true under some circumstances, ionizing radiation is also a powerful tool for materials processing in areas such as controlled synthesis of nanostructures, materials’ surface, and nanostructure proprieties modification, among others. For example, it has been evidenced that radiation chemistry for materials’ synthesis can be performed at ambient conditions (no thermal input required), it eliminates the need for reducing agents, and it does not generate toxic byproducts. This talk highlights the use of ionizing radiation as a synthesis and processing tool of inorganic nanomaterials for applications in medicine and catalysis. Initially, the synthesis of metal nanoparticles supported on various materials such as ceramic nanoparticles and 3D supports will be discussed. A synergism between nanoparticles and support often leads to enhanced properties. Finally, X-ray irradiation as a novel surface treatment to improve the photocatalysis performance of TiO2 will be described in light of the materials’ surface chemistry.
9:05 AM Invited
Radiation-grafting of Smart Polymers for Potential Biomedical Applications: Emilio Bucio1; 1Nuclear Science Institute at National University of Mexico
Recently investigated smart or intelligent polymeric materials suitable for tissue engineering, regenerative medicine, and drug-eluting medical devices were synthesized by novel radiation-grafting method. Smart biomaterials in the form of polymeric films, sutures, catheters or cotton gauzes were prepared via gamma radiation-grafting of pH and thermo sensitive polymers using either the pre-irradiation or the direct method. The use of synthetic materials has become an established practice in several areas of surgical treatment. Radiation-grafting of acrylic monomers, such as acrylic acid, methacrylic acid, N-isopropylacrylamide, etc. onto medical devices (suture thread, cotton gauze, silicon rubber, polyurethane catheter, etc.) can endow the medical device with a remarkable capability to host drugs and to sustain their release for several hours or days.
9:35 AM Invited
Direct Prompt Synthesis of Radioactive Nanoparticles (Prompt Nano Radioisotopes): Carlos Castano1; 1Missouri University of Science and Technology
Most nanomedicines use nanostructures as carrier for drugs, making their therapeutic effectiveness dependent on the ability to deliver the drug to the interior of cells (endocytosis). Nano Radioisotopes do NOT require endocytosis, since approaching the cell from the outside (targeting or retention) can be sufficient to kill the cell (i.e. induce apoptosis). In this case, the therapeutic load is radiating energy with sufficient penetration into nearby cells. Radiation methods for the creation of nanostructures also have various advantages over chemical ones. First, the reductive potential induced by radiation is essential instantaneous and uniform throughout the precursor solutions. Finally, the reducing agent is radiation, ameliorating potential contamination issues. Most radioactive nanostructures (non-prompt) are produced by activating precursor elements and then performing radiochemical procedures to make nanostructured forms. Prompt Nano-Radioisotopes make radioactive isotopes in nano form ready to use, reducing the need for facilities to manipulate radiochemicals or radiopharmaceuticals.
10:05 AM Invited
Probing and Processing Nanomaterials and Devices with Radiation: Cory Cress1; 1U.S. Naval Research Laboratory
Radiation sources and beams lines provide an effective means for systematically probing extrinsic and intrinsic disorder effects in nanomaterials and nanoelectronic devices. Through a series of 60Co radiation effects studies, I will show how extrinsic disorder, such as trapped-charges in dielectrics, influence the electrical performance of carbon nanoelectronics devices. I will also discuss ion-beam induced intrinsic disorder effects, those that stem from defects within a material, using graphene and single-walled carbon nanotubes (SWCNTs) as the model material system. This discussion focuses on how dimensional confinement influences the radiation degradation rate and that the greater confinement in SWCNTs, than graphene, enhances their radiation tolerance. Beyond radiation effects characterization, ion-beam processing has wide applicability in modifying the structural and physical properties of nanomaterials. In particular, I will discuss novel work employing hyperthermal ions (5 – 350 eV) and He ions (20-30 keV) from a helium ion microscope, to substitutionally dope graphene (N ions), strain few-layer graphene with defects (Ar ions), and direct-write defects in transition-metal dichalcogenides and FeRh. To conclude, I will by outline the current challenges and vast prospects of this field.
10:35 AM Invited
Nanochannels, Nanowires, and Nanotubes Fabricated by Ion-track Nanotechnology: Marķa Eugenia Toimil-Molares1; 1GSI Helmholtz Center
This talk will illustrate how ion-track nanotechnology provides an excellent platform (i) to fabricate tailored nanochannel sensors, (ii) to fabricate nanowires and investigate their size-dependent properties, and (iii) to develop 3-D and multicomponent nanostructure assemblies. Membranes with parallel nanochannels are fabricated by swift heavy ion irradiation and subsequent chemical etching of the ion-tracks. In addition, membranes with interconnected tilted nanochannels are obtained by applying consecutive ion irradiation steps at several incident angles. Nanochannel density and orientation, as well as diameter and geometry, are adjusted by the irradiation and etching conditions, respectively. Nanochannel diameter is typically varied between ~20 nm and ~few µm. The length, given by the polymer foil thickness, amounts up to ~100 µm. Subsequent electrodeposition in the channels results in nanowire arrays and highly ordered 3-D nanowire ensembles of various materials. Recent developments achieved on the electrodeposition of metal (Cu, Au1-xAgx), semiconductor (ZnO and p-Cu2O) and semimetal (Bi, Sb) nanowire arrays and networks will be presented.
11:05 AM Invited
Ionizing Radiation Synthesis of Novel Fabrics for Extraction of Uranium from Seawater: Mohammed Al-Sheikhly1; 1University of Maryland
The world’s oceans contain more than 4.5 billion tons of uranium; however access to this resource is limited by the ability to extract uranium from seawater efficiently. Lacing fabric substrates with chemical functionalities specific for uranium adsorption is one approach to meeting this challenge. Advanced adsorbent materials are being developed using polymeric substrates with high chemical stability, excellent degradation resistance and improved mechanical properties. Fabrics include polypropylene, nylon and advanced Winged Fibers from Allasso industries featuring extremely high surface areas for improved grafting density. Using 10 MeV electron beam linear accelerator, the various fabrics have been irradiated over a wide range of dose rates, total doses and temperatures. Innovative vinyl phosphate and oxalate exhibiting high distribution coefficients and selectivity for uranium along with excellent potential for free radical polymerization have been utilized in the functionalization of the fabric substrates. Azo compounds with higher selectivity have also been utilized but have required the use of a grafted chemical precursor. Attachment of the chelating adsorbent or its precursor to the substrate polymer is maximized through the optimization of numerous variables including monomer concentration, dose rate, total dose, solvent and temperature.
11:35 AM Live Question and Answer