Supramolecular Nature of Multicomponent Crystals Formed from 2, 2'-Thiodiacetic Acid with 2, 6-Diaminopurine or N9-(2-Hydroxyethyl) adenine.

The synthesis and characterization of the multicomponent crystals formed by 2,2′-thiodiacetic acid (H2tda) and 2,6-diaminopurine (Hdap) or N9-(2-hydroxyethyl)adenine (9heade) are detailed in this report. These crystals exist in a salt rather than a co-crystal form, as confirmed by single crystal X-ray diffractometry, which reflects their ionic nature. This analysis confirmed proton transfer from the 2,2′-thiodiacetic acid to the basic groups of the coformers. The new multicomponent crystals have molecular formulas [(H9heade+)(Htda−)] 1 and [(H2dap+)2(tda2−)]·2H2O 2. These were also characterized using FTIR, 1H and 13C NMR and mass spectroscopies, elemental analysis, and thermogravimetric/differential scanning calorimetry (TG/DSC) analyses. In the crystal packing the ions interact with each other via O–H⋯N, O–H⋯O, N–H⋯O, and N–H⋯N hydrogen bonds, generating cyclic hydrogen-bonded motifs with graph-set notation of ��22 (16), ��22 (10), ��23 (10), ��33 (10), ��22 (9), ��23 (8), and ��24 (8), to form different supramolecular homo- and hetero-synthons. In addition, in the crystal packing of 2, pairs of diaminopurinium ions display a strong anti-parallel π,π-stacking interaction, characterized by short inter-centroids and interplanar distances (3.39 and 3.24 Å, respectively) and a fairly tight angle (17.5°). These assemblies were further analyzed energetically using DFT calculations, MEP surface analysis, and QTAIM characterization

Manufacturing of carbon-based hybrid nanocomposites with engineered functionalities via Laser Ablation Synthesis in Solution (LASiS) techniques

Carbon-based composite materials have long been fabricated and extensively used in our daily lives. In the past decades, with rapid development of nanotechnology, these class of material have gained even more attention owing to their outstanding properties which directly results in their prospects to revolutionize technological development in many fields, ranging from medicine to electronics. Nevertheless, for certain applications, including electrochemical energy storage/conversion devices, the chemically inert nature of these materials creates obstacles and thus requires their coupling with other active species. This thesis explores the use of Laser Ablation Synthesis in Solution (LASiS) in tailoring promising strategies and pathways for the synthesis of carbon-based hybrid nanocomposites, more specifically herein I present (1) the synthesis of metal-oxide/ reduced-graphene-oxide hybrid nanocomposites and the rational-design of their structure–property for selective improvements in electrocatalytic/ and or supercapacitive properties, (2) the fabrication of nanoparticles within Metal-Organic Frameworks (MOFs) and characterization of their performance as electrocatalysts for Oxygen Reduction Reaction (ORR). For each synthetic route, a comprehensive analysis of reaction pathways, formation mechanisms and structure-property relationship is developed taking into account elemental, structural, physicochemical and morphological characterizations of the final products, setting the ground for use of LASiS for the rational design and synthesis of a wide library of diverse carbon-based nanocomposites structures in future

Langmuir-blodgett films of organic charge-transfer complexes

This thesis is concerned with the preparation of floating films of electrically conductive organic charge-transfer complexes and their subsequent transfer to solid substrates by the Langmuir-Blodgett (LB) technique. Characterisation of the morphology (using ellipsometry, surface profiling, optical and scanning electron microscopy, energy dispersive spectroscopy and optical absorption spectroscopy) and electrical properties (at room temperature and low temperature) of the resulting multilayer structures is discussed. Three different systems were investigated: (i) mixed films containing the long chain tetrathiafulvalene (TTF) derivative octadecanoyl-TTF (ODTTF) and either octadecanoic acid (OA) or pentacosa-10,12-diynoic acid (PA); (ii) pure films of the charge-transfer complex Ν-octadecylpyridiniura-bis-(4,5-dimercapto-1,3-dithiole-2- thione) palladium (Ci8Py-Pd(dmit)2); and (iii) pure films of the charge-transfer complex N-octadecylpyridinium-bis-(4,5-dimercapto-1,3-dithiole-2-thione) nickel (CigPy- Ni(dmit)2). Some interesting electrical properties were observed in these films. Also, Ci8Py-Ni(dmit)2 has been incorporated as the active layer in a thin film field effect transistor structure. Carrier mobility values of 1.9 ± 0.5 x l0(^-5) cm(^2) V(^-1) S(^-1) and 0.3 ± 0.1 cm(^2) V(^-1) s-(^-1) were calculated from the device characteristics, before and after doping with iodine, respectively In the case of films containing ODTTF, a maximum room temperature in-plane dc conductivity after iodine doping of 2±lxl0(^-2) S cm(^-1) was recorded. This conductivity was found to be strongly dependent on the molar ratio of the two components present in the film. The behaviour has been explained using two-site percolation models. For C(_18)Py-Pd(dmit)(_2) and C(_18)Py-Ni(dmit)(_2), the properties of the floating layers and transferred films were found to be influenced by the exact experimental conditions. Ci8Py-Pd(dmit)(_2) films were conductive as deposited, with a stable maximum room temperature in-plane dc conductivity value of 1.5±1.0xl0(^-l) S cm(^-1). C(_18)Py-Ni(dmit)(_2) samples became conductive after exposure to iodine vapour, with a stable peak conductivity value of 1.3±0.8 x10(^-1)S cm(^-1)

TOWARDS ENVIRONMENTALLY SUSTAINABLE, HIGH-PERFORMANCE, LIGHTWEIGHT COMPOSITES FOR AUTOMOTIVE APPLICATIONS

The increasing public demand in the world automotive industry to improve the environmental sustainability of their manufactured vehicles without sacrificing drivers\u27 comfort and safety and the high cost of lightweight materials have driven researchers to reconsider materials used in the automotive application. Thus, this work aims toward the production of environmentally sustainable, high-performance, lightweight composites, utilizing recycled carbon fibers (RCFs) and pyrolyzed tire particles (PTPs) reclaimed from pyro-gasification of CFRP wastes and end-of-life tires (ELTs), respectively, as reinforcements for cardanol-based epoxy resins. The fabricated composites exhibited rubbery-like behavior at 25 °C. Spectroscopic, rheological, physical, thermal, thermomechanical, and mechanical characterizations were performed to fundamentally understand the processing-structure-property relationships of the manufactured composites. In addition, laminates interleave with cardanol-based epoxy resin, and RCF-reinforced cardanol-based epoxy composites widen the energy dissipation to lower temperatures, implying better fracture toughness. For the hybrid composite, the interlocking effect of combining RCFs and PTPs resulted in higher Tg and better thermal stability compared to the composites with a single type of reinforcements. These material behaviors demonstrate that these composites represent interesting candidates for producing sustainable, lightweight, and low-cost anti-vibration components

Pinellas Plant facts

The Pinellas Plant, near St. Petersburg, Florida, is wholly owned by the United States Government. It is operated for the Department of Energy (DOE) by GE Aerospace, Neutron Devices (GEND). This plant was built in 1956 to manufacture neutron generators, a principal component in nuclear weapons. The neutron generators built at Neutron Devices consist of a miniaturized linear ion accelerator assembled with the pulsed electrical power supplies required for its operation. Production of these devices has necessitated the development of several uniquely specialized areas of competence and supporting facilities. The ion accelerator, or neutron tube, requires ultra clean, high vacuum technology; hermetic seals between glass, ceramic, glass-ceramic, and metal materials; plus high voltage generation and measurement technology. The existence of these capabilities at Neutron Devices has led directly to the assignment of other weapon application products: the lightning arrester connector, specialty capacitor, vacuum switch, and crystal resonator. Other product assignments such as active and reserve batteries and the radioisotopically-powered thermoelectric generator evolved from the plant`s materials measurement and controls technologies which are required to ensure neutron generator life