Photochemical Image Formation Process for High Density PrintedCircuit Patterns

A number of optically active amino acids, both in the solid state and as sodium or hydrochloride salts in aqueous solution, have been exposed to ionizing radiation from a 3000 Ci60Co gamma-ray source to see if radioracemization might accompany their well-known radiolysis. gamma-Ray doses causing 55--68% radiolysis of solid amino acids typically engendered 2--5% racemization, while aqueous solutions of the sodium salts of amino acids which underwent 53--66% radiolysis showed 5--11% racemization. Amino acid hydrochloride salts in aqueous solution, on the other hand, showed little or no radioracemization accompanying their radiolysis. Both radiolysis and radioracemization were roughly proportional to gamma-ray dose in the range studied (1--36 x 10(6) rads). Mechanisms for the radioracemization of amino acids in the solid state and as aqueous sodium salts are discussed, and the absence of radioracemization for aqueous hydrochloride salts is rationalized. Isovaline, a non-protein amino acid which has been isolated from the Murchison meteorite, contains no alpha-hydrogen atom and is therefore incapable of racemization via the chemical mechanisms by which ordinary amino acids racemize. Nevertheless, isovaline suffers radioracemization in the solid state to an extent comparable to that shown by ordinary amino acids, as do its sodium and hydrochloride salts in the solid state. The sodium salt of isovaline in aqueous solution, however, fails to racemize during its radiolysis. Several implications of the newly described phenomenon of radiomization are pointed out for the fields of geochemistry and cosmochemistry.

This paper reports on a new method for the production of metallic microstructures with high aspect ratios that combines the advantages of injection moulding with the high precision replication of surfaces by galvanic and electroless metal deposition. LIGA made moulding tools are used to produce plastic “lost forms”, which are partially metallized by a silver cluster beam of high directionality to achieve electrical conductivity. For structures with an interconnected Ag layer at the bottom, galvanic metal deposition is used to form massive microstructures without voids. For isolated structures where contacting is not possible, chemical deposition was used for metal build-up starting from the metallized areas. However, massive electroless deposition beyond about 3 μm was not yet possible due to problems with internal stress in the deposited metal layer that cause delamination from the template. This stress must be reduced by appropriate modifications of the electrolyte.

Self-organized synthesis of micrometer scale silver disks by electroless metal deposition on Si-incorporated diamond-like carbon films

Soluting effect of amino acids on 1‑decyl‑3‑methylimidazolium bromide and 1‑dodecyl‑3‑methylimidazolium bromide as cationic surfactants and sodium dodecyl sulfate as anionic surfactant in aqueous solutions

Morphological and physicochemical disposition of silver (Ag) during redox-driven self-assembly of metal films on silica surfaces under equilibrium hydraulic conditions has been examined in real time in a novel electroless (EL) metal deposition cell by transmission UV-vis (T-UV) spectroscopy. Optical features due to localized surface plasmon resonance, surface plasmon polaritons, and photoluminescence from Ag and gold (Au) nanoarchitectures such as particles, clusters, and films were attributed by correlating T-UV with time-resolved scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Silver that deposited onto tin-sensitized surfaces in thin films nucleated nanoparticles when exposed to reductant or broadband light. Kinetic changes in plasmon features suggested four previously unrecognized time-dependent physicochemical regimes occur during consecutive EL deposition of Ag and Au onto tin-sensitized silica surfaces: self-limiting Ag activation; transitory Ag nanoparticle formation; transitional Au–Ag alloy formation during galvanic replacement of Ag by Au; and uniform metal deposition under controlled hydraulic conditions. Growth mechanisms at the surface, interior, and interface of the resulting thin metal films inferred from real time T-UV spectra were characterized by depth profile XPS analysis.

Knowledge of rutile (TiO2) solubility in aqueous fluids at high pressures and temperatures is of primary importance to a quantitative understanding of the high field strength elements (HFSE) transport in subduction zones. We attempted to redetermine rutile solubility in aqueous NaF solution and newly assess rutile solubility in aqueous Na2CO3 and Na2SO4 solutions through in-situ optical observations of the complete dissolution of a rutile grain in a hydrothermal diamond anvil cell (HDAC) at 823–974 °C and a pressure of approximately 0.9–1.8 GPa. The reproducibility of the experimental results in Na2CO3 solution was confirmed across individual experiments and repeated cycles within a single experiment. The rutile solubility in the aqueous sodium salt solutions was significantly higher than the previously reported solubility in pure H2O obtained with weight loss techniques using a piston–cylinder apparatus. While the increase in the solubility with added NaF was consistent with previous findings, the present results suggest that the solubility-promoting effect is smaller than previously reported. The high solubility in the aqueous sodium salt solutions may be attributed to the formation of Ti(IV) complexes with potential ligands (e.g., OH−, CO32−, SO42−, and F−) and sodium that remain to be characterized. Our findings indicate that sodium carbonate and sulfate-bearing fluids in subduction zone lithologies may play a role in efficiently transporting HFSE. A pertinent example of this could be the occurrence of carbonate and sulfate minerals in rutile-rich veins and fluid inclusions from high-pressure metamorphic rocks.

Ionic Polymer Metal Composites (IPMCs) are manufactured by electroless deposition of metal on Nafion. This deposition method results in the IPMCs with thickness between 0.17mm to 0.20mm with the electrode thickness of around a few m each. It is now generally accepted that on mechanical deformation IPMC produces charge thus making these materials potentially suitable for energy harvesting applications. Due to thin metal plating and inherited flexibility of the Nafion film the IPMCs suffer in stiffness that may be required for some energy harvesting applications. Also earlier works have shown that 0.20mm thick IPMC produce better battery charging than 0.17mm thick one. Hot pressing, using metal mold, Nafion films was employed to produce thicker and comparatively stiffer IPMCs electroded with Palladium metal. Palladium was used because of shorter manufacturing time. This IPMC shows improved energy harvesting. Due to the increased thickness these IPMCs also function as better capacitors than their conventional counterparts. On application of voltage, these IPMCs show charging and discharging effects of a capacitor. This property of IPMC may be useful for storing charge.

The following thermal data have been measured f or some of t he compounds and metals of cerium and neodymiumz (1) the heats of solution and dilution of the anhydr ous chlorides i n aqueous solution; (2) the changes in heat capacities of solution and dilution of the anhydrous chlorides in aqueous solution; (3) the heats of solution of the anhydrous chlorides and metals in aqueous hydrochloric acid; (4) the heats of solution of the hydrated chlorides in aqueous solution; ( 5) the heats of precipitation of the oxalates in aqueous oxalic acid solution; and (6) the heat capacity of neodymium metal in the temperature range of 0° to 250°C. In addition, the heats of solution and dilution of potassium chloride and oxalic acid hydrate in aqueous solution, and the heat capacity of tantalum metal from 0°C to 425°C have been measured.

During the last decades, the consumption of raw materials and energy in the world has faced a tremendous increase with a corresponding industrial waste volume increases, which treatment poses serious challenges. From an economical point of view, the waste has values as it contains valuable matters. Disposal of these streams without any further treatment is the environmentally unacceptable. The foreseeable upcoming depletion of metals, pure water and other raw materials forces us to find efficient technologies to recover those, and this thesis aims to investigate novel applications of a promising crystallization technology, Eutectic Freeze Crystallization (EFC) for the energy friendly (up to 90 % lower energy costs compared to evaporation) complete recovery of salt and fresh water from industrial streams. EFC operates around the eutectic temperature and composition of an aqueous solution and recovers the dissolved salts and fresh water from almost all aqueous salt or acid containing process stream, producing extremely pure ice and pure salts. The low operating temperature promotes safe and corrosion-free operation. Applications are possible in food, pharmaceutical, petrochemical and fertilizer industries etc. An introduction and the scope of this thesis are given in Chapter 1. This work focusses on the industrial application of EFC in (bio-)chemical and oil and gas industries. HrICP-MS is used as an analytical tool to assess the purity obtained using EFC. In Chapter 2, EFC was performed for an NiSO4 containing industrial stream from 1 liter scale batch set-up in the laboratory to an industrial scale continuous pilot plant (200 liter) at the production location of nickel sulfate. The heat transfer rate from the crystallizer could be maintained at 9 kW/m2 with ice and nickel sulfate production rates of 16 and 4 kg/h respectively. Since the major impurity in the starting solution is sodium, the quaternary point and the two eutectic solubility lines for the Na2SO4-NiSO4-H2O ternary system were also experimentally determined to investigate the limitations of EFC. Recrystallization of NiSO4?7H2O from produced with EFC into the NiSO4?6H2O is described in Chapter 3, and an effort of trace element analysis was performed by hrICP-MS. Within the range of 40 °C to 90 °C an optimal i.e. most pure product was found at 50 °C. Recrystallization mother liquor was recycled to assess the performance in industrial full continuous operation. It was found that the recrystallization occurs via the solution, allowing a redistribution of impurities. The results from hrICP-MS were used to calculate partition coefficients and distribution coefficients for impurity uptake in the NiSO4 crystals. Efforts to develop and perform elemental analysis of traces in the nickel sulfate system using hrICP-MS are presented in Chapter 4. First, contaminations in blanks and standard solution were assessed, and calibration curves were measured. Second, observed memory effects (i.e. the signal is influenced by the signal of the preceding sample or standard) were reduced by extensive flushing. Third, a strong decrease on the sensitivity during one single run consisting of blanks, samples and standard solutions was observed, and it was surprisingly found that this effect could not be eliminated by using internal standards. By correction of the signal decline from standard curves at different stages within one run, and by performing three runs reliable data could be collected. Chapter 5 describes how saline water from Kuwait oil production and valuable products were recovered by EFC in 1 liter batch experiment. Inclusions of mother liquor in the final ice product are below 0.05 wt%, and in NaCl?2H2O below 0.1 wt%. Then EFC was scaled up to batch 10 liter scraped wall crystallizer. A maximum ?T of 3.5 °C between the cooling liquid and the NaCl?2H2O/ice slurry could be maintained. The quality of final salt and ice products have a good reproducibility from 1 liter to 10 liter. Recrystallization were performed from NaCl?2H2O into NaCl as a further purification step , yielding more pure NaCl. Simulated shale gas water was treated with EFC (Chapter 6), and the ice products were deemed sufficiently pure to be reused in fracking fluid. By stepwise cooling down in a batch EFC process, the system of the solution with the eutectic points of BaCl2, NaCl and SrCl2 was characterized. At the end of the batch sequence the solution will consist of calcium chloride with minor impurities. The batch process was scaled up in a 200 liter scraped wall crystallizer, and a heat transfer rate of 4 kW/m2 over the heat exchangers could be maintained without excessive scaling inside the crystallizer. In Chapter 7, an industrial problem of removing Mg from hydrated nickel sulfates using state-of-the-art molecular simulations was investigated. Periodic Density Functional Theory (DFT) and cluster DFT calculations are used to study the crystal structures and phase stability of the hexahydrated and heptahydrated Ni and Mg sulfates and their mixed phases. The calculated lattice parameters of MSO4(H2O)n (M=Ni, Mg; n=6,7) crystals are in good agreement with available experimental data. The relative energy differences of the mixed phase for both hexahydrated and heptahydrated Ni/Mg sulfates obtained from both the periodic and cluster DFT calculations are generally less than kT (25.8 meV, T = 300 K), indicating that a continuous solid solution is formed.

Synthesis and characterization of TiO2–graphene nanocomposites modified with noble metals as a photocatalyst for degradation of pollutants

The dissolution and deposition of metals in solvents is widely known and used in a large range of applications, from electroplating to electro-machining. More recently, it has also been used for additive manufacturing (AM) at the sub-micron scale, since electroplated metals offer as-deposited high-quality metals (in terms of porosity and contamination) compared to other small scale AM techniques [1,2]. These intricate, high-quality metal structures have a range of applications in microelectromechanical systems, photonics or micro-robotics. However, the nature of the deposition process requires a conductive substrate to provide the electrons necessary for the localized reduction of metal ions. This requirement renders the direct fabrication of microelectronic devices using electrochemical small scale AM a challenge, as often deposition on electrically insulating substrates is required.Here, we present our work on electrohydrodynamic redox printing (EHD-RP), an electrochemical small scale AM technique, and our efforts towards deposition on various substrates. We’ll first introduce EHD-RP with a focus on our recent work on the deposition from aqueous metal salt solutions onto conductive substrates. We’ll then discuss strategies to expand the concept of EHD-RP towards deposition on non-conductive substrates and how electrically floating structures can be fabricated. These strategies render EHD-RP a versatile technique for metals microfabrication.[1] M. Nydegger, A. Pruška, H. Galinski, R. Zenobi, A. Reiser and R. Spolenak. Additive Manufacturing of Zn with Submicron Resolution and its Conversion into Zn/ZnO core-shell structures. Nanoscale, 2022[2] L. Hirt, A. Reiser, R. Spolenak and T. Zambelli. Additive Manufacturing of Metal Structures at the Micrometer Scale. Adv. Mater., 29(17), 2017

1. Effective rate constants (kef) for the hydrolysis of ethyl isovalerate in aqueous solutions containing from 4.95 to 41.3 mass % HCl, or from 2.52 to 94.0 mass % H2SO4, have been determined spectrophotometrically at 25°C. 2. The quantity kef increases with increasing acid concentration in aqueous HCl solutions. In aqueous sulfuric acid solutions, kef passes through a maximum at 49.8–55.9% H2SO4 and a minimum at 74.9% H2SO4. 3. In the hydrochloric acid and sulfuric acid solutions in question here (up to 74.9% H2SO4), the hydrolysis of ethyl isovalerate proceeds through an activated complex containing one un-ionized ester molecule and one hydronium ion carrying at least one solvation water molecule. The water molecule functions here as a nucleophilic agent. 4. The data obtained can be interpreted quantitatively by assuming that ionizatioa results in the formation of a protonized form of the ester and an unreactive complex in which the carbonyl group oxygen is bound to the hydronium ion. 5. Hydrolysis proceeds through the protonized form of the ester in sulfuric acid solutions with concentrations in excess of 74.9%.

We describe a new method for depositing patterned materials, based on non‐covalent trapping of ligands in solvent‐templated nanocavities created in aromatic, self‐assembled monolayer or polymer films. A model has been developed and tested to describe nanocavity formation and the ligand adsorption process, which occurs via ligand exclusion from ambient, aqueous solution into the hydrophobic nanocavities. Ligand adsorption rates and ligand adsorbate reactivity with solution species are governed by ligand size/geometry design factors identified using the model. Spatial control of adsorption is achieved via film photochemical changes that inhibit subsequent ligand adsorption/accessibility (UV or X‐ray) or displacement of entrapped ligands (50 keV electron‐beam) during film patterning. The reactivity of the adsorbed ligand is illustrated by the selective binding of PdII species that catalyze electroless metal deposition. Fabrication of high‐resolution (≈ 50 nm), positive‐tone patterns in nickel with acceptable feature‐edge acuity and critical dimension control (≈ 5 %) is demonstrated.

Electrolyte solutions are ubiquitous in materials in daily use and in biological systems. However, the understanding of their molecular and ionic dynamics, particularly those of their correlated motions, are elusive despite extensive experimental, theoretical, and numerical studies. Here we report the real-space observations of the molecular/ionic-correlated dynamics of aqueous salt (NaCl, NaBr, and NaI) solutions using the Van Hove functions obtained by high-resolution inelastic X-ray scattering measurement and molecular dynamics simulation. Our results directly depict the distance-dependent dynamics of aqueous salt solutions on the picosecond time scale and identify the changes in the anion-water correlations. This study demonstrates the capability of the real-space Van Hove function analysis to describe the local correlated dynamics in aqueous salt solutions.

Ion-exchange sorption of K+ and Na+ from their mixture on X-ray-amorphous and crystalline Sn(IV) hydrophosphates was studied. These sorbents exhibit a high selectivity for K+. Amorphous Sn(IV) hydrophosphate can be used for efficient purification of aqueous sodium salt solutions to remove potassium impurity.