A novel silicone-epoxy oligomer was synthesized and evaluated for its use as the polymer in photopolymerizable dental composites. This synthesized oligomer contained rigid and non-rigid groups with 1-8 epoxy functionalities as characterized using 1H NMR and 29Si NMR and MALDI-TOF analysis. In comparison to the traditional BisGMA/TEGDMA monomer system, the photo-polymerized silicone-epoxy demonstrated significantly improved material properties (148% greater elastic modulus, 12% greater ultimate strength, 48% greater fracture toughness), as well as 61% lower polymerization shrinkage and 58% lower polymerization stresses. Furthermore, the silicone-epoxy system demonstrated enhanced resistance to degradation of its material properties after accelerated (24hr) aging, i.e. exposure to severe hydrolytic (boiling in ethanol at 100 ᵒC), oxidative (exposed to 5% H2O2), and low pH (0.05M acetic acid) stress. Under these conditions, the properties of conventional BisGMA/TEGDMA systems deteriorated by 22-47%, while the properties of the silicone-epoxy composites decreased by 2-10%. Bisphosphonate additives enhanced the precipitation of mineral in a dose-dependent manner, but inhibited polymerization due to interactions with epoxy groups. Bisphosphonate additives also dose-dependently demonstrated anti-bacterial efficacy as demonstrated using live-dead, MTT and crystral violet assays. The silicone-epoxy polymer was demonstrated to be biocompatible when compared to tissue culture plastic. When calcium fluoride was incorporated into this system, fluoride was found to be released quantities significant enough to engender anti-bacterial effects. In summary, the designed multifunctional dental resin exhibits higher stability as demonstrated by lower chemical, mechanical and enzymatic degradation.

High-energy flash cure lamps process thick film materials (<10 um) over large areas (<100 cm2) within milliseconds and are capable to deliver higher energy and power densities (20 J/cm2 and 20 kW/cm2) allowing for a more complete curing and elimination of flaws that would exist in conventional treatment. Click reactions are especially attractive for patterned devices as they have minimal shape change during curing and have a more predictable structure compared to free radical acrylate polymerization. Pentaerythritol tetrakis(3-mercaptopropionate) and 2,4,6-Triallyloxy-1,3,5-triazine were combined at 3:4 by weight and then spin coated on copper foil substrates. The solutions were processed both thermally and with exposure to a xenon flash bulb. Thermal treatment consisted of heating the sample at 80°C on a hot plate over night. Flash curing was accomplished using a Novacentrix Pulseforge 1300 system. The flash lamp curing fluence and intensities were varied to determine their effects on degree of cross-linking, dielectric constant, breakdown field and energy storage. The degree of cross-linking was determined through comparative FTIR studies. Dielectric constant was measured using an Agilent 4294a impedance analyzer from 100 Hz-100 MHz with a two terminal setup. Breakdown strength and energy density measurements were taken using Radiant Technology's Precision Ferroelectric tester with a 10 kV source. The printed films averaged 1-3 microns thick as observed by an SEM cross section measurement. It was found that dielectric constant varies with both treatment intensity and fluence. Energy densities were calculated using the ideal capacitor equation and ranged from 1.5-4.8 J/cm3.

Mg-Si thin films were systematically studied using combinatorial approach by co-sputtering with Mg and Si targets. Single phase of Mg2Si appeared around the stoichiometric composition region, and in Mg-rich region (Mg/Si>4) Mg2Si and Mg phases coexisted. The transition of electrical conduction type from n-type to p-type occurred near the stoichiometric composition region where the strongest peak of Mg2Si appeared in the XRD patterns and the Raman scattering spectra. The p-type conduction was observed in Mg-poor region near the stoichiometric composition region. The results of first principle calculation suggest that Mg vacancy may cause p-type conduction.

The homogeneous dispersion of carbon nanotubes (CNTs) in a polymer matrix is a critical parameter that significantly affects the electrical and mechanical properties of CNT-based composite materials, and represents an important challenge to overcome during the manufacturing process of these materials. In our work we used double-stranded DNA to facilitate the dispersion of multi-walled CNTs in solution prior to the integration in epoxy resin PRIME 20 LV. Composites containing DNA-wrapped CNTs were prepared using sonication at 0.5 wt.% CNT loading and the dispersion level in the composite CNT/PRIME 20 LV was observed under an optical microscope. Nanoindentation experiments were conducted to determine the local mechanical properties of the CNT/PRIME 20 LV composites films after cure, showing a significant improvement in their distribution across the sample surface as a result of the enhanced CNT dispersion by DNA. An electrical test to assess the stability of the CNTs dispersion in the resin was developed by measuring the conductivity of the composite mixture before cure in time. Results of the electrical measurements indicate that the CNT/PRIME 20 LV mixture with DNA-wrapped CNTs is stable for several days after preparation.

The present work focuses on the synthesis and evaluation of the antimicrobial activity of ZnxMg1-xO solid solutions. ZnxMg1-xO solid solutions were synthesized through the thermal decomposition of ZnMg-precursor synthesized in aqueous and ethanol solutions via a two-steps process. The antimicrobial activity of ZnxMg1-xO solid solution against E. coli was evaluated using the spread plate method in presence of ZnxMg1-xO powder of different contents of Zn species, ‘x’. The powder concentrations evaluated were 500, 1000, and 1500 ppm. Zn0.10Mg0.90O powders exhibited a bacterial growth inhibition between 38% and 100% when the powder concentration increased from 500 up to 1500 ppm, respectively. A decreasing trend was observed for x = 0.30 and above; the corresponding bacterial growth inhibition was 12%, 6%, and 5% when the particles concentration was, respectively, 500, 1000, and 1500 ppm. X-Ray diffraction analyses suggested the incorporation of Zn ions into the MgO lattice for ‘x’ values below 0.10, enhancing the antimicrobial activity; the formation of two isolated oxide phases observed at larger ‘x’ values (e.g. x = 0.30 and x = 0.50 Zn), could explain the detected inhibition of the corresponding antimicrobial activity.

Atomic-resolution structural and spectroscopic characterization techniques (scanning transmission electron microscopy and electron energy loss spectroscopy) are combined with nanoscale electrical measurements (conductive atomic force microscopy) to study at the atomic scale the properties of graphene grown epitaxially through the controlled graphitisation of Si-face and C-face hexagonal SiC(0001) substrates by high temperature annealing. A scanning transmission electron microscopy analysis, carried out at 60KeV of beam energy, below the knock-on threshold for carbon to ensure no damage is imparted to the film by the electron beam, demonstrates that the buffer layer present on the planar SiC(0001) Si-face delaminates from it on the (11-2n) facets of SiC surface steps, In addition, electron energy loss spectroscopy reveals that the delaminated layer has a similar electronic configuration to purely sp2-hybridized graphene. A thin amorphous film is found on the C-face, instead, which strongly suppresses epitaxy with the SiC substrate. Structurally, the amorphous area is inhomgeneous, as its Si-concentration gradually decreases while approaching the first graphene layer, which is purely sp2-hybridized. Based on these features, we discuss differences and similarities between the C-only buffer layer that forms on the Si-face of SiC with respect to the thicker C/Si amorphous film of the C-face.

We discuss the advantages of V2O5-P2O5-Fe2O3-Li2O glass-ceramics as a cathode for lithium-ion batteries. The glass was prepared by using the melt quenching method. The glass-ceramics were produced by heat treatment in air. LixV2O5 crystal was only confirmed as the precipitated phase and the degree of crystallinity was approximately 90%. The total capacity of the glass-ceramics was 340 Ah/kg at a C/20 rate for 1.5-4.2 V cutoff ranges. It is 10% higher than the capacity of the glass cathode. Moreover, the charge-discharge performance of the glass-ceramics cathode showed good cycleability similar to that of the glass. The glass-ceramics had a 83% capacity retention after 40 cycles. These results show that glass-ceramics is a potential candidate for lithium-ion cathode materials.

Different ferroelectric thin films and their related Metal-Semiconductor-Insulator-Metal (MSIM) structures include zinc oxide (ZnO) are studied, which can be utilized in back-gated ferroelectric field-effect transistors (FETs). The most ideal zinc oxide (ZnO) thin film prepared by sol-gel method are obtained under the pyrolysis temperature of 400°C and the annealing temperature of 600°C. The asymmetric or symmetric current-voltage characteristics of the heterostructures with ZnO are exhibited depending on different ferroelectric materials in them. The curves of drain current versus gate voltage for MSIM-structure FETs are investigated, in which obvious counterclockwise loops and a drain current switching ratio up to two orders of magnitude ate observed due to the modulation effect of remnant polarization on the channel resistance. The results also indicate the positive influences of impurity atom substitution in bismuth ferrite thin film for the MSIM-structure FETs.

We explored the use of galvanostatic electrochemical deposition of Pt for cost-effective fabrication of interconnects in flexible implantable bio-medical devices. Initial studies were done on coupons diced from 200 mm Si wafers coated with PVD TiN. Based on the physical and chemical properties of the electrodeposited Pt films, optimal conditions were chosen for through-mask plating of centimeters long Pt lines on flexible, medical grade, releasable polyimide layers. Possibility for further up-scaling was considered with special emphasis on high throughput manufacturing of Pt interconnects with good adhesion to TiN/flexible substrates, low impurity content and resistivity, and acceptable roughness and uniformity.

A statistically sound procedure for the unambiguous identification of the underlying Bravais lattice of an image of a 2D periodic array of objects is described. Our Bravais lattice detection procedure is independent of which type of microscope has been utilized for the recording of the image data. It is particularly useful for the correction of Scanning Tunneling Microscope (STM) images that suffer from a blunt scanning probe tip artifact, i.e. simultaneously recording multiple mini-tips. The unambiguous detection of the type of translation symmetry presents a first step towards making objective decisions about which plane symmetry a 2D periodic image is best modeled by. Such decisions are important for the application of Crystallographic Image Processing (CIP) techniques to images from Scanning Probe Microscopes (SPMs).

CZTS monograin powder samples were synthesized in CdI2 as flux material. The obtained materials were analysed by EDX, SEM, and Raman methods. It was found that Cd from flux was incorporated into the formed compound leading to the formation of solid solution Cu2Zn1-xCdxSnS4. The content of Cd in the compound was studied in the dependence of synthesis temperature and time. It was found that Cd content in the formed Cu2Zn1-xCdxSnS4 did not depend on synthesis duration at constant temperature and increased with temperature. The activation energy of the Cd incorporation process was estimated as 17.5 ± 2 kJ/mol.

Currently, large efforts are going on to scale up PZT thin film processes for large volume MEMS fabrication. It is critical to complete the scaling up with optimized film properties. In this work we report about microstructural control and piezoelectric properties of RF magnetron sputtered PZT (Pb(Zrx,Ti1−x)O3) thin films. The former is a prerequisite to achieve good properties homogeneously on the entire wafer, and with a good repeatability. We focus on the use of a commercial tool capable to reach a deposition rate of 1nm/sec with a thickness uniformity better than +/-3%. We show particularly how the texture can be chosen between (100) and (111) orientation upon tuning the thickness of a very thin TiO2 seed layer on fully passivated Pt electrodes. The surface morphology as resulting from the various grain shapes is strongly influenced by the self-bias established on the substrate, and by the growth temperature. PZT films with compact grain structure and flat surface reached a transverse piezoelectric coefficient e 31,f of -23±1 C/m2 in the actuator mode (converse piezoelectric effect) and a dielectric strength of 0.5MV/cm. Both are remarkable values for un-doped, pure PZT thin films.

Compacted bentonite barrier in radioactive waste repositories is expected to prevent radionuclide migration, due to its high sorption capability for many radionuclides. This study analyses whether the addition of Al2O3 nanoparticles (NPs) enhances the sorption properties of bentonite. The study was carried out with 109Cd, highly pollutant heavy metal and divalent fission product. Sorption experiments were conducted in NaClO4 at different ionic strengths (5·10-4 to 10-1 M) and pH (2 to 10), using mixtures of sodium homoionised bentonite and Al2O3 in different proportions.

It has been probed that addition of Al2O3 NPs to bentonite enhances Cd sorption at pH higher than 6. The effect of Al2O3 NPs addition on the surface properties of bentonite colloids was also analyzed by measuring particle size and surface charge in all studied systems.

Stimuli-responsive materials are capable of reversibly altering their properties depending on the environmental conditions or external stimuli. External stimuli typically include thermal, pH, electric fields, optical, magnetic fields, mechanical forces and chemical interactions. There are many instances in nature where responsive surfaces have been observed. Temperature is the most widely used stimulus in environmentally responsive polymer systems. The change of temperature is not only relatively easy to control, but also easily applicable both in vitro and in vivo. Temperature responsive polymers exhibit a phase transition at a certain temperature, which causes a sudden change in the solvation state. Polymers that become insoluble upon heating have a so-called lower critical solution temperature (LCST). One example of these polymers is poly (N-isopropyl acrylamide), which shows LCST at about 32 °C, close to the physiological temperature. In this study, we report the developing of novel polyampholytes which shows thermo-, salt-responsive liquid-liquid phase separation in aqueous solution.

Electrochromic Windows(ECWs) have the potential to save energy through dynamic control of light and solar energy entering a room (via solar heat gain coefficient control). ECWs have been developed as an optical shutter in airplane, building and automobile applications. An ECW is composed of three components, a working electrode based on electrochromic materials, a counter electrode based on ion storage materials and the electrolyte as an ionic conducting layer. Organic ECWs have been gaining popularity due to easy and cost effective manufacturing, availability of wide range of colors, high optical contrast and flexibility in design. However there are challenges in commercialization and application of organic ECWs. The application of ECWs as a sunroof in automobiles demands operation in harsh environment conditions like elevated temperature. Consequently the University of Washington, Center for Intelligent Materials and Systems has been developing a heat resistant organic ECW that can be operated at elevated temperatures maintaining high optical contrast, fast switching speed, optical color memory and electrochemical stability. The proposed design is an ECW based on poly (3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine),PPRODOT-Me2 as a working electrode, V2O5-TiO2 composite materials as a counter electrode and poly(ethylene imine) based electrolyte. The ionic conductivity of the electrolyte was calculated through complex impedance method and temperature dependence of the electrolyte was determined using environment test chamber to control a temperature range of 15 to 80o Celsius for 100 hours. A 76 × 76 mm2 ECW was developed and the optical transmittance change was observed by Chronoamperomerty and Time course measurement. The electrochemical stability of the window was monitored using cyclic voltammetry. The developed electrochromic window showed good optical contrast, electrochemical stability and fast response time after testing at elevated temperatures for 100 hours.

Cs-137 was accidentally spilled in an industrial waste repository located in a salt marsh in southern Spain, and a permeable reactive barrier was proposed to retain it. Cs adsorption properties of different natural clayey materials were analyzed. The salt marsh waters show high salinity and high chemical variability, therefore Cs adsorption was also analyzed in the presence of competitive ions, especially K+ and NH4 +.

Cs adsorption was non-linear in all the analyzed materials, indicating more than one adsorption sites with different selectivity. It was shown that in mixed clay systems with illite, montmorillonite and kaolinite, the presence of illite favors Cs retention at low and medium Cs loadings and montmorillonite at high Cs loadings. In the presence of illite and montmorillonite, kaolinite plays almost no role in Cs retention. The presence of K+ and NH4 + significantly hinders cesium adsorption.

The very synthesis of functional microparticles is generally deemed the most necessary, but obviously not the only step in successful product development. The behavior of obtained microparticles has to be tested in environments resembling the end use conditions to ensure the desired functionality. During the testing, various problems concerning particles behavior can arise, e.g. unwanted adhesion (before the successful delivering of particles to the region of interest, they will adhere somewhere else, thus hindering the delivery of transported substance), insufficient adhesion (in cases, when the particle adhesion is desired, e.g. specific adhesion for targeted delivery, the end amount of adhered particles might not be sufficient for reaching the expected concentration of released substance, meaning adhesion is not strong enough under given conditions) or particle breakage (some particles are of more fragile structure, which can result in condition limitations, in which they can exist without damage). Furthermore, regarding specific adhesion, the demonstration of such particle functionality should also be performed before testing on living organisms, preferably in conditions resembling the end use.

The self-organization of functional proteins directly onto solid materials is attractive to a wide range of biomaterials and systems that need to accommodate a biological recognition element. In such systems, inorganic binding peptides may be an essential component due to their high affinity and selective binding features onto different types of solid surfaces. This study demonstrates a peptide-enabled self-assembly technique for designing well-defined protein arrays over a metal surface. To illustrate this concept, we designed a fusion protein that simultaneously displays a red fluorescence protein (DsRed-monomer), which is highly selective for copper ions, and a gold binding peptide AuBP. The peptide tag, AuBP, self-directs the organization of DsRed-monomer protein onto a gold surface and forms arrays built upon an efficient control of the organic/inorganic interface at the molecular level. The peptide-assisted design offers a modular approach for fabrication of fluorescent-based protein arrays with copper ion sensing ability.

The electrochemical effects of embedding Cu nanoparticles in carbonized wood supercapacitor electrodes have been investigated. The nanoparticles were embedded using a solution method. Subsequent X-ray diffraction (XRD) and scanning electron microscopy (SEM) results showed that the Cu nanoparticles were anchored uniformly on the surface and deep within the pores of the electrode. Cyclic voltammetry measurements showed that the electrode has typical pseudocapacitive behavior, with two pairs of redox reaction peaks. The charge-discharge cycling also indicated that the redox charge transformation was a reversible process. An ultra-high specific capacitance of 888 F/g and an energy density of 123 Wh/kg were observed for the Cu loaded electrodes, as compared to the pure carbonized wood electrodes, which had a specific capacitance of 282 F/g and an energy density of 39 Wh/kg. Furthermore, both the carbonized wood and Cu loaded electrodes exhibited excellent long cycle abilities with at least 95% of the specific capacitance retained after 2000 cycles. These remarkable results demonstrate the potential for using Cu nanoparticle loaded carbonized wood as a high performance and environmentally friendly supercapacitor electrode material.

A study of the fluid flow in a mixing device proposed to dissolve alloying elements in iron baths is performed through a mathematical model in order to predict the best operating conditions for a proper melting/dissolution of solid alloying particles. The mathematical model consists in the mass and momentum conservation equations (continuity and Turbulent Navier-Stokes equations), and the standard two k-epsilon turbulence model. The model is numerically solved in transient regime with the Volume of Fluid algorithm (VOF) to calculate the vortex shape. VOF is built-in the CFD (Computational Fluid Dynamics) software ANSYS FLUENT 14. A flow of metal enters tangentially in the mixing chamber of the proposed mixing device (taken from an open patent) to generate a vortex. The shape and height of the vortex reached in this chamber depends on several design variables, but in this work only the presence or absence of a barrier in the device is analyzed. Results are obtained on the vortex sizes and shapes, liquid flow patterns, turbulent structure, residence times of the particles of alloying elements added to the melt and mixing times (Residence time distribution curves) of two devices: one with a barrier and the other without this barrier. It is found that the presence of the barrier in the device increases turbulence, destroys the vortex, decreases the residence time of the particles, and decreases the volume of fluid in the device. Most of the features of the barrier are detrimental for mixing and inhibits melting/dissolution of the alloying elements. Then, it is suggested a device without the presence of barrier for better performance.