Droplet interface bilayers (DIBs) are formed using brain total lipid extract (BTLE) to create a synthetic bilayer whose lipid composition mimics that of neural cells. The electrical properties of BTLE DIBs, specifically membrane resistance, capacitance, and rupture potential, are determined and compared to the properties of bilayers formed using DPhPC, the most common lipid within the growing DIB field. There is no significant difference in the resistance or rupture potential of BTLE and DPhPC bilayers, for instance with average nominal resistance over 200 GΩ and rupture potential around 200 mV. In electrical measurements with either DPhPC or BTLE bilayers, applied voltages of up to ±150 mV yield low levels of leakage current. Upon interaction with the pore-forming amyloid-beta (Aβ) peptide, both bilayers display sudden significant voltage-dependent increases in conductance with characteristic threshold voltages well below 150 mV. Discrete single-channel type events are observed in the case of Aβ-BTLE whereas disordered fluctuating conductance is observed with Aβ-DPhPC. Circular dichroism is measured for Aβ incubated with BTLE and DPhPC liposomes, as well as pure Aβ, at a range of temperatures over a period of several weeks. Changes in secondary structure of liposome-bound and pure Aβ are significantly affected by both lipid type and temperature. A key finding includes the 100% conversion of Aβ to alpha-helical confirmation within 24 hours when incubated with liposomes (of either type) at physiologically relevant 37°C. The 100% alpha-helical Aβ is maintained for up to 2 weeks at 37°C when incubated with liposomes, although other structures begin to emerge after the 14 day mark. Between 14-31 days after reconstitution, Aβ incubated at 37C with BTLE bilayers displays longer lasting alpha-helical content than DPhPC. At the same temperature, pure Aβ is 100% alpha helical only at the 1 day mark with apparent restructuring from day 2 through day 31. Refrigerated Ab samples do not display 100% alpha-helical structure across the entire 31 day testing period. The differences observed between BTLE and DPhPC in both electrophysiological and spectroscopic experiments may be a result of phase separations or other variations in membrane fluidity that result from the use of a homogeneous total lipid extract. Time and temperature play essential roles in the aggregation and restructuring of potentially toxic Aβ oligomers, and there is motivation for further efforts to elicit the mechanistic differences in interactions of Ab with BTLE compared to DPhPC.

Our team is developing an optically-based smart monitoring system prototype targeting batteries for advanced battery applications such as hybrid and electric vehicles (EVs). The system concept envisions fiber optic (FO) sensors embedded within Lithium (Li)-ion batteries to measure parameters indicative of cell state in conjunction with our low-cost, compact optical wavelength-shift detection technology and intelligent algorithms to enable effective real-time performance management and optimized battery design. Towards these goals, we have successfully made functional prototypes of Li-ion pouch cells with FO sensors embedded within the electrode stack during cell fabrication. The strong, interesting signals from these FO sensors obtained over charge-discharge cycles offer valuable information and features to enable more accurate cell state-of-charge (SOC) and state-of-health (SOH) estimation, and better understand cell electrochemical and aging processes. This paper presents initial results from these prototype cells and compares the results from internal FO signals to earlier results reported by our team on purely external configurations where the FO sensors were attached to the cell skin.

We report the preparation of nanomasks for silicon plasma etching, which is not based on full top-down approaches such as conventional lithographic process. We used laterally phase separated polymers thin films (30 to 100 nm thick) obtained from immiscible polymer blends of poly(styrene) PS and poly(lactide) PLA, PS being the major component, spin-coated onto silicon substrates. Despite the high incompatibility of the two polymers, submicronic domains were obtained in the film. The selective extraction of the minor component (PLA) led to the formation of a perforated layer of PS at the top of the silicon substrate, and was used as a mask for the selective etching of the silicon. For that purpose, we used a cryogenic etching process where the silicon substrate was cooled at a cryogenic temperature (∼ -120°C) and exposed to a monocyclic SF6/O2 plasma. It was possible to etch anisotropic profiles with vertical sidewalls and minimal defects. Etched feature with an aspect ratio of 7 were obtained in these conditions. We determined that the selectivity of etching (Si/PS) was 11:1, with a silicon etching rate of 0.8 µm/min. The selectivity of these masks was further increased when using the inorganic replicas of the polymer template (50:1) or with chemical modifications of the PS by RuO4 (80:1), allowing for increased aspect ratio etched features (up to 20 in the latter case). Optimized etching processes (such as STiGer process) were also used in order to improve the reproducibility and robustness of the method.

The potential of Raman and UV-Vis diagnostics for spatially-resolved and in situ diagnostics of lithium-ion batteries is demonstrated. Regarding the use of in situ Raman diagnostics focus is put on LiCoO2 electrode materials, which were investigated in detail as composites of LiCoO2 with binder and conductive additives. The potential of in situ UV-Vis analysis is illustrated for carbon-based materials showing significant absorption changes during electrochemical cycling due to lithium de-/intercalation.

Boron nitride nanotubes (BNNTs), an analogue of carbon nanotube (CNT) is one of the most used non-metallic materials in high technology applications related to thin film fabrications. Taking advantage of their unique properties such as electrically non-conductive, thermally conductive, and high hardness, it has been used in high-temperature electronic devices, multifunctional aerospace materials, and structures and electric and aerospace systems. The main goal of this project was to use BNNTs in the fabrication of nano epoxycomposites to enhance their thermal and mechanical properties to use it for applications in aerospace constituents. In order to accomplish this goal, BNNTs were functionalized with isopherone diisocyante (IPDC). Surface analysis techniques were employed to ensure the modification BNNTs and study the interface of the reinforced composites before and after the modification. Mechanical and thermal conductivity testing was performed in order to understand the quality of the composites. Three different nanocomposites were accomplished with hBN and BNNTs using two different epoxy polymers and three curing agents. The systems EPON 862/Curing Agent W/ (hBN or BNNTs) have Tgs and tan deltas higher compared with those fabricated at the same conditions without nanoparticles. The fabricated BN composites showed improved physical properties due to their particle dispersion and boron nitrite intermolecular interactions with the epoxy polymer.

The aim of this preliminary study was to adapt Layer-by-Layer (LbL) assembly to fabricate nanocomposite coatings onto open-cell porous structures, enabling customization of mechanical properties and porosity to obtain materials suitable for bone tissue scaffold applications. LbL assembly is a well-established method for fabricating multilayer films with nanometre scale precision over thickness that is based on electrostatic attractions and involves the adsorption of oppositely charged electrolytes onto a substrate. Using LbL assembly, polymer-nanoclay composite coatings were deposited onto open-cell foam substrates. The elastic modulus of coated specimens in compression was improved from 0.078 MPa to 1.736 MPa. The results suggest that polymer-nanoclay coatings deposited via LbL assembly have the potential to improve mechanical properties of porous substrates and fabricate materials with mechanical properties comparable to that of a cancellous bone tissue upon deposition of a sufficient number of multilayers.

Efficacious resource harvesting constitutes new modes of conceptualizing the interactions of buildings with surrounding environmental conditions. The internal logic of a biotechnical paradigm in architectural design allows for the potential of fluid exchanges between medium and material to be realized with correlated metabolism. Such concepts avert existing mechanical paradigms based upon linear conservation of energy processes and approach entropic integrated design interactions of nonlinear dynamical processes. Through a physiological analogy that informs architectural anatomy, the genetic code of hydrogels embeds emergent morphological responses to discrete interactions with environmental phenomena. In contrast to the static hard tissue of the skeletal system, viscoelastic soft tissue provides significant environmental impact by means of integrating spatiotemporal adaptation in building systems.

This framework provides an interscalar perspective for integrating biopolymeric membranes within building-envelope systems and informs the microstate design of the polymer chains for optimized mechanical performance. Hydrogels are a translucent three-dimensional water-swollen polymer, which exhibit mechanical work upon interaction with water vapor. In effect, this interaction provides for a variant index of refraction, a variant heat capacitance, and a physical shift in surface morphology. Characteristic changes in material thermal and mechanical properties parallel diurnal climate profiles for circadian biorhythmic membrane designs. The macrostates of temperature, pressure, and volume reciprocally inform the potential microscopic properties, including position and velocity of each molecule within the material system. The viscoelastic molecular entropy (Maxwell model) of hydrogels is established as a fundamental basis for situating a dynamic material logic influencing a high efficacy architectural physiology. The Maxwell model is translated as an algorithmic framework for mechanical control through tetra-functional polymer chain development of biopolymeric hydrogels. In contrast to polyacrylamide hydrogels, the chemistry of biopolymeric polysaccharide hydrogels is well suited for renewable sourcing and down cycling to achieve sustainable material life cycles. However, these biopolymers do not inherently exhibit robust structural properties necessary for influencing morphological shifts of the membranes for intelligent passive design strategies such as self-actuating ventilation apertures or self-shading surface geometries. The research encompassed in this work engages the development of a more acute framework for the trajectory of biopolymeric hydrogel dynamics based upon a necessity for controlled morphological modulations in response to specific environmental conditions.

A novel approach for synthesis of few layer graphene films on SiC has been developed which uses halogen based inductively coupled-reactive ion etching (ICP-RIE) and rapid thermal annealing (RTA) in atmospheric pressure argon. These films have been characterized using x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Surface characterization by XPS reveals the presence of defects similar to those observed for graphene oxide (GO) but at a much lower levels that those observed for GO. As in the case for GO, the defect density could be further reduced by chemical methods which improved carbon to defect ratio based on XPS analyses. Raman spectroscopy showed the presence of D, G and 2D peaks at 1330 cm-1, 1599 cm-1 and 2671 cm-1, respectively, which is comparable with similar graphene films formed by thermal annealing of SiC. The full widths at half max (FWHM) for these peaks was, however, comparable to those observed for GO. Electrical characterization of these graphene films using collinear four point probe measurements showed the electrical resistivity of these films is consistent with the observed values for few layer exfoliated graphene. Gas sensor structures were fabricated using lithography free methods, and initial gas response studies were performed for H2.

Process-induced defects in electroplated Au interconnect metallization on GaAs devices were detected during the course of reliability testing. Abnormally high lognormal sigma values (σ > 0.7) indicated the existence of a bi-modal failure mechanism. A distinct early lifetime failure mode was observed along with the intrinsic electromigration metallization wear-out failure mode. Physical characterization of the electroplated Au film revealed as-deposited nanoscale voids. Elimination of these voids through process improvement as well as suggested mechanisms for the early failures are discussed.

Thermoelectric CuIn1-xAlxTe2 compounds (x=0, 0.05, 0.1, 0.15, 0.50) have been synthesized by solid state reaction followed by spark plasma sintering. The influence of Al substitution on electrical and thermal transport properties has been investigated in the CuInTe2 compounds. It was found that the Seebeck coefficient and electrical conductivity is reduced by isovalent replacement of In with Al. Our first principle calculation indicates Al substitution leads to the widen band gap, the reduction in the number of degeneracy of valence band and the effective mass. Furthermore, a large reduction in thermal conductivity is achieved through the enhanced phonon scattering via point defect as well as the nano-sized particles observed between grain boundaries and on the grain surface. In spite of the reduced charge transport properties, an improved figure-of- merit ZT is achieved, reaching 0.8 at 800 K, 33% higher in comparison to the pure CuInTe2 compound.

Ca2MnO4 nanoparticles were prepared by the Pechini method and acid treated to extract Ca2+ ions. Structural, morphological and spectroscopic analyses by XRD, SEM/EDX, TEM/EDS and Raman revealed the formation of an amorphous outer layer at the particles surface with a preserved inner crystalline bulk. Thanks to the outer layer, which is electrochemically active, the acid-treated compounds showed capacity up to 150 Ah/kg. The crystalline bulk improved cycling stability, allowing reaching capacity retention up to 70% after 30 cycles.

We report on the formation of photoactive hybrid structures based on multilayer graphene nanobelts and CdSe/ZnS quantum dots (QDs) on Pt microelectrodes. We have found that heat treatment in mild conditions enhances rate of electrical photoresponse of the hybrid structures due to elimination of long-lived charge traps. We also show that the electrical photoresponse polarity depends on the energy level structure of the QDs.

In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous-crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor/acceptor). The second part is carried out by numerically solving the steady-state Pauli master equation. By taking the energetic disorder of each phase, their energy offset and domain morphology into consideration, we show that the carrier mobility can have a significant different behavior when compared to a one-phase system. When the energy offset is non-zero, we show that the mobility electric field dependence switches from negative to positive at a threshold field proportional to the energy offset. Additionally, the influence of morphology, through the domain size and the interfacial roughness parameters, on the transport was also investigated.

Electrochemical performances of a prototype Lithium-Bromine battery (LBB) employing a solid electrolyte was investigated. It showed the discharge capacity of c.a. 147 mAh/(g-LiBr) for the first cycle, which decreased with repeating charge/discharge cycles. The capacity fading was mainly due to increase of the interfacial resistance between an aqueous active material solution and a solid electrolyte. From the results of symmetric cells and structural analysis of the surface of the solid electrolyte immersed in Br2 solutions, it was suggested that a Li+-depletion layer was formed on the surface of the solid electrolyte by contact with bromine.

In a future Swedish deep repository for spent nuclear fuel, irradiated control rods from PWR nuclear reactors are planned to be stored together with the spent fuel. The control rod absorber consists of an 80% Ag, 5% Cd, 15% In alloy with a steel cladding. Upon in-reactor irradiation 108Ag is produced by neutron capture. Release of 108Ag has been identified as a potential source term for release of radioactive substances from the deep repository.

Under reducing deep repository conditions, the Ag corrosion rate is however expected to be low which would imply that the release rate of 108Ag should be low under these conditions. The aim of this study is to investigate the dissolution of PWR control rod absorber material under conditions relevant to a future deep repository for spent nuclear fuel. The experiments include tests using irradiated control rod absorber material from Ringhals 2, Sweden. Furthermore, un-irradiated control rod absorber alloy has been tested for comparison. The experiments indicate that the release of Ag from the alloy when exposed to water is strongly dependent on the redox conditions. Under aerated conditions Ag is released at a significant rate whereas no release could be measured after 133 days during leaching under H2.

We report on electrical conductivity and noise measurements made on p-type hydrogenated amorphous silicon (a-Si:H) thin films prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD). The temperature dependent electrical conductivity can be described by the Mott Variable Range Hopping mechanism. The noise at temperatures lower than ∼ 400K is dominated by a 1/f component which follows the Hooge model and correlates with the Mott conductivity. At high temperatures there is an appreciable G-R noise component.

A completely solid state dye sensitized solar cell (DSSSC) is proposed in which chemically robust phthalocyanine (Pc) sensitizers, F16ZnPc and F40ZnPc, are sandwiched between n-TiO2 and p-NiO. While the energy conversion efficiencies of conventional Grätzel cells are continually increasing, the DSSSC design effectively solves the long term stability issues of the volatile liquid electrolyte. Through analysis of the electronic structure of the Pc|semiconductor systems, the free energy associated with hole injection into the valence band of NiO upon photoexcitation of the sensitizer and electron injection into the conduction band of TiO2 from the reduced form of the sensitizer as well as the competing charge recombination processes are calculated. Thermodynamically, the charge injection processes are found to be favored over the undesired charge recombination processes. These findings suggest promising energy conversion for the NiO|Pc|TiO2 DSSSC.

Designing bioactive materials, with controlled metal ion release, exerting significant bioactivity and associated low toxicity for humans, is nowadays one of the most important challenges for the scientific community. In this work, we propose a new material combining the well-known antimicrobial properties of copper nanoparticles (CuNPs) with those of bioactive chitosan (CS), a cheap natural polymer widely exploited for its biodegradability and nontoxicity. Here, we used ultrafast femtosecond laser pulses to finely fragment, via laser ablation, a Cu solid target immersed into aqueous CS solutions. Homogeneously dispersed copper-chitosan (Cu-CS) colloids were obtained by tuning the Cu/CS molar ratios, according to the initial chitosan concentration, as well as other experimental parameters. Cu-CS colloids were characterized by several techniques, like UV-Vis and X-ray Photoelectron spectroscopies (XPS). Transmission Electron Microscopy (TEM) was used to morphologically characterize the novel nanocomposites.