bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation, Characterization, Protein Resistance, and Reactivity of Cl3Si(CH2)11(OCH2CH2)3OH Self-Assembled Monolayers
Authors: Seong Jiehyun , Lee Seok-Won , Laibinis Paul E. 
Published: June 2019

AbstractWe report a method for generating tri(ethylene glycol)-terminated-n-alkyltrichlorosiloxane monolayers on SiO2 surfaces. These chemisorbed films, with a thickess of ∼2-3 nm, provide an oligo(ethylene glycol) surface that reduces the nonspecific adsorption of proteins and hydroxyl attachment sites for covalently immobilizing biomolecules to the substrate. These mono-molecular films were formed by adsorbing an acetoxy-tri(ethylene glycol)-terminated n-alkyltrichlorosilane, CH3(C=O)O(CH2CH2O)3(CH2)11SiCl3, onto glass and Si/SiO2 substrates, where the terminal acetate provided a protecting group for the hydroxyl functionality during self-assembly of the film. After formation of the monolayer, the acetate functionality was reduced chemically to form films exposing a covalently attached -(OCH2CH2)3OH terminus at a density of ∼3[.dotmath]1014 molecules/cm2. Protein adsorption studies verified that the films exhibited notable resistances against the non-specific adsorption of various proteins. Chemical modification of the -(OCH2CH2)3OH surface with protein A provided a non-adsorbing surface for selective immobilization of immunoglobulins.
Effects of Ionic Flow and Amelogenins on the Lengthwise Growth of Octacalcium Phosphate Crystals in a Model System of Tooth Enamel Formation
Authors: Iijima M. , Moriwaki Y. , Wen H.B. , Takagi T. , Fincham A.G. , Moradian-Oldak J. 
Published: June 2019

AbstractThis paper briefly reviews our recent studies, which aimed to investigate the effects of 1) the Ca2+and PO43-ions flow and 2) amelogenins on the lengthwise growth of octacalcium phosphate (OCP), which is a potent precursor of enamel apatite crystal. OCP crystals were grown at 37°C in a dual membrane system under various amount of ionic inflow into a reaction space, using 1) 5-30mM Ca and PO4solutions as ionic sources and 2) extracted bovine amelogenin and recombinant murine amelogenins (rM179, rM166). With an increase in the amount of Ca2+and/or PO43-ions flow, the length of OCP crystal increased, while the width decreased. As a result, the length to width (L/W) ratio of crystal changed from 3 to 95, while the width to thickness (W/T) ratio from 32 to 9. The effect of amelogenins was unique, regardless of the type of amelogenins: Rod-like and prism-like OCP crystals with large L/W (61∼107) and small W/T (1.3∼2.2) ratios were formed in 10% amelogenin gels. In contrast, characteristic ribbon-like OCP crystals grew without protein and with gelatin, albumin, polyacrylamide gel and agarose gel. Specific interaction of amelogenins with OCP crystal was ascribed to the self-assembly property of amelogenin molecules and their hydrophobic nature. It was suggested that ionic flow and amelogenins play some critical roles in the elongated growth of enamel crystals.
Spatio-Temporal Patterns in Ferritin Crystal Growth
Authors: Gliko Olga , Vekilov Peter G. 
Published: June 2019

AbstractWe investigate the unsteady kinetics and the formation of spatio-temporal patterns during the ferritin crystal growth, which is controlled by the rate of supply of material. For this, we apply a novel phase-shifting interferometry technique. We find that the growth rate and local slope fluctuate by up to 100% of their average values as a result of step bunching. The fluctuation amplitudes decrease with higher supersaturation and larger crystal size, as well as with increasing distance from the step sources. Since these are parameters that govern the protein supply field, we conclude that fluctuations are rooted in the coupling of the interfacial processes of growth to the bulk transport in the solution. Analysis of the step velocity dependence on local slope indicates a very weak interaction between the steps. Hence, in transport-controlled systems with non-interacting or weakly interacting steps the step bunches decay and step train tends towards its stable, equidistant state.
Tissue Engineering of Fibroblast Constructs and Anisotropic Collagen Gels
Authors: Calve Sarah , Arruda Ellen , Dennis Robert , Grosh Karl , Pasyk Krystyna 
Published: June 2019

AbstractThe creation of anin vitrofunctional tendon construct will enable testing of the influence of mechanics and nutrients on the development and remodeling of tendon under known controlled stimuli which is difficult to achievein vivo. Tendon constructs were engineeredin vitrovia stress-mediated self organization of fibroblasts and ECM on a laminin coated elastomer substrate. Varying the laminin density and the amount of fetal bovine serum on the substrate affected the ability of tendon fibroblasts to form a confluent cell layer and the time to layer delamination. Understanding the factors that promote self-assembly of tendon constructs will enable their combination with already developedin vitromuscle constructs.
Synthesis of biocompatible surfaces by different techniques
Authors: Garreta E. , Fernández T. , Borrós S. , Esteve J. , Colominas C. , Kempf L. 
Published: June 2019

AbstractIn the present work, a sol-gel method of HA synthesis has been developed using different calcium and phosphorous precursors. In order to make a porous scaffold, HA aerogel formation and HA liofilization processes have been studied. The liofilized HA and the HA aerogels have been characterized by SEM-EDX and X-Ray difraction. Finally, so as to improve the biocompatibility and the bioadhesion of the HA scaffolds, different plasma polymerization techniques have been studied. Acrylic acid has been polymerized using plasma polymerization with a radiofrequency source. Different radiofrequency source powers and reactor designs have been tryed. The kinetics of the thin film growth have been studied and the optimal polymerization conditions have been established. Polymeric layers have been characterized by IR and XPS.
Ac Impedance Spectroscopy Study of Modified Proton-Exchange Membrane Nanocomposites
Authors: Damay Françoise , Klein Lisa C. 
Published: June 2019

AbstractThe dielectric and electrical behaviors of a NafionTM membrane, a NafionTM/7SiO2-2P2O5-ZrO2 gel composite, and a NafionTM/ZrP particle composite were investigated using ac impedance spectroscopy at different relative humidities and temperatures. Only NafionTM/7SiO2-2P2O5-ZrO2 showed a slightly higher conductivity than NafionTM at high temperature. For NafionTM/ZrP, proton mobility was significantly lower, particularly at high relative humidity. The results suggest that improvement in fuel cell performance, previously measured on composite membranes, does not merely result from increased hydrophilic properties.
Polymer Nanocomposite Foams Prepared by Supercritical Fluid Foaming Technology
Authors: Lee L. James , Zeng Changchun , Han Xiangmin , Tomasko David L. , Koelling Kurt W. 
Published: June 2019

AbstractPolystyrene (PS) clay nanocomposites were synthesized and used to prepare foams in both batch and continuous extrusion process. It was found that the addition of a small amount of clay could greatly reduce cell size and increase cell density. Once exfoliated, the nanocomposite foam exhibits the highest cell density and the smallest cell size at the same particle concentration. Exfoliated microcellular nanocomposite foams with good surface quality was successfully produced using supercritical carbon dioxide.
Carbon Nanofiber Reinforced Composites for Enhanced Conductivity, Strength, and Tensile Modulus
Authors: Tibbetts Gary G. , Finegan Ioana C. , Kwag Choongyong 
Published: June 2019

AbstractCarbon nanofibers of diameter 200 nm may be used as an additive to thermoplastics for applications requiring electrical conductivity and enhanced mechanical properties. The electrical properties of nanofiber in thermoplastics such as nylon and polypropylene and are very attractive compared with those provided by other conventional conducting additives. Because of the low diameter of the nanofibers used, the onset of electrical conductivity (percolation threshold) can be below 1 volume %. Because of the highly conductive nature of the fibers, particularly after a graphitization step, the composites can reach resistivities as low as 0.15 Ohm cm. These conducting composites may be used for applications such as radio frequency interference shielding, primerless electrostatic painting, and static discharge. In order to make composites having excellent mechanical properties, good adhesion between fiber and matrix is essential. Carbon nanofiber-matrix adhesion was studied after surface treating the fibers using a variety of methods. Among as-grown fibers, those produced with longer gas phase feedstock residence times in the fiber growth reactor were less graphitic but adhered to a polypropylene matrix better, giving improved tensile strength and modulus Two chemical treatments were found to be somewhat effective in increasing tensile strength, but both decreased the modulus.. A modest degree of oxidation was also found to increase adhesion to the matrix and increase composite tensile strength, while extended oxidation attacked the fibers sufficiently to decrease composite properties.
The Formation of Ordered Nanoporous Structure with Controlled Micelle Size
Authors: Chang Jeongho , Shin Yongsoon , Wang Li-Qiong , Exarhos Gregory J. 
Published: June 2019

AbstractSelected MPEG-b-PDLLA block copolymers have been synthesized with systematic variation of the chain lengths of the resident hydrophilic and hydrophobic blocks. The size and shape of the micelles that spontaneously form in solution are then controlled by the characteristics of the copolymer template. Formation of nanoporous silica at room temperature with short-preparation time is demonstrated and silica-containing materials evolve with uniform pore shape and wall structure. The formation mechanism of these nanoporous structures obtained by controlling the micelle size has been confirmed using both liquid and solid state 13C and 29Si NMR techniques.
Nanocomposite Films derived from Alkoxysilane Terminated Amide Acid Oligomers and Carbon Nanotubes
Authors: Smith Joseph G. , Connell John W. , Lillehei Peter , Watson Kent A. , Thompson Craig M. 
Published: June 2019

AbstractLow color, space environmentally stable, polymeric materials with sufficient electrical conductivity for static charge dissipation are of interest for potential applications on Gossamer spacecraft. One method of imparting electrical conductivity while maintaining optical clarity is through the use of single wall carbon nanotubes (SWNTs). Both theory and research on SWNTs have shown them to be conductive. However, SWNTs are very difficult to uniformly disperse in a polymer. The approach described herein was to use oligomers endcapped with functional groups that could condense with functionalities present on purified, laser ablated SWNTs. Low color, radiation resistant amide acid oligomers endcapped with trialkoxysilane groups were combined with SWNTs. Since the SWNTs were purified by an oxidative process (nitric/sulfuric acid treatment), they have functionalities such as hydroxyl and carboxylic acid groups that can condense with the terminal alkoxysilane groups. After mixing at room temperature, the mixtures were used to cast films that were subsequently stage-cured up to 300°C for 1 hour in air. During this thermal treatment, imidization and condensation occurred. The chemistry, physical, and mechanical properties of the resulting nancomposite films will be presented.
Particle size and density control in magnetic polymer nanocomposites
Authors: Millan Angel , Palacio Fernando , Falqui Andrea , Etienne Snoeck , Serin Virginie 
Published: June 2019

AbstractMagnetic nanocomposites formed by metal oxide nanoparticles and organic polymers can be produced from a polymer-metal ion complex material by a soft thermal treatment. With only slight variations in the preparation procedure it is possible to obtain: 1) different iron oxide phases, e.g., hematite (antiferromagnetic), goethite and akaganeite (both canted antiferromagnets), and maghemite (ferrimagnetic); 2) nanocomposites with a different particle size, in a range from 2 nm to 20 nm; and 3) different particle density. In this contribution the preparation and properties of maghemite nanoparticles in polyvinyl pyridine composites are reported.
Three-DimensionalWafer Process Model for Nanotopography
Authors: Yoshida Takafumi 
Published: June 2019

AbstractThis paper proposes a three-dimensional wafer process model for nanotopography. This model allows us to predict the effect and behavior of nanotopography on the wafer processes especially for the wafer Mechanical/Chemical Lapping (MLP/CLP), wafer Single/Double Side Polishing (SSP/DSP) and device Chemical Mechanical Polishing (CMP).
A Model of Chemical Mechanical Polishing: The Role of Inhibitors
Authors: Paul Ed 
Published: June 2019

AbstractA previously presented model of CMP is extended to include the role of inhibitors. In CMP, a chemical reaction forms a surface film which is removed mechanically by abrasives. When inhibitor molecules bond to the surface film, the mechanical abrasion rate is reduced. The general model will be discussed, and then applied to W-CMP explaining differences in the reduction of polishing rates for different inhibitors.
Slurry Utilization Efficiency Studies in Chemical Mechanical Planarization
Authors: Philipossian Ara , Mitchell Erin 
Published: June 2019

AbstractThe residence time distribution of slurry in the pad-wafer interface was experimentally determined and used to calculate the slurry utilization efficiency (η) of the CMP process. Slurry utilization efficiency represents the percentage of slurry that actually participates in the polish by entering the region bounded between the wafer and the pad. Results show that η ranges from 2 to 22 percent, depending on operating conditions such as applied wafer pressure, relative pad wafer velocity, slurry flow rate and pad surface texture (i.e. type of pad grooving).
News from the M in CMP - Viscosity of CMP Slurries, a Constant?
Authors: Lortz W. , Menzel F. , Brandes R. , Klaessig F. , Knothe T. , Shibasaki T. 
Published: June 2019

AbstractIt is well known and accepted that the viscosity of CMP-slurries has an effect on polishing results. Even though the literature on rheology recognizes that viscosity is not always constant and the slurry can show non-Newtonian behavior or even dilatant effects, all calculations have been performed with constant viscosity.However, the “real” viscosity of a CMP-slurry during polishing can change significantly with shear rate.The typical equipment for viscosity measurement is based on a rotating cylinder or a plate. But even with a plate system it is only possible to reach a shear rate range up to 50,000 1/sec. A calculation of the shear rate between the wafer and the polishing pad is based on a relative velocity of 1 m/sec and a distance between the wafer and the pad of 20 μm; this correlates to a shear rate of 50,000 1/sec. If parts of the polishing pad come closer to the wafer or especially closer to the edge of structures on the wafer (for example 1 μm), the shear rate will increase locally to 1,000,000 1/sec.When the shear rate is high enough, viscosity depends mostly on hydrodynamic factors like viscosity of continuos phase, solids content, particle size, particle size distribution and shape of the particles.The shape of fumed metal oxides is controlled during the synthesis in the flame process. But the slurry-making process is also responsible for particle size distribution, shape of the particle and the high shear rate viscosity of the CMP-slurry.The high shear rate viscosity of different silica slurries in dependence from BET-surface area, used milling energy, concentration and preparation direction was measured in this investigation.
Atomistic Mechanisms Underlying Chemical Mechanical Planarization of Copper
Authors: Ye Y.Y. , Biswas R. , Bastawros A. , Chandra A. 
Published: June 2019

AbstractWith an aim to understanding the fundamental mechanisms underlying chemical mechanical planarization (CMP) of copper, we simulate the nanoscale polishing of a copper surface with molecular dynamics utilizing the embedded atom method. Mechanical abrasion produces rough planarized surfaces with a large chip in front of the abrasive particle, and dislocations in the bulk of the crystal. The addition of chemical dissolution leads to very smooth planarized copper surfaces and considerably smaller frictional forces that prevent the formation of bulk dislocations. This is a first step towards understanding the interplay between mechanistic material abrasion and chemical dissolution in chemical mechanical planarization of copper interconnects.
The Effect of Pad Properties on Planarity in a CMP Process
Authors: Kim Hoyoung , Park Dong-Woon , Hong Chang-Ki , Han Woo-Sung , Moon Joo-Tae 
Published: June 2019

AbstractThis study presents the effect of pad properties, such as elastic modulus and surface roughness, on planarity in a CMP process. A systematic method to measure planarization length, which represents the die-scale planarity in a quantitative manner, has been proposed. It has been shown that the planarization length is highly dependent on the bulk modulus of the pad. The effect of elastic modulus and roughness of the pad on dishing amount, which represents the feature-scale planarity, has been shown. Dishing amount is determined by the elastic modulus of the superficial layer of the pad, which is typically tens of microns thick, rather than by the bulk elastic modulus of the pad. A double layer pad model has been proposed based on the observed results, which can explain that the dishing amount is reduced by increasing elastic modulus of the pad superficial layer, or by decreasing the surface roughness of the pad.
Pad Degradation During CMP Process: Effect of Soak in Slurry and Water on Thermal and Mechanical Properties of the CMP Pads
Authors: Tregub A. , Ng G. , Moinpour M. 
Published: June 2019

AbstractSoak of polyurethane-based CMP pads in tungsten slurry and de-ionized water and its effect on retention of thermal and mechanical properties of the pads was studied using Dynamic Mechanical Analysis (DMA), Thermal Mechanical Analysis (TMA), Thermal Gravimetric Analysis (TGA), and Modulated Differential Scanning Calorimetry (MDSC). Simultaneous cross-linking and plastisizing due to soak were established using DMA and MDSC analysis. The stable operating temperature range and its dependence on soak time were determined using TMA analysis. Substantial difference in diffusion behavior of the “soft” and “hard” pads was discovered: diffusion into the hard pads followed Fickian law [1], while diffusion into the multi-layer soft pads was dominated by the fast filling of the highly porous pad surface with liquid.During a traditional CMP process, which involves application of polishing pads and slurry, the pad properties can be substantially and irreversibly changed as the result of slurry/rinse water absorption.The retention of the pad properties after exposure was monitored using such thermal and mechanical techniques, as Thermal Mechanical Analysis (TMA), Dynamical Mechanical Analysis (DMA), Modulated Differential Scanning Calorimetry (MDSC), Thermal Gravimetric Analysis (TGA).
Ta/low-κ CMP with Colloidal Silica Particles
Authors: Beaud Patrice , Bouvet Didier , Fazan Pierre , Jacquinot Eric , Aoki Hiroyuki , Aoki Tomoko 
Published: June 2019

AbstractLow-κ/Cu interconnect integration achievement is one of the key issues for the future sub-100 nm technologies. Nowadays, no definitive integration scheme has been reported. Low-κ integration is especially difficult because the trench/via etching and CMP processes can damage its properties. In the present work, we present results on different materials that could be used in such integration. We focused our study on the barrier (Ta/TaN) and on a low-κ material (dense and porous), that is a spin-on-dielectric (SOD) of the methylsilsesquioxane (MSQ) type. CMP slurries were made from monodisperse colloidal silica particles. In a first approach, the slurries compositions mainly differed by their pH and abrasive characteristics. The particle size ranged from 12 to 80 nm, with a pH varying between 2 and 11. The sensitivity of the Ta/TaN and low-κ removal rates will also be reported. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) of the different films were carried out in order to evaluate the impact of CMP on their surface quality. Measurements did not show any surface degradation or/and scratches, and no delamination has been observed. Post-CMP κ value measurements have been carried out to highlight possible damage on the low-ê dielectric materials.
Chemical-Mechanical Planarization of Copper: The Effect of Inhibitor and Complexing Agent
Authors: Luo Ying , Du Tianbao , Desai Vimal 
Published: June 2019

AbstractThe present investigation was focused on understanding of the oxidation, dissolution and modification of Cu surface in slurries at various pH using hydrogen peroxide as oxidizer, glycine as complexing agent and 3-amino-triazol (ATA) as inhibitor during Cu-CMP. The electrochemical process involved in the oxidative dissolution of copper was investigated by potentiodynamic polarization studies. Surface modification of copper was investigated using Xray photoelectron spectroscopy to understand the interaction of Cu-H2O2-glycine-ATA during CMP. In the absence of glycine and ATA, the copper removal rate is found to be high in a slurry with 5% H2O2 at pH 2, then it decreases with increasing pH and reaches the minimum at pH 6, it continuously increases at alkaline condition. In the presence of 0.01M glycine, the removal rate of copper decreases in acidic slurries while increases significantly in alkaline slurries. With the further addition of ATA, the copper removal rate was reduced. However, better surface planarity was obtained. The present investigation enhanced understanding of the mechanism of Cu CMP in the presence of oxidizer, complexing agent and inhibitor for formulation of a highly effective CMP-slurry.
Slurries for Copper Damascene Patterning: Similarities and Differences
Authors: Jindal A. , Rajagopalan G. , Gupta M. , Lu J.-Q. , Rose K. , Gutmann R.J. 
Published: June 2019

AbstractTwo first-step copper damascene slurries and one commercial second-step slurry are characterized in terms of their intrinsic properties and CMP performance. A prototype first-step slurry with high static etch rate (∼150 nm/min) yielded higher dishing in the copper lines (∼200 nm in 100 μm lines) compared to a commercial first-step slurry with negligible static etch rate. In both the cases, dishing in copper lines is observed to be a strong function of line width and radial position on the wafer. High static etch rate of the prototype slurry is believed to be responsible for the high dishing. Non-selective second-step polishing removes the liner layer while maintaining planarity.