An improved method for the measurement of power consumed in low pressure, radio frequency discharges is presented. The involves current and voltage waveforms outside reactor, determination discharge impedance network parasitics. measured are transformed to equivalent ones at powered electrode, by using an electrical circuit model stray cell, with experimentally determined components. A tunable shunt used minimizing displacement currents. contains elements which account also resistive losses...

The signal enhancement of an easy to fabricate, nanoporous alumina assisted surface plasmon resonance (SPR) sensor is investigated. It theoretically shown that the presence a thin (under 200nm) porous layer on top aluminum film supporting plasmons, may significantly increase (over one order magnitude) sensitivity SPR method in case where adsorption relatively small molecules probed. comparative experimental investigation self-assembled monolayer formation planar metal films and layers...

Abstract The formation process of n ‐alkane phosphonic acid CH 3 (CH 2 ) −1 PO(OH) ( = 10,12,14,18) self‐assembled monolayers (SAMs), deposited from ethanol solutions on aluminum oxide, has been monitored in situ using surface plasmon resonance (SPR) spectroscopy. In addition, the two‐solvent approach is used to obtain both film thickness and refractive index fully formed adsorbed layers. A densely packed layer only for longest molecules with 18. chain length solution concentration...

Pleiotrophin (PTN) is a heparin-binding growth factor that plays significant role in tumor and angiogenesis. We have previously shown order for PTN to induce migration of endothelial cells, binding both α(ν) β(3) integrin its receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ) required. In the present study we show synthetic peptide corresponding last 25 amino acids C-terminal region (PTN(112-136) ) inhibited angiogenesis vivo chicken embryo chorioallantoic membrane (CAM) assay...

In this work, the synthesis of long, single-crystal nickel nanowires (NWs) using dc electrodeposition is reported. Porous alumina membranes with 220 nm mean pore diameter were used as a template. This much larger than what usually reported in single crystal NWs synthesis. The dependence NW structure upon applied voltage well change along NW's length also investigated. Finally, order to get sufficient understanding present results, model based on two competing growth mechanisms proposed,...

The formation process of polymer brushes, formed by the adsorption flexible end-functionalized chains from dilute solutions on inner surface cylindrical pores is studied bond fluctuation Monte Carlo simulations. Various properties as grafting density, monomer, and free-end distribution are monitored a function pore diameter D chain length N. Two different modes end-segment attachment considered: (a) pure-irreversible "hard" (b) irreversible "soft" where grafted-ends can move freely but...

In this study, the free-end distribution of a polystyrene self-assembled brush in good solvent (toluene-d) is directly probed by use neutron reflectometry. This accomplished selective deuterium enrichment chains so that all but last 16% monomers each chain are contrast-matched to solvent. Thus, only these unlabeled terminal effectively "visible" neutrons. The analysis experimental results supports picture free ends not localized at height, distributed throughout agreement with previous...

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTShear-Induced Desorption in Polymer BrushesD. L. Anastassopoulos, Ν. Spiliopoulos, A. Vradis, C. Toprakcioglu, S. M. Baker, and Α. ΜenelleView Author Information Department of Physics, University Patras, GR 26 500, Greece, Harvey Mudd College, Claremont, California 91711, Laboratoire Leon Brillouin CEA SACLAY, 91191 Gif-sur-Yvette Cedex, France Cite this: Macromolecules 2006, 39, 26, 8901–8904Publication Date...

Many current research efforts focus on alternative electroacoustic transduction devices having no moving parts, in order to achieve sufficient audio performance from compact solid state devices. Thermoacoustic loudspeakers are transducers based the conversion of A/C signals thermal energy, causing a local fluctuation air pressure which generates acoustic waves. A thermoacoustic actuator does not involve any movement components generate an wave and it is mechanism "virtual" piston produced by...

Abstract The potential application of Surface Plasmon Resonance (SPR) spectroscopy in evaluating the thickness and volume fraction adsorbed macromolecular layers is discussed this work. sensitivity SPR to different layer concentration extension normal surface (thickness) theoretically illustrated. A new approach for interpretation data presented, which applicable whenever functional form density profile known. use proposed procedure fitting experimental results from PS‐PEO brush...

Abstract We have studied the adsorption of end‐attaching block copolymer chains inside cylindrical pores nanoporous alumina. Highly asymmetric PS‐PEO copolymers, with a small PEO anchoring and long PS dangling block, were allowed to adsorb onto porous alumina substrates an average pore diameter ∼200 nm from toluene solution. The process was monitored using FTIR spectroscopy, whereas depth profile analysis performed by means XPS Ar + ion sputtering. It is found that kinetics in are ∼4 orders...

Abstract In this work, the adsorption behavior at silver/toluene and alumina/toluene interface of polystyrene–polyethylene oxide (PS‐PEO) diblock copolymers various molecular weights was investigated by implementation surface plasmon resonance (SPR) technique. This accomplished under a careful choice experimental setup use suitable physical model for interpretation data. Comparison between polystyrene homopolymer PS‐PEO copolymer measurements indicate that is anchored on alumina via PEO...

The equilibrium properties of polymer brushes formed by starlike polymers with varying number arms attached to a surface their center were studied experimentally neutron reflectrometry (NR). Polystyrene (PS) stars in good solvent (toluene) centrally adsorbed onto quartz substrate via zwitterionic anchor group. Increasing the resulted significantly lower adsorbance, while replacement experiments 3-armed star brush linear chains revealed interesting and kinetic features related special...

We describe a novel technique for the characterization of mean pore radius self-ordered porous anodic alumina membranes. have studied flow liquids through cylindrical membrane pores under conditions very low Reynolds number (Re ≪ 1). find that data are well-described by Poiseuille's law. Characterization is achieved application Hägen-Poiseuille equation on measurements conducted in simple and compact experimental setup. This setup allows monitoring as result pressure difference between two...

We present a study of the interaction positively charged model protein lysozyme with negatively amphiphilic diblock polyelectrolyte micelles poly(tert-butylstyrene-b-sodium (sulfamate/carboxylate)isoprene) (PtBS-b-SCPI) on silver/water interface. The adsorption kinetics are monitored by surface plasmon resonance, and morphology is probed atomic force microscopy. micellar described stretched-exponential kinetics, layer shows that do not lose their integrity upon adsorption. complexation...

Measurements of the actual power and silane consumption as a function excitation voltage pressure in completely characterized radio‐frequency, glow‐discharge chamber used for deposition a‐Si:H, are reported. The influence these parameters on discharge impedance is presented discussed with consideration basic electron heating dissipation mechanisms. more efficient, terms amount energy spent per dissociated molecule, at higher pressures lower voltages. This tends toward dissociation threshold...

We have investigated the flow of liquids through anodic alumina membranes with cylindrical nanopores bearing asymmetric polystyrene (PS)–polyethylene oxide (PEO) block copolymer brushes, where short PEO acts as an anchor on surface. The is well described by Poiseuille's law, which allows determination hydrodynamic brush height within nanopores. brushes in good solvent found to vary systematically PS molecular weight, Mw, consistent a power law form Mw3/5. Dramatic changes rate are observed...

The variation of a-Si:H film quality, deposited by a rf glow discharge pure silane, is examined as function the interelectrode distance for two different pressures. Constant photocurrent and modulated methods are used to estimate magnitude shape defect states in valence band conduction band, respectively. An effort made correlate quality parameters formation with plasma macroscopic microscopic parameters. results suggest that, at low distances, high sticking coefficient radicals modify...

The behavior of end-adsorbed bimodal PS–PEO block copolymer systems was studied with neutron reflectivity experiments, both under static conditions (zero shear rate) and a stepwise-increasing flow, up to critical rate where desorption occurs. It is found that when the height one kind chain in brush significantly greater than other, longer chains desorb first, while if heights two constituent kinds are similar, then system responds as whole simultaneously. In particular, ratio components less...

The effect of small disilane addition on the gas phase properties silane-hydrogen plasmas and microcrystalline silicon thin films growth is presented. investigation was conducted in high pressure regime for constant power dissipation discharge with support plasma diagnostics, film studies calculations microscopic parameters dissociation rates. experimental data show a strong electrical window from 2 to 3 Torr that followed by significant raise electron number density drop sheaths electric...

Polysaccharide-protein multilayers (PPMLs) consisting of bovine serum albumin (BSA) and chondroitin sulfate (CS) are assembled in acidic solution (pH 4.2) via layer-by-layer deposition method. The formation PPMLs on gold surface their responsiveness to pH change from 4.2 7 is investigated by Surface Plasmon Resonance Spectroscopy. buildup the multilayer at exhibits non-linear growth while first layers strongly affected physicochemical properties surface. Neutral 7) affects interactions...