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A model for the physical description of water transport through steady-state permeation and dynamic sorption within perfluoro-sulfonic acid (PFSA) membranes has been developed. A broad experimental campaign is conducted on several membranes, belonging to Aquivion class, varying both in thickness and equivalent weight (EW). The experimental data have been used to calibrate and validate water transport model and to find correlations for mass-transfer properties in low-EW PFSA membranes that describe consistently both water vapor permeation and sorption. It has been possible to identify individual contributions to mass transport resistance and to determine the optimal configuration and materials of a full-scale counter-flow membrane humidifier under a set of specific operating conditions.

6 figures, 3 tables., Perfluorinated sulfonic acid (PFSA) polymers such as Nafion® are widely used for both electrolyte membranes and ionomers in the catalytic layer of membrane-electrode assemblies (MEAs) because of their high protonic conductivity, σH, as well as chemical and thermal stability. The use of PFSA polymers with shorter side chains and lower equivalent weight (EW) than Nafion®, such as Aquivion® PFSA ionomers, is a valid approach to improve fuel cell performance and stability under drastic operative conditions such as those related to automotive applications. In this context, it is necessary to optimize the composition of the catalytic ink, according to the different ionomer characteristics. In this work, the influence of the ionomer amount in the catalytic layer was studied, considering the dispersing agent used to prepare the electrode (water or ethanol). Electrochemical studies were carried out in a single cell in the presence of H2-air, at intermediate temperatures (80–95 °C), low pressure, and reduced humidity ((50% RH). %). The best fuel cell performance was found for 26 wt.% Aquivion® at the electrodes using ethanol for the ink preparation, associated to a maximum catalyst utilization., This research was funded by the European Union’s Seventh Framework Programme (FP7/2007–2013) for Fuel Cell and Hydrogen Joint Technology Initiative under Grant no 303452 (IMPACT).

The membrane-electrodes assembly (MEA) is the core of the Polymer Electrolyte Fuel Cell (PEFC). It consists of a membrane, catalytic (CL) and gas diffusion layers (GDL). In order to manufacture MEAs with suitable performance, a hot-pressing procedure is generally used. The relevant parameters are the temperature, pressure and time of hot-pressing. Such variables need to be adjusted as a function of the type of ionomer used in the catalytic layer and membrane. In this study, an evaluation of the temperature of hot-pressing was carried out and its influence on MEA electrochemical performance was assessed. In particular, preparation trials of MEAs were carried out with reinforced experimental membranes based on Aquivion® short-side-chain PFSA (by Solvay Specialty Polymers). The membranes were coupled to gas diffusion electrodes, and MEAs were manufactured using different temperatures for the hot-pressing procedure in order to evaluate their influence on the electrochemical performance of PEFCs, in the temperature range of 80–95 °C, with low relative humidity of the reactant gases. The electrochemical performance of the prepared MEAs was tested in a H2/Air 25 cm2 single cell in terms of polarization curves and accelerated stress test (AST).

The controlled dispersion of polymeric sulfonic acids on suitable heterogeneous supports paves the way to a new catalytic method for the oxidation of a variety of benzylic methylenes to the corresponding carbonyls by using hydrogen peroxide; narrowly dispersed silica nanoparticles covered by fluorinated sulfonic acids ionomers allow selective oxidation of toluene to benzaldehyde, minimizing undesired side reactions and formation of wastes.

Anion-exchange membranes (AEMs) are of growing interest for electrochemical devices such as fuel cells and electrolyzers because the alkaline medium allows avoiding the use of platinum and platinum-group metals as the electrocatalysts. Perfluorinated polymers are a good starting point to prepare AEMs because of their chemical stability and potential high conductivity resulting from the coexistence of hydrophobic main chains and flexible hydrophilic side chains. Here, we report a facile and simple chemical modification of Aquivion® performed in aqueous environment. We obtained a chemically stable membrane with ionic conductivity exceeding 2.5×10−2 S cm−1 at 80 °C and 100 RH% that was used in a polymer fuel cell.

The solvent-free hydrogenation reaction of acetone over bifunctional heterogeneous catalysts, comprising cross-linked perfluorosulfonic acid (PFSA) resins and supported Pd nanoparticles, was investigated in the liquid phase under batch conditions. A systematic study was performed by analyzing separately the effect of the main reaction parameters on the reaction outputs. Acetone conversion, selectivity and productivity to methyl isobutyl ketone (MIBK) were measured as a function of the reaction temperature, the amount of catalyst, the Pd loading, the H2 pressure, the reaction time and the cross-linkage of the polymeric support. Reproducible trends were observed that could be explained in terms of properties of the catalyst, conversion path and kinetics. Best compromise results between selectivity (92 %) and productivity (37.0 mmolMIBK gcat−1 h-1) at 19.7 % acetone conversion were obtained for the 0.26Pd@X-link-08-PW79 catalyst, based on 0.8 % cross-linked PFSA support and 0.26 % wt Pd content.

Over the last three years, a growing amount of reports highlighted the exceptional catalytic performances of Aquivion PFSA in many challenging chemical reactions. To date, all these studies employed Aquivion PFSA in powder form and the impact of shaping Aquivion PFSA on its catalytic performances has never been reported, although this aspect is of prime importance for implementation on a larger scale. Often considered as a matter of practical interest in the current literature, the shaping of a catalyst is actually mandatory and is clearly a key research topic for catalyst design and chemical engineering. Here, we explored the effect of shaping Aquivion PFSA on (1) its catalytic performances (i.e. yield, reaction rate and space time yield), (2) its ease of recovery at the end of the reaction (i.e. filtration, recyclability) and (3) its deactivation rate. In particular, we found that shaping Aquivion PFSA into micropellets was a good compromise (between powder and macropellets) to maintain acceptable catalytic performances while considerably facilitating the recovery of Aquivion PFSA at the end of the reaction. Last but not least, by properly controlling the reaction conditions, it was possible to limit the deactivation of Aquivion PFSA shaped into micropellets, a recurrent problem in catalytic carbohydrate processing.

This study reports the sustainable production of butyl levulinate (BL) from furfuryl alcohol (FA), a highly abundant biomass derived platform obtained from C5 sugars in hemicellulose. FA upgrading is performed adopting a robust and easily recyclable commercial perfluorosulfonic acid resin, Aquivion® P87S, used as cylinder shaped pellets. This approach avoids the use of corrosive and harmful mineral acids allowing a simple separation of the catalyst from the reaction mixture, reducing the cost of equipment materials and disposal or neutralization issues, also resulting in reduced solvent dehydration. Moreover, FA alcoholysis to BL involves butanol as a sustainable reaction medium, also readily obtained from biomass. The catalyst remains stable up to 6 recycles. Furthermore, the absence of heavy by-products and the stability of the catalyst allowed us to perform successive additions of the substrate to the reaction medium to increase the BL concentrations up to 0.66 M (13 wt%).

5-Hydroxymethylfurfural (HMF) production from catalytic dehydration of fructose was studied over mesoporous silica heterogenized perfluorosulfonic acid resin (Aquivion@silica) catalyst. Amphiphilic Aquivion PFSA was used as both acidic and template agent for the sol–gel synthesis of amorphous mesoporous silica which was found very appropriate to effectively immobilize Aquivion resin by using an impregnation method. Various characterizations including elemental analysis, acid-base titration, XRD, FTIR, Raman, N2 adsorption–desorption, SEM and TEM revealed that Aquivion@silica catalyst presented large surface area, sufficient porosity and afforded highly accessible sulfonic acid groups. Efficient and productive HMF production from the dehydration of fructose was achieved in the polar dimethyl sulfoxide (DMSO) solvent at low temperature of 90 °C, i.e. 85% yield of HMF and 43 molHMF molH+ productivity of HMF. The influence of reaction time, reaction temperature, Aquivion loading, catalyst dosage and solvent on the dehydration process was systematically investigated. The catalyst could be regenerated through a simple ion-exchange method and a stable HMF yield was maintained after being used four times.

We describe the rational design of a new versatile family of bifunctional catalytic materials based on the combination of supported metal nanoparticles (Pd, Rh, Ru) and the superacid, perfluorinated Aquivion (R) PFSA polymer. The heterogeneous catalysts were tested in the multi-step valorisation of representative plant derivatives to high-added-value chemicals. Particularly, the conversion of (+)-citronellal to (-)-menthol and levulinic acid to -valerolactone was achieved in one pot and in one stage in the water phase and shows full selectivity at a high conversion level under mild reaction conditions. The results are discussed in terms of the catalyst micro-structure.

A new generation of high performing polymer electrolyte membranes with ultralow platinum group metal loading (in total 0.44 mgPGM cm− 2) has been developed and characterized. High performance was achieved for MEAs based on the short-side chain Aquivion membrane (E98-09S), stabilized Solvay ionomer (D98-06ASX), and optimized catalysts developed by CNR-ITAE (cathode 40% Pt on C and anode: Ir0.7Ru0.3OX). The high performance was verified on several scales ranging from small single cells (3–8 cm2) at CNR-ITAE and IRD to short three-cell stacks at ITM, the latter MEAs having an active area of 130 cm2. A 4000-h single cell steady-state test at 3 A cm− 2 shows that the degradation rate of the ultralow PGM MEAs is 8 μV/h. Minimal reversible degradation was recorded at 80°C although this is pronounced at low temperature (55°C). Current and thermal cycling proved to have limited impact on degradation.

In this work, Aquivion PFSA resin was shown to be an interesting alternative as a heterogenous catalyst for the continuous gas phase reaction of ethanol dehydration in mild conditions, thanks to its high thermal stability and superacid character. This material was confirmed to have a high thermal stability up to 300 °C, after which the desulphonation process began. Under optimised reaction conditions, the Aquivion catalyst showed a conversion of over 90 % ethanol as well as a selectivity to ethylene. The only detected by-product was diethyl ether, the formation of which was facilitated by low temperature. The dehydration activity was shown to depend on the number of acid sites and material shaping. Fluorescence microscopy, used to study the penetration of different alcohols into the shaped Aquivion, indicated the high polarity of ethanol, enabling the permeation into the pellet structure, thus facilitating the use of the -SO3H that is available on the resin, despite its very low surface area. The catalyst’s durability was proven by a stable operation for 14 h on-stream at 150 °C, without a significant evidence of coke deposition.

This manuscript explores the catalytic activity, selectivity and stability of Aquivion ® PFSA PW98 in the oligomerization of glycerol. Aquivion ® PFSA PW98 is a solid superacid catalyst with a Hammett acidity function of −12. Furthermore, the perfluorinated structure allows this polymer to stand quite high operating temperature (up to 150–160 °C) without loss in mechanical and chemical integrity which is of huge interest for glycerol conversion. In this context, we discovered that Aquivion ® PFSA PW98 was nearly fully selective to oligoglycerols up to 80% conversion of glycerol. The oligomerization degree of oligoglycerol and the regioselectivity of the reaction (linear vs branched and cyclic isomers) were fully analyzed by means of GC and SEC chromatographies. In contrast to conventional solid acid catalysts, Aquivion ® PFSA PW98 was found highly robust in glycerol and was sucessfully recycled at least 10 times without apparent decrease in activity or selectivity. A comparison with Nafion NR 50 is also included to shed light on the potential of Aquivion ® PFSA PW98 for acid-catalyzed conversion of glycerol.

6 Figuras, 4 Tablas, The large-scale application of polymer electrolyte membrane fuel cells (PEMFCs) requires a reduction of the costs and an improvement in performance and stability. Particularly, the automotive market needs the PEMFC works under harsh conditions (high temperature, low relative humidity, etc.), maintaining a good performance level and low degradation. These operating conditions permit to mitigate the constraints concerning the thermal and water management allowing both a simplification and a volume reduction of the system inside the car with a strong impact on costs and reliability. However, PEMFCs require the development of the components such as catalysts, ionomers and membranes with a proper stability. In this work, PtCo/KB and Pt/KB electrocatalysts were investigated with the aim of verifying the performance and stability, coupling them with an innovative reinforced Aquivion® membrane. An optimization of the catalytic ink composition was carried out, according to the different ionomers characteristics to be used in the catalytic layer in order to reduce the degradation level. The stability is assessed by considering the variations of the performance and electrochemical parameters, such as electrochemical surface area (ECSA) and mass activity (jm), at the beginning and end of accelerated stress test procedures., The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) for Fuel Cell and Hydrogen Joint Technology Initiative under Grant no 303452 (IMPACT).

The catalytic conversion of biomass and its derivatives into valuable chemicals requires efficient, energy saving, and sustainable technologies. In this work, a variety of bifunctional catalysts are prepared combining immobilized metal nanoparticles and acid solid materials featuring Lewis or Brønsted acidity. The catalytic systems are tested in the reductive amination of bio-derived levulinates with primary amines, using hydrogen as clean reducing agent, to obtain N-substituted-5-methyl-2-pyrrolidones, which are proposed as substitutes for the widely used, REACH-restricted solvent N-methyl-2-pyrrolidone. The overall process is studied in depth to identify the best combination of metal and acid functionalities to be used in one-pot and one stage. Pt immobilized onto the Brønsted solid acid Aquivion is shown to be the most efficient catalyst, with a productivity of N-heptyl-5-methyl-2-pyrrolidone of 7.9 mmolgcat-1 h-1 reached at full conversion and 98.6% selectivity, under 120 °C, 4 bar H2 pressure and solvent-free conditions.

International audience; Proton Exchange Membrane Fuel Cells (PEM-FC) are considered an alternative to the internal combustion engine for transportation. Despite the existence of relevant demonstrations and few commercial fleets, there are still a series of issues such as the durability of the materials and the cost of platinum which limit a wider application in this field. To this regard, better utilization and consequently loading reduction of Pt in electrodes is of outstanding importance. Herein we report the synthesis, characterization and application of an ionomer in the cathode catalyst layer; thanks to its higher oxygen permeability the quantity of Pt may be minimized. This ionomer is a modification of commercial Aquivion ® PFSA obtained by incorporation of a third monomer (2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole, MDO). Results on cast membrane demonstrate a 20% higher oxygen permeability of the new ionomer compared to Aquivion PFSA E87-05S and Nafion NR212 at 100% RH. Furthermore, an improvement of the performance of a PEM-FC in automotive conditions (RH=40-70%) is obtained with the assembly where this ionomer is used as cathode binder. In particular polarization curve at 70% RH shows improvement of 20% of power density peak and electrochemical impedance confirms higher oxygen permeability due to lower mass transport resistance than Aquivion.

The major difference for the durability of the materials in PEM fuel cells and PEM electrolyzers is the exposure to humidified gases and to liquid water, respectively. Aquivion and Nafion ionomer was investigated at surfaces of membranes and cross-sections of electrodes by material-sensitive atomic force microscopy. The dimensional behavior of electrodes and membranes in a membrane-electrode assembly cross section was studied as a function of combined humidity and temperature changes. The observed opposite effects of ionomer dimensional changes in membrane and catalytic layers are important for understanding mechanical stress factors and degradation. For the lamellar polymer phase at moderate humidity, a linear swelling behavior and the enclosure of multiples of 0.8 nm-thick water layers was observed. Submersed in water, 3 nm-thick enclosed water layers were found. At the water-immersed Aquivion membrane derived from alcoholic dispersion larger 30–50 nm sized water-rich areas were found. In contrast, for membranes derived from water-based dispersion the water-rich phase was smaller with 11 nm. The thickness of the ultrathin ionomer layers in the electrode was investigated as a function of humidity and temperature. A linear swelling was found for humidity changes whereas nonlinear behavior with 100% expansion and hysteresis was seen for temperature cycles.

The function of catalytic layers in fuel cells and electrolyzers depends on the properties of the ionically conductive phase, which are most commonly perfluorinated ionomers based on Nafion and Aquivion. An analysis by atomic force microscopy reveals that the ultrathin ionomer films around Pt/C agglomerates have a thickness distribution ranging from 3.5 nm to 20 nm. Their conductivity and gas permeation properties determine the fuel cell performance to a large extend. For electrodes in Aquivion-based membrane-electrode-assemblies operation-induced structure changes were investigated by means of material- and conductivity-sensitive atomic force microscopy, infrared spectroscopy and electron-dispersive X-ray analysis. The observed thinning of the ultrathin ionomer films was mainly caused by polymer degradation deduced from reduced swelling after long-time operation and a significant loss of ionomer with operation time detected by infrared spectroscopy. From the linear thickness increase of the ultrathin films with rising humidity, a mainly layered structure of the ionomer was deduced. An influence of thickness of such ultrathin ionomer films on fuel cell lifetime was found by analysis of differently prepared membrane-electrode-assemblies, where a linear increase of irreversible degradation rate with ionomer film thickness in the electrodes of unused membrane-electrode-assemblies was found.

Endothelial cells are constantly exposed to blood flow and the resulting frictional force, the wall shear stress, varies in magnitude and direction with time, depending on vasculature geometry. Previous studies have shown that the structure and function of endothelial cells, and ultimately of the vessel wall, are deeply affected by the nature of wall shear stress waveforms. To investigate the in vitro effects of these stimuli, we developed a compact, programmable, real-time operated system based on cone-and-plate geometry, that can be used within a standard cell incubator. To verify the capability to replicate realistic shear stress waveforms, we calculated both analytically and numerically to what extent the system is able to correctly deliver the stimuli defined by the user at plate level. Our results indicate that for radii greater than 25 mm, the shear stress is almost uniform and directly proportional to cone rotation velocity. We further established that using a threshold of 10 Hz of wall shear stress waveform frequency components, oscillating flow conditions can be reproduced on cell monolayer surface. Finally, we verified the capability of the system to perform long-term flow exposure experiments ensuring sterility and cell culture viability on human umbilical vein endothelial cells exposed to unidirectional and oscillating shear stress. In conclusion, the system we developed is a highly dynamic, easy to handle, and able to generate pulsatile and unsteady oscillating wall shear stress waveforms. This system can be used to investigate the effects of realistic stimulations on endothelial cells, similar to those exerted in vivo by blood flow.

A simple and broadly applicable preparation procedure to obtain silica-supported transition metal (namely Cr, Co and Mn)-based radical scavengers, containing sulfonic acid functionalities, is reported. These systems are widely characterised in terms of structure, bulk and surface composition and morphology by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), X-Ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The scavenger material is loaded in ePTFE reinforced membranes prepared from Aquivion ® perfluorosulfonic acid (PFSA) dispersions. All these composite membranes show longer lifetime in Accelerated Stress Tests (AST) and reduced fluoride release in Fenton's tests than the scavenger-free membranes without any loss in electrochemical performance. The Cr-scavenger-based polymer electrolyte shows a three-time larger stability than the pristine membrane.

A new protocol for the diasteroselective synthesis of pyrrolidin-2-ones 4–14 is presented. Aquivion PFSA effectively catalyzed the diasteroselective nitro-mannich/lactamization cascade reaction between the imine formed from aldehydes 1a–g and amines 2a–b with methyl 3-nitropropanoate 3. The use of flow conditions allow a very efficient waste minimization confirmed by representative green metrics calculations.

Here, we investigated that the mechanocatalytic depolymerization of cellulose in the presence of Aquivion, a sulfonated perfluorinated ionomer. Under optimized conditions, yields of water soluble sugars of 90-97% were obtained using Aquivion PW98 and PW66, respectively, as a solid acid catalyst. The detailed characterization of the water soluble fraction revealed (i) the selective formation of oligosaccharides with a DP up to 11 and (ii) that depolymerization and reversion reactions concomitantly occurred during the mechanocatalytic process, although the first largely predominated. More importantly, we discussed on the critical role of water contained in Aquivion and cellulose on the efficiency of the mechanocatalytic process.

The perfluorosulfonic acid (PFSA) Aquivion PW98 is an amphiphilic solid superacid which is shown to catalyze the conversion of cellulose into amphiphilic alkyl glycosides (AAGs) in 85 % yield (with 97 % selectivity). The process involves a mechanocatalytic depolymerization of cellulose followed by a direct glycosylation with n-dodecanol. In comparison to H2 SO4 and solid acid catalysts commonly employed in cellulose processing, Aquivion PFSA PW98 is not only recyclable but also exhibits superior catalytic performances in terms of yield, selectivity, and reactor productivity.

The catalytic performance of Aquivion PFSA, a solid superacid, was investigated in the catalytic glycosylation of glucose with fatty alcohols. Four main criteria were considered to evaluate the catalytic performance of Aquivion PFSA: (1) the selectivity of the reaction, (2) the turnover frequency, (3) the reactor productivity, and (4) the catalyst stability/recycling. To shed light on the catalytic performance of Aquivion PFSA, it was systematically compared to H2SO4, which is industrially employed in such reactions. We discovered that Aquivion PFSA surpassed the catalytic performance of H2SO4 in terms of activity, selectivity, and reactor productivity. In particular, Aquivion PFSA selectively converted glucose to alkyl polyglucosides (DP = 1.2) with 85% yield, which corresponded to a reactor productivity as high as 477 kg/(m3 h). Conversely to H2SO4, Aquivion PFSA was also capable of selectively producing alkyl polyglucosides directly from glucose syrup, a cheap source of glucose. This result was ascribe...

A facile synthesis, based on a wet impregnation technique and a thermal treatment, of a novel silica-supported cerium-oxide-based radical scavenger bearing sulfonic acid functionalities is presented. This material is loaded as a filler in ePTFE reinforced membranes (called R79-02S) prepared starting from Aquivion ® Perfluoro-Sulfonic Acid (PFSA) dispersions. The aim is to mitigate the peroxy radicals attack to the polymeric membrane under fuel cell operating conditions. These membranes show much longer (7 times more) life-time in Accelerated Stress Tests (AST) and reduced fluoride release (about one half) in Fenton's tests than the radical scavenger-free membrane without any loss in electrochemical performance. Scavenger-free Aquivion ® PFSA-based membrane durability is about 200 h in AST whereas the same membrane containing the newly developed radical scavenger exceeds 1400 h. These results confirm the stability of the modified membranes and the excellent activity of the composite scavenger in mitigating the polymer electrolyte degradation.

Recent interest in alternative energy technologies promoted the development of perfluorinated polymer membranes for fuel cells; the degradation mechanism occurring during operation and the polymer ageing that may lead to membrane failure are still a matter of investigation with the aim to identify proper testing protocols and analytical methods. This study illustrates some results obtained through micro Raman spectroscopy; this analytical technique showed itself to be a powerful tool in terms of spatial resolution and chemical data gathering. Detailed analytical and structural information along the cross sections of two membrane grades have been presented, shedding light on intrinsic structural modifications related to overall membrane performance. This study clearly shows an ununiformly distributed loss of sulfonic groups in two different Aquivion ® membrane grades, being the spectroscopic technique able to unveil very subtle effects due to equivalent weight and membrane thickness variations. The overall results support the mechanism previously proposed by other authors using different analytical techniques.

In this paper, we present a straightforward synthesis of bimetallic radical scavengers supported onto silica and an evaluation of their effectiveness to increasing the lifetime of Aquivion® PFSA membranes. Such scavengers comprise cerium (Ce) and chromium (Cr) and were incorporated in e-PTFE reinforced thin membranes through suspension in water-based Aquivion® PFSA dispersion. The bimetallic samples were physico-chemically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Energy Dispersive X-ray (EDX) analyses and compared to the monometallic Ce and Cr scavengers prepared in the same way. The membranes containing the mono- or bi-metallic scavengers were electrochemically investigated in terms of polarization behavior, cell resistance and durability. The MEA based on monometallic Ce-based scavenger showed the largest durability (7-time more than a reference MEA). The bimetallic scavenger appears also very promising. However, a proper optimization of the composition is required for its application in highly durable composite Aquivion® membrane.

A robust method for coating polydimethylsiloxane (PDMS) allowing covalent binding of biomolecules is reported. The coating is based on adsorption of a copolymer, copoly(DMA-NAS-MAPS), bearing functional groups. The polymer is synthesized by free radical polymerization; it self-adsorbs onto the PDMS very rapidly, typically in 30 min, even without any PDMS surface pre-treatment. PDMS slides coated by copoly(DMA-NAS-MAPS) covalently bind amino-modified DNA fragments and have been tested in bacterial genotyping experiments. The usefulness of this functional coating on PDMS structures in lab-on-chip devices powered by microfluidics has been demonstrated. The copoly(DMA-NAS-MAPS) coated PDMS slides were used as flexible components of a microcell in semi-automated DNA microarray experiments for rapid food pathogen identification.

In the few last years, the need of reliable, fast and inexpensive methods for selective analysis of specific substances in complex mixtures has grown exponentially. In particular, the detection of biomolecules, such as oligonucleotides, proteins, peptides and carbohydrates is of outstanding importance in gene expression, drug design and medicine studies. To these purposes, molecular recognition on microarray-configured devices is one of the most promising tools. This technology uses a number of different substrates such as glass, silicon, alumina or gold-coated slides. The use of polymers is a very effective way to tailor surface properties introducing functional groups able to bind biomolecules and prevent denaturation and non-specific binding. Furthermore, advanced polymers, thanks to their particular physico-chemical properties, can be used to improve selectivity and sensitivity during assays. This review will provide very recent examples of polymer-mediated molecular recognition between guest molecules in solution and host molecules located at the solid phase.

A quantitative in situ investigation of the structure of the catalytic layer of polymer electrolyte membrane fuel cells using material-sensitive and conductive atomic force microscopy is reported. The distribution and size of the ionomer phase at the surface of the catalytic layer is retrieved from adhesion force mappings, measured at high humidity and up to 75 °C. The average ionomer layer thickness varies between 7 and 13 nm for three differently prepared samples, as concluded from the histograms. Evidence of a lamellar structure of the thinner ionomer layers is presented. A significant thinning of the ionomer layers after long-term fuel cell operation is observed.

Carboxy-terminated polyvinylpyrrolidin-2-one (PVP) has been used as a new water-soluble and biocompatible polymeric support for a series of ferrocene labeled amino acid and peptide nucleic acid (PNA) monomer derivatives 4 – 7 . The organometallic polymer-conjugates thus obtained are new and potentially useful as water-soluble electrochemically active probes for biomolecules. In view of such application, their electrochemical activity has been evaluated and has proved very high notwithstanding the complexity and bulkiness of the molecule, affording detection limits down to 10 −8 M in the aqueous medium.

Novel l-vinylpyrrolidin-2-one (VP) derivatives, namely 3,3-di(ethoxycarbonyl)-1-vinylpyr rolidin-2-one (DEVP) and 3-(ethoxycarbonyl)-l-vinylpyrrolidin-2-one (EVP), were obtained through a two-step synthetic pathway involving the abstraction of a hydrogen atom a to the lactam C=0, followed by condensation with ethyl chloroformate. By properly selecting the reaction conditions, DEVP could be obtained in high yields, through a straightforward purification procedure. Both DEVP and EVP were converted to sodium 1-vinylpyrrolidin-2-one-3-carboxylate (VP-COONa) by saponification of the ester group, followed by decarboxylation reaction in the case of DEVP. All monomers were homo- and copolymerized with VP by radical polymerization, the structure of the polymer obtained was determined by means of 1 H and 13 C NMR spectroscopy, and molecular weights were analyzed by means of size exclusion chromatography. The resultant DEVP- and EVP-based polymers also underwent hydrolysis with alkali solutions, followed by decarboxylation reaction in the case of DEVP units, which led in all cases to one carboxylate function linked to the lactam ring. The reactivity ratios for the copolymerization of DEVP with VP were determined in methanol solution according to the Kelen-Tudos procedure, through polymerization experiments performed at different feed, in which compositional drifts were followed by monitoring monomer conversions by means of 1 H NMR spectroscopy. The values of the reactivity ratios obtained were r DEVP = 0.63 and rvp = 0.33. The validity of these parameters was checked by means of the classical Skeist equation.

Thanks to their robustness, reliability and ease of use, step motor drives are widely used in several fields, mainly for small size automation. Step motor drives have also some well known bad running conditions related to their oscillatory behaviour and synchronism loss. In order to properly design the application, those conditions must be accurately taken into account setting-up proper mathematical models. In particular in this paper we refer to a simplified electro-mechanical model where the most of the parameters can be drawn from datasheets, while the others, as the equivalent damping factor, need experimental investigation. This paper deals with preliminary experimental activities performed on small size step motor drives for both testing the suitability of a test bench designed and developed in previous works, and outlining some remarks on the behaviour of the tested motors.

Multilayer actuators (MLA) are among the piezoelectric devices best suited to be introduced into fast and high-precision mechanical systems, because of their relatively large strokes and short actuation time. Several analytical models of their dynamic behaviour were developed during the last decades but none considered the real structure of the multilayer actuator. In this paper a more detailed model of a generic mechanical system driven by a piezoelectric multilayer actuator is presented. A complete description of such model is given and a comparison to existing modelling techniques is made. The behaviour of some commercially available actuators is analysed and results are discussed.

A new Aquivion™ E79-03S short-side chain perfluorosulfonic membrane with a thickness of 30 μm (dry form) and an equivalent weight (EW) of 790 g/equiv recently developed by Solvay-Solexis for high-temperature operation was tested in a pressurised (3 bar abs.) polymer electrolyte membrane (PEM) single cell at a temperature of 130 °C. For comparison, a standard Nafion™ membrane (EW 1100 g/equiv) of similar thickness (50 μm) was investigated under similar operating conditions. Both membranes were tested for high temperature operation in conjunction with an in-house prepared carbon supported Pt electrocatalyst. The electrocatalyst consisted of nanosized Pt particles (particle size ∼2 nm) dispersed on a high surface area carbon black. The electrochemical tests showed better performance for the Aquivion™ membrane as compared to Nafion™ with promising properties for high temperature PEM fuel cell applications. Beside the higher open circuit voltage and lower ohmic constraints, a higher electrocatalytic activity was observed at high temperature for the electrocatalyst-Aquivion™ ionomer interface indicating a better catalyst utilization.

The Hardware in the Loop simulation is an useful instrument to simulate complex mechanical systems in which the subject of the test is an hardware component. The results of the simulation, closer to the real behavior of the system, are the main advantage of this approach. This application is often used during the design process to test components of a complex mechanical system before the development of the prototype (e.g. embedded systems). The literature examples show, in general, mathematical model finalized to the application. The objective of this work is focused on the development of a generic Multi-Body software for HIL applications. Some simulations examples, the dynamic of a slider-crank and of a McPherson suspension, are presented at the end of the paper.Copyright © 2010 by ASME

Electro-hydraulic elevators are widely used systems, especially in low level buildings, due to their very good ratio between power generation and dynamic response. Generally, the goal of an elevator system is just to reach the floor with a precision enough to be comfortable for the passengers, without the need to follow a specific law of motion; hence an open-loop control system could be enough. Otherwise such a kind of solution reduces the number of components, bringing down the costs of production. On the other hand a complete knowledge of the mechanical system’s behaviour is required. In this work we deal with the analysis of the behaviour of a commercial hydraulic elevator driven by an open loop control that monitors the downstream pressure of the proportional valve supplying the cylinder. At the end of the paper, a closed loop solution based on the pressure measurement and on the motion time is proposed.Copyright © 2009 by ASME

In the hit to lead process, a drug candidate is selected from a set of potential leads by screening its binding with potential targets. This review focuses on the lead identification assays that employ a bio-chemical or bio-physical test to detect molecular recognition events between proteins and small molecules in a parallel format. These tests require either the lead or the target immobilization followed by incubation with the set of potential interaction partners and detection of a signal related to the target-ligand binding. In the first part of the review the different detection strategies amenable for drug screening are discussed. In the second part, a review of immobilization approaches for leads or targets, allowing the parallel screening of arrays of molecules, is presented.

The reactivity of carboxy-terminated poly(1-vinylpyrrolidin-2-one) (PVP-COOH) 40-mers 1 with various small bi-functionalized molecules has been investigated. A number of new differently functionalized PVP 3–11 have been successfully obtained demonstrating that the presence of the bulky PVP chain did not hamper the reactivity of the carboxy group. This would imply that in solution the carboxyl group is not buried inside the coil, but well exposed to the solvent, as further confirmed by a molecular dynamics conformational study. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1683–1698, 2008