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International audience; The durability of paper documents treated with aminoalkylalkoxysilane copolymer (co-AAAS) flexible networks, as deacidifying and strengthenening agents, was studied. To this end, a 1922 lignocellulos ic newsprint paper was treated with co-AAASs and characterized. Physico-chemical properties such as pH, chromatism, opacity and mechanical strength were measured shortly upon treatment and several years after. In order to better understand the role of the initial degradation state of the paper and the impact of its constituents other than cellulose (lignin, alum-rosin sizing) on the treatment efficiency, several laboratory papers were added as models. It was shown that alum-rosin sizing contributed to a decrease in pH of the most degraded treated paper over the monitoring time, whereas the strengthening effect was mostly affected by the presence of lignin. In particular, for most papers, after several years, the gain in folding endurance was the lowest in the lignin-rich ones. The breaking length of all the papers increased post-treatment and over time, independently of the paper constituents. This was attributed to the slowly progressing aminoalkylalkoxysilanes polycondensation, on the scale of years, as evidenced by Cross Polarisation-Mass Angle Spinning 29 Si solid-state Nuclear Magnetic Resonance.

In this work, we describe an eco-friendly and cost-efficient method for the production of highly dispersed few-layer graphene solution using karaya gum as bio-inspired exfoliating agent. The as-synthesized graphene aqueous solution can be easily applied on paper sheet through dip- or brush-coating thanks to the binding properties of the gum and to the functional groups on the paper surface with the graphene sheets. The as-synthesized composites display high mechanical strength and high electrical conductivity for numerous downstream applications. Electronic circuits can be designed on such graphene-paper composites either by controlling the graphene deposit or by post-laser etching with high lateral resolution. The laser beam can also be used to create local graphitization or partial etching of the conductive line in order to generate conductive areas with different resistance. The designed smart graphene paper was experimentally tested in different electronic applications, such as lightweight conductive circuit, as well as flexible keyboard which can be directly linked to a computer, thus opening up a new route for the development of daily life connected objects.

Generated in the pulp and paper production process, cellulosic pulp fines are fibrous cellulosic materials capable of passing a 200 mesh screen. Processed pulp fines remain in the pulp and affect pulp and paper sheet properties. Their specific morphology promotes interactions with fibers and alters sheet properties. Nevertheless, the 3D distribution of fines in paper sheets has not been revealed so far. Localizing fines within a matrix of fibers is challenging since both elements have the same chemical composition and fines have small dimensions. It is required to increase the contrast of pulp fines, while avoiding any alteration of initial fines morphology. In this study, fines were first separated and labeled with Rhodamine B isothiocyanate, a fluorescent dye. Labeled fines were blended with pulp at different concentrations and paper sheets were produced from each mixture. Prior to imaging, pulps and handsheets were characterized by standard pulp and paper tests and compared with references, showing no significant differences between sheets containing labeled and untreated fines. Thus, mechanical and physical tests indicated that no, or only minor alteration of fines properties by the labeling process occurred. We then applied two imaging techniques to detect the labeled pulp fines in the paper network, namely confocal laser scanning microscopy and multiphoton microscopy, visualizing the 3D distribution of fluorescent fines within the fiber network. The results obtained also allowed a differentiation between morphologically different fines showing fiber fragments more attached to single fibers whereas more fibrillar fines concentrate in fiber–fiber joints, thereby strengthening bonding.

cited By 0; In this work, we design new plasmonic paper-based nanoplatforms with interesting capabilities in terms of sensitivity, efficiency, and reproducibility for promoting multimodal biodetection via Localized Surface Plasmon Resonance (LSPR), Surface Enhanced Raman Spectroscopy (SERS), and Metal Enhanced Fluorescence (MEF). To succeed, we exploit the unique optical properties of gold nanobipyramids (AuBPs) deposited onto the cellulose fibers via plasmonic calligraphy using a commercial pen. The first step of the biosensing protocol was to precisely graft the previously chemically-formed p-aminothiophenol@Biotin system, as active recognition element for target streptavidin detection, onto the plasmonic nanoplatform. The specific capture of the target protein was successfully demonstrated using three complementary sensing techniques. As a result, while the LSPR based sensing capabilities of the nanoplatform were proved by successive 13-18 nm red shifts of the longitudinal LSPR associated with the change of the surface RI after each step. By employing the ultrasensitive SERS technique, we were able to indirectly confirm the molecular identification of the biotin-streptavidin interaction due to the protein fingerprint bands assigned to amide I, amide III, and Trp vibrations. Additionally, the formed biotin-streptavidin complex acted as a spacer to ensure an optimal distance between the AuBP surface and the Alexa 680 fluorophore for achieving a 2-fold fluorescence emission enhancement of streptavidin@Alexa 680 on the biotinylated nanoplatform compared to the same complex on bare paper (near the plasmonic lines), implementing thus a novel MEF sensing nanoplatform. Finally, by integrating multiple LSPR, SERS, and MEF nanosensors with multiplex capability into a single flexible and portable plasmonic nanoplatform, we could overcome important limits in the field of portable point-of-care diagnostics. © 2019 Campu, Susu, Orzan, Maniu, Craciun, Vulpoi, Roiban, Focsan and Astilean.

Cellulose is an attractive reagent for the elaboration of C-containing materials, but here, we also considered it as an O-provider for preparing macro, micro and nano-fibrous Nb2O5/C composites by a new mineralization with Nb2Cl10 in anhydrous conditions. Our study highlights differences of reactivity between filter paper, microfibrillated or bacterial cellulose in connection with the crystallinity and the accessibility of the hydroxyl groups. The Nb2O5/C ratio was found to be adjustable (55?75% of Nb oxide) depending on the cellulosic precursor. Our composites were tested as electrodes that could be used as negative electrode in hybrid lithium-capacitor. Electrochemical characterizations of Nb2O5/C composites are reported and it was demonstrated that characteristics of the starting cellulosic reagents that influence physico-chemical properties of composites thus impact electrodes performances. Very interestingly, for 1C charging/discharging rates, capacities as good as thus of literature (150 mAh g−1) were obtained using our new sustainable synthesis protocol. Fil: Henry, Aurélien. Université Montpellier II; Francia Fil: Le Vot, Steven. Université Montpellier II; Francia Fil: Alauzun, Johan G.. Université Montpellier II; Francia Fil: Hesemann, Peter. Université Montpellier II; Francia Fil: Foresti, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina Fil: Cerruti, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina Fil: Heux, Laurent. Université Montpellier II; Francia Fil: Fontaine, Olivier. Université Montpellier II; Francia Fil: Boury, Bruno. Université Montpellier II; Francia

International audience; A cellulose paper sheet, chemically modified with azide functions, is described to be a versatile molecular platform for copper-catalyzed 1,3-dipolar cycloaddition with terminal alkynes. This 3-step methodology was carefully optimized at each stage of the process with the support of experimental and physical evidences. Our approach allows the surface coverage of structurally diverse molecular architectures through a covalent grafting with non-hydrolysable chemical linkers. This robust linkage is highlighted with the surface hydrophobization of cellulose paper through the click ligation of cholesterol units as renewable and inexpensive hydrophobic agents. The resulting water-resistant and water-repellent paper-based material shows powerful oleophilicity properties and displays a high contact angle of 139.6°.

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International audience; Complex cellulosic samples are often difficult to analyse with size-exclusion chromatography. The strong molecular associations of hemicelluloses and lignin with cellulose produce multimodal molar mass distributions (MMD) that are difficult to interpret. More reliable ways of calculating the molar masses of cellulose are thus necessary. This is particularly relevant when studying the kinetics of paper degradation, as the number average molar mass is the most precise indicator. In this study various data handling methods based on the deconvolution of bimodal and multimodal MMDs of complex cellulosic samples after SEC-MALS-DRI analysis are examined in order to propose more accurate paper degradation rates. Two deconvolution methods, which do or do not rely on polymer calibration curves were developed and were applied to several kraft and groundwood pulp papers unaged and hygrothermally aged. The deconvolution methods are discussed and evaluated in light of calculated cellulose activation energies, degradation rates and paper usable lifetime predictions.

Various parameters that may affect the efficiency of tri- and di-functional aminoalkylalkoxysilanes (AAAS) copolymer treatments to deacidify and mechanically strengthen aged complex papers (lignocellulosic pulp, additives) were studied. Three model papers were first hydrothermally aged (90 °C—50% RH) in order to achieve physicochemical characteristics similar to those of a naturally aged newsprint, and were then treated with AAAS copolymers. The chemical composition of the treatments varied from 50 to 5 wt% of tri-functional monomer APTES, the latter acting as cross-linker in the copolymer network. The respective ratio of tri- and di-functional monomers in the mixture was shown to greatly influence the mechanical properties of the treated papers in the case of APTES/DIAMINO but less so in the case of APTES/AMDES. If APTES/DIAMINO (50/50 wt%) did not strengthen the degraded papers, a higher proportion of DIAMINO (95 wt%) and lower proportion of APTES (5 wt%) led to improving the tensile strength and, more importantly for the function properties of paper, significantly enhancing the folding endurance. The treatment efficiency decreased at higher state of deterioration of the papers and in the presence of alum–rosin sizing. Lastly, the treatments developed for the artificially aged model papers were applied to the degraded newsprint paper specimen and successfully enhanced its mechanical properties.

Fibrous cellulosic materials have been used as templates for material synthesis or organization via thermal degradation of the cellulose. Most of these methods, however, fail to exploit fiber organization, in part due to loss of structure with processing. Herein, we demonstrate that chemi- and physi-sorbed modifiers of cellulose alters the thermal degradation mechanism allowing for controlled deposition of oxide and carbon (incomplete combustion) along the original paper fiber network. We demonstrate that the degradation of the cellulose fibers depends on the amount of physisorbed material due, in part, to effect on the propagation of the ignition event. From the distribution of the residual elements and shape of the deposits, we can infer that the thermal degradation process depends on the nature, and concentration, of filler(s) or occluded.

International audience; We clarify some analytical expressions existing in the literature, • Within the correct formulae we conclude that there is no need for an ad hoc improvement on the opposite to the title paper, • We highlight the symmetry properties of the function to be integrated in order to agree with the usual assumptions made to derive the Kramers-Kronig relations, • The analytical formula we provide may be used to increase the accuracy of the "Poor Man's Kramers-Kronig analysis" method and the "Kramers-Kronig constrained variational analysis" method.

International audience; The aim of the research was to evaluate the influence of certain components of paper such as lignin and papermaking additives (fillers and sizing) on the efficiency of a recently proposed treatment for simultaneous deacidification and mechanical strengthening with polyaminosiloxane copolymer networks. Mixed mechanical and chemical pulp papers containing various additives were treated with aminoalkylalkoxysilanes (AAAS) by immersion or by spray. Upon treatment, the deposited alkaline reserve varied from 0.34 to 1.14 mol kg −1 . For all the papers, copolymers formed from binary mixtures of a di- and a tri-functional AAAS provided the best improvement in the mechanical properties, i.e. in the tensile strength and the folding endurance, indicating an increase in the interfiber bonding energy and in the paper flexibility and plasticity, respectively. It was found that fillers had no influence while sizing hampered the efficiency of the treatment. The presence of mechanical pulp was shown to have a significant impact on the effect of the treatments as well by increasing the tensile resistance more than the folding endurance, indicating an increase in the paper rigidity. This observation was attributed to the response of lignin to the treatment.

In this paper, we report the first successful implementation of a complete paper-based water management system (WMS) that collects the excess water at the cathode of a microfabricated packageless fuel cell (PLFC) and redistribute it to its anode and to an evaporation surface that simulate a hydride-based hydrogen generator. Five configurations of WMS were tested on a 1 cm2 air-breathing PLFC and show that with the best configuration, the power output of the cell can be improved by 90% for at least 24h. We experimentally demonstrate that not only cathode flooding issues must be address to obtain an efficient WMS but also that anode drying plays a major role in poor performance of small air-breathing fuel cells. Finally, with the optimal configuration of WMS, the PLFC in air-breathing mode shows similar performances as with humidity controlled air forced-flow.

International audience; An analytical method based on the combination of on-line pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry and multivariate analysis for a direct characterization of traditional East Asian handmade papers is presented here. The method was applied to three kinds of widely used handmade papers in East Asia followed by an attempt of identification of ancient lining papers belonging to museum samples of unknown origin. The results indicated that Py-GCxGC/MS, together with multivariate data analysis, was more efficient and reliable compared to the compound presence/absence analysis to meet the challenging search for organic markers in rare cultural heritage materials. The established method showed promises as an efficient analytical tool for the characterization of artwork and culture heritage materials and in filling the lacuna for papermaking fiber analysis which is currently almost entirely relied on microscopy analysis. Results also revealed that two-dimensional techniques could constitute an efficient approach for the analysis of complex artwork samples to circumvent the limitation of materials at disposal in cultural heritage studies.

A chemically modified cellulose filter paper with ethylenediaminetetraacetic acid (EDTA) is described as a device for metal remediation. This new material was prepared by esterification of the paper with EDTA dianhydride. The high hydrophilicity of cellulose paper associated with the strong chelating properties of the EDTA moieties for metals allow the treatment of water samples containing various metal cations, including Ag(I), Pb(II), Cd(II), Ni(II), Zn(II), Sn(II), and Cu(II), with 90–95% removal efficiency. The mechanism of adsorption was deeply studied with the support of kinetic experiments and adsorption isotherms. As a practical feature, one can note that the cellulose–EDTA material works at a wide range of pH values and can be used either as a solid adsorbent or a membrane for continuous wastewater treatment.

International audience; Cellulose paper degradation products forming in the “tideline” area at the wet-dry interface of pure cellulose paper were analyzed using gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) and high-resolution electrospray ionization-mass spectrometry (ESI-MS, LTQ Orbitrap) techniques. Different extraction protocols were employed in order to solubilize the products of oxidative cellulose decomposition, i.e., a direct solvent extraction or a more laborious chromophore release and identification (CRI) technique aiming to reveal products responsible for paper discoloration in the tideline area. Several groups of low molecular weight compounds were identified, suggesting a complex pathway of cellulose decomposition in the tidelines formed at the cellulose-water-oxygen interface. Our findings, namely the appearance of a wide range of linear saturated carboxylic acids (from formic to nonanoic), support the oxidative autocatalytic mechanism of decomposition. In addition, the identification of several furanic compounds (which can be, in part, responsible for paper discoloration) plus anhydro carbohydrate derivatives sheds more light on the pathways of cellulose decomposition. Most notably, the mechanisms of tideline formation in the presence of molecular oxygen appear surprisingly similar to pathways of pyrolytic cellulose degradation. More complex chromophore compounds were not detected in this study, thereby revealing a difference between this short-term tideline experiment and longer-term cellulose aging.

The use of cyclopropenone derivatives as latent photo-released strained cyclic alkynes is reported for the covalent printing of complex patterns on cellulose paper. Two different approaches using either a UV LED or a laser as light irradiation source are discussed. While the high intensity of the laser damages the grafted molecular layer, the use of a simple UV LED allows the printing in only 8 min at room temperature with a good resolution at the micrometer scale with negligible diffusion. The validity of this strategy is demonstrated through the sequential printing of a QR code and a logo on the same paper sheet.

International audience; Inkjet-printed PEDOT:PSS electrodes are shown to record cutaneous electrophysiological signals such as electrocardiograms via a simple finger-to-electrode contact. The recordings are of high quality and show no deterioration over a 3 month period, paving the way for the development of the next generation of low-cost, convenient-to-use healthcare monitoring devices.

International audience; The demand for rapid diagnostic in developing countries has recently increased, in part due to growing populations, emerging diseases, and rise in healthcare cost. Use of low-cost lateral flow/dipstick devices, especially paper-based ones, has increased. In most of the developing world, however, biomedical waste management systems either do not exist or are poor, as such, used devices either get incinerated or dumped alongside household trash. The plastic casing that is often used to hold the test strip, while useful before the test, also slows the biodegradation of the used contaminated devices. We demonstrate that by replacing the plastic casing with paper encasements, we promote biodegradation of these devices while reducing its total weight, making their transport and packaging more compact and more environmentally friendly—hence qualifying this simple modification as green engineering. The ability to use paper casing has the added advantage that devices can be readily assembled locally with ease and without need for sophisticated manufacturing tools as needed with the plastic casings.

International audience; Porous 3-D current collectors have been shown to be the primary choice in replacing classical 2D aluminum foil in applicable developments, especially those using carbon-based current collectors. In this study, we investigated the impact of using a non-woven carbon (NWC) based current collector for sulfur electrodes, in terms of performance and practical use in a commercial battery, keeping in mind the simplicity of electrode preparation method. The benefits of using NWC as a 3D current collector include high sulfur utilization for even highly loaded electrodes, lower polarization, and the provision of an efficient electrolyte reservoir. High discharge capacities up to ∼1200 mAh g−1 can be obtained at moderate C-rates, with relatively good capacity retention (

The influence of pressure on the optical properties of nanostructured tetragonal Cu2Sb has been investigated jointly by experimental Raman spectroscopy (RS) and theoretical first-principles calculation based on density functional theory (DFT) varying pressure from zero (ambient condition) to 45 GPa. The DFT determined pressure dependence of the Raman active modes and the mode-Gruneisen parameters for each Raman mode are found to be in excellent agreement with those experimentally determined. Comparison of the pressure evolution of the experimental Raman data with those of DFT has allowed us to make the proper assignment of optical phonon modes.

This brief Technical Report summarizes the key points on the nomenclature of macromolecules and polymers.

International audience; Iron gall inks have largely been used for writing in European western countries from the Middle Ages to the twentieth century. Yet, their use may significantly damage the paper through acid hydrolysis and iron catalysed oxidation. These phenomena are not only governed by the chemistry of the ink + cellulose system, but also by the penetration of the ink within the paper sheet. Here, we investigate ink penetration at the scale of a paper fibre using synchrotron-based STXM. This technique allows in situ mapping of the iron redox state and carbon speciation down to the sub-micrometre scale. Linen fibres have been impregnated by iron sulphate, gallic acid and gum Arabic; i.e. the three main ingredients of iron gall inks. Soft X-ray transparent ultrathin foils of impregnated fibres have been extracted using FIB milling. The data reported here evidence that ink components do not penetrate through the paper fibres the same way. In the absence of gum Arabic, gallic acid penetrates within the fibre but mostly remains in the outer part of the cell wall. A significant precipitation of Fe(III) gallate occurs during this migration whereas small amounts of iron (mostly Fe(II)) penetrate through the inner part of the fibre. The addition of gum Arabic as a binder makes the ink more viscous and significantly jeopardizes its ability to penetrate the fibre. The ink thus remains at the surface of the fibre. Low amounts of iron, essentially Fe(II), do still penetrate the fibre.

Paper-based platforms for biological studies have received significant attention given that cellulose is ubiquitous, biocompatible, and can be readily organized into tunable fibrous structures. In the latter form, effect of complexity in surface morphologies (roughness, porosity and fiber organization) on cell-substrate interaction has not been thoroughly explored. We infer that altering the properties of a fibrous material should lead to significant changes in cellular microenvironment and direct the deposition of structurally analogous extracellular matrix (fiber-fiber templating) like collagen. Here, we elucidate the effect of varying paper roughness and surface chemistry on NIH/3T3 fibroblasts via organization of excreted collagen. Collagen intensity was found to increase linearly with paper porosity, indicating a 3D culture platform. The intensity, however, decays over time due to biodegradation of the substrate. Stability can be improved by introducing fluorinated alkyl silanes to yield hydrophobic paper. This process concomitantly transforms the substrate to a 2D-like scaffold where collagen is predominantly assembled on the surface, thus changing the cellular microenvironment. Altering surface energy also led to fluctuations in collagen intensity and organization over time for smooth (calendered) paper substrates. We infer that the increased roughness improves collagen adsorption through capillary driven petal effect. In general, the influence of the substrate simultaneously affects its ability to host collagen and guide orientation. These findings offer insights into the effects of secondary structures and chemistry of fibrous polymeric materials on cell culture, which we propose as vital parameters when using paper-based platforms.

This paper reports the fabrication of capacitive humidity sensors by integrating a graphene oxide sensing layer inside paper substrates. Graphene oxide sheets were self-assembled on the papers’ fibers. A comparative study between several sensors with different concentrations of graphene oxide and different processing times in the graphene oxide suspension is reported. Its aim is to optimize the sensing layer in terms of concentration and thickness towards the fabrication of highly sensitive and porous sensors. The morphology of the fabricated sensors was characterized using scanning electron microscopy, their structure and chemical composition using Raman and infrared spectroscopies. The washability and mechanical strength of the graphene oxide coated paper were tested in water and in an ultrasonic bath. Last, the sensing capabilities of the fabricated devices were tested for a relative humidity ranging from 30% to 90% RH. The optimal sensor is highly porous, hydrophobic and exhibits a good response towards humidity with a low hysteresis. This work presents a low cost alternative for the use of polymers and coated-papers as substrates for flexible electronics. It is also a first step towards the integration of flexible electronics into substrates, which enables the fabrication of highly porous, economical and flexible devices ideal for air flow monitoring, e-dressings and e-textiles.

Biopolymers and their composites were added during the formation of unbleached Kraft bagasse pulp paper sheets to improve the mechanical strength properties of the produced hand sheets. The biopolymers (cellulose, chitosan, and chitosan-cellulose composite) were either crosslinked or noncrosslinked and they were added in series of concentrations from 0.1% to 1.5%. The characterization of the samples using the Fourier transform infrared (IR) technique identified differences in the intensities of the characteristic IR absorption bands for chitosan, cellulose, and their composites, these differences are due to the various degrees of hydrogen bonding. The surface morphology of the biopolymers composites and the treated paper sheets were studied using SEM technique. Both the equilibrium moisture sorption and the diffusion coefficient of the paper sheets containing 1% additives were evaluated at regular time intervals. The long-term stability of the treated paper with biopolymers was verified by exposing the treated and the untreated sheets to hygrothermal ageing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40761.

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International audience; Flexible and lightweight printed thermoelectric devices are becoming increasingly attractive with the advent of ubiquitous sensing and within the context of an increasing energy demand and the associated environmental issues. In this study, flexible thermoelectric devices based on efficient solution-processed organic/hybrid thermoelectric materials have been successfully patterned. The n-type component hexylammonium titanium disulfide (TiS2(HA)x) nanocomposite reaches a ZT of 0.08 ± 0.06 at room temperature and was successfully printed on a flexible substrate using inkjet technology which yielded a functional device. The device operates in a near-ambient temperature range and retains its performance under mechanical bending, demonstrating thus the flexible properties of the device.

The degradation kinetics of ancient and model plasticized PVC films placed in contact with silk paper as wrapping material used for PVC heritage objects was investigated during an artificial thermal aging consisting in a temperature cycle and under controlled relative humidity. The studied PVC had close plasticizer content at the beginning of the artificial aging treatment and both contain a phthalate plasticizer. As reference, the same materials were aged in absence of any contact material. Color changes, plasticizers loss and surfaces properties were assessed every month. The results show that the silk paper does not accelerate the PVC degradation rate. Indeed, color changes and plasticizer loss are similar whether the contact material is present or not. However for both PVC, the silk paper slows down the migration of an additive. Even if these additives are present in a very low proportion, their migration modifies significantly the material aspect as they accumulate at the PVC surface. The silk paper has thus a protective effect during the storage of PVC objects. In addition, this study shows that the speed of aging of the ancient PVC is faster than that of the model PVC, revealing the role of the initial state of degradation.

Water-based inks were formulated using cellulose nanofibers as a binder in order to directly front/reverse print lithium ion cells on a paper separator. Moreover, the high cohesion of electrodes as provided by cellulose nanofibers allowed for the embedding metallic current collectors in the electrodes during the printing stage, in order to develop a one-step printing and assembling process. Positive and negative inks based on LiFePO4, or graphite, respectively, and cellulose nanofibers, displayed rheological properties complying with a variety of printing processes, as well as with screen printing. Printed cells exhibited high electrical conductivity and adhesion between current collectors and inks, i.e., up to 64 &plusmn, 1 J/m2. Electrochemical cycling tests at C/10 showed a reversible capacity during the first cycle of about 80 mAh/g, which slightly decayed upon cycling. Preliminary results and assembling strategies can be considered as promising, and they represent a quick solution for the manufacturing of lithium ion batteries. Work is in progress to improve these processing issues and the cycling performances of Li-ion cells.

This contribution unveils and defines the concept of covalent printing onto cellulose paper through the support of a simple and efficient strategy. A photoresponsive cellulose paper bearing disulfide functional groups was created as a molecular printboard for spatio-temporal writing through thiol-X ligation of functional inks upon light irradiation. This strategy using molecular inks in a modular way culminated with the creation of patterns with a high resolution. Hidden covalent writing to the naked eyes was developed through the use of coumarin-based inks while the use of colored inks containing a rhodamine backbone established an uncovered pH-responsive covalent printing, both strategies can potentially find applications in the formation of anti-counterfeiting devices.

Composite nanocoating of cationic polyacrylamide and aqueous dispersion of hydroxyl-functionalized carbon nanotubes (CNTs) with pre-adsorbed alkali lignin on lignocellulose wood microfibers has been developed to produce lightweight, flexible, and electrically conductive paper sheets from a simple, low-cost, and well-established papermaking process. Electron microscopy and Fourier transform infrared spectroscopy revealed the formation of strong interfacial hydrogen bonding between the oxygen-containing functional groups on the CNT surfaces and the hydroxyl groups of the cellulose microfibers. As a result, the mechanical properties of the papers with CNT content as low as 2.5 wt% were greatly improved compared to the pristine materials, with up to 10, 55, and 422% increases in tensile strength, internal bonding strength, and wet strength retention, respectively. The multifunctional sensing behavior of the CNT–cellulose composite papers to tensile strain and liquid water was examined comprehensively. Results show that these papers have superior tensile strain sensitivity compared to conventional foil gauges. Moreover, the water-induced electrical resistance changes can be tailored by the paper composition and resistance variations of more than three orders of magnitude were achieved without any degradation of the sensing performance through cycling. These smart papers provide a low-cost and renewable alternative to petrochemical-based materials for portable electronics and sensing applications.

International audience; Laser cutting of paper is widely used in the paper conversion industry. CO 2 lasers are well suited for this type of applications. Desktop printing is a large market both for digital photography, document management and graphics applications, but it still lacks advanced cutting and scoring ability, and CO 2 lasers seem costly to be integrated in mass-market printers. For that reason, mass-scalable and low-cost semiconductor laser diodes would be very advantageous to add paper cutting and scoring features in desktop printers. However, common paper can not be cut properly using visible or Near Infrared (NIR) laser diode since it has a very poor absorption at these wavelengths. We report here an innovative solution to achieve paper cutting or scoring using a 1 W single emitter NIR laser diode, within an inkjet printer. A special ink that absorbs the NIR light, and that penetrates all through the paper, is first disposed on the lines to be cut. Then, the laser diode goes along the lines to be cut. We show that a cutting speed of 2m/min can be achieved on 80g/m 2 conventional paper. The influence of the optical properties of the ink on the cutting speed are discussed, as well as focussing issues. In particular, we show that invisible inks are suitable, and very clear-cut edges can be obtained. The perspective of this technique are discussed.

Melamine impregnated paper offcuts and waste has been shown to be usable both directly, in finely powdered form, as a binder for particle board and as a melamine substitute during the formulation and preparation of liquid MUF resins. Both approaches were based on the residual activity of the MF resin present in the resin. Amounts of waste melamine paper of 22% on dry wood, equivalent to 10% melamine resin solids on total dry panel weight, were shown necessary for water resistant particleboard, and 18.5% for interior particleboard. Due to problems connected to excessive viscosity increase only a maximum of 25% of the total melamine in the formulated melamine resin could be substituted to good effect in the formulation of liquid MUF resin adhesives.

International audience; Cellobiose, a dimer of glucose wearing a glycosidic bond as in cellulose, was used as model molecule to understand the chemical degradation pathways taking place in iron gall inks impregnated papers. Experiments were carried out in liquid phase at 80 degrees C to study the effects of pH and of the presence of iron and oxygen on the cleavage of the glycosidic bond. Capillary electrophoresis was used to quantitatively follow the cellobiose degradation and the formation of glucose. Attenuated total reflectance infrared spectroscopy of freeze-dried samples was done to identify the presence of secondary products of reaction. UV-Visible spectroscopy allowed monitoring the iron(II) and iron(III) contents as a function of time and pH. The data reveal that the simultaneous presence of iron and oxygen enhances the degradation of cellobiose. Nevertheless, even if some oxidation of the sugar molecules occurs, the predominant pathway of cellobiose decomposition is found to be acid-catalyzed hydrolysis due to the high acidity of the medium generated from the oxidation and precipitation of iron.

Comments on the paper 'Flow regime and liquid-solid mass transfer investigation in a designed porous structure using electrochemical micro-probes' by Altheimer et al. (2016)

This work reports the charge storage ability of NixCo1-x(OH)2 nanosheet-carbon nanofoam paper (CNFP) composites prepared by electrodeposition for high areal capacity supercapacitor electrodes. The NixCo1-x(OH)2 film grew through instantaneous nucleation, uniformly covered CNFP, and displayed a porous morphology composed of a nanosheet percolation network. The electrochemical response of the NixCo1-x(OH)2 films was tuned by varying the Co to Ni ratios. The optimized NixCo1-x(OH)2 stoichiometry resulted in Ni0.33Co0.67(OH)2-CNFP electrodes displaying areal capacity/capacitance values of 1.52 C cm−2/2.03 F cm−2 at 2.1 mA cm−2, resulting from the contribution of the double layer capacity of CNFP with the redox capacity of NixCo1-x(OH)2. A two electrode cell composed of CNFP as negative electrode and NixCo1-x(OH)2-CNFP as positive electrode presented a high areal capacity value of 0.73 C cm−2 at 7.2 mA cm−2.

A new approach exploiting the dual properties of thiol-grafted cellulose paper for promoting copper-catalyzed [3+2]-cycloadditions of organic azides with alkynes and adsorbing residual copper species in solution was developed. The thiol-grafted cellulose paper, used as a paper strip, effects the reduction of Cu-II to catalytically active Cu-I and acts as a powerful adsorbent for copper, thereby facilitating the work-up process and leaving the crude mixture almost free of copper residues after a single filtration.

International audience; Iron gall inks (IGI) were largely used for writing until the nineteenth century. Under certain circumstances, they provoke a substantial degradation of their cellulosic support.It was shown in a previous works thatc ombination of oxygen and iron largely impacts cellulose chain breaking occurring in acidic conditions (pH 3–4). The present study aims to study the kinetic of this degradation. It assesses the validity of Arrhenius law between 20 and 90°C taking advantage of the fast depolymerization of IGI impregnated papers at room temperature and using two complementary tools: DP measurements and zero-span tensile strength. The first one is sensitive enough to measure degradation at its very beginning, while the second is more appropriate for advanced stage of degradation. Similar activation energies (97± 2 kJ mol-1) were found viaDP and zero-span measurements, and reaction rates of IGI impregnated papers were 1–2 orders of magnitude aboveavailable data related to lignin-free acidic papers. These observations suggest a dominant hydrolytic mechanismthat involves directly or indirectly oxygen and iron.

This paper describes the design and fabrication of electrically controlled paper actuators that operate based on the dimensional changes that occur in paper when the moisture absorbed on the surface of the cellulose fi bers changes. These actuators are called “Hygroexpansive Electrothermal Paper Actuators” (HEPAs). The actuators are made from paper, conducting polymer, and adhesive tape. They are lightweight, inexpensive, and can be fabricated using simple printing techniques. The central element of the HEPAs is a porous conducting path (used to provide electrothermal heating) that changes the moisture content of the paper and causes actuation. This conducting path is made by embedding a conducting polymer (PEDOT:PSS) within the paper, and thus making a paper/polymer composite that retains the porosity and hydrophilicity of paper. Different types of HEPAs (straight, precurved, and creased) achieved different types of motions (e.g., bending motion, accordion type motion). A theoretical model for their behavior is proposed. These actuators have been used for the manipulation of liquids and for the fabrication of an optical shutter.

This work focuses on the use of Ru(0) nanoparticles as heterogeneous catalyst for ozone decomposition and radical production. In a first set of experiments, the nanoparticles have been deposited on two inorganic supports (TiO2 or SiO2) by a wet impregnation approach. This study confirmed the high potential of Ru nanoparticles as active species for ozone decomposition at pH 3, since the ozone half-life time decreases by a factor 20–25, compared to the reference experiment carried out without any catalyst. The enhancement of the ozone decomposition kinetics provided an improved radical production and a higher transient radical concentration in a shorten ozone exposure. Consequently, lower oxidant dosage and contact time would be necessary. Thus, very significant atrazine consumption kinetics enhancements were measured. In a second set of experiments, a non-woven fiber paper composed of a TiO2/SiO2/zeolite mixture has been evaluated as an original support for ruthenium nanoparticles. Even if lower ozone decomposition kinetics was observed compared to TiO2 or SiO2, this support would be a promising alternative to inorganic powders to avoid the catalyst recovery step and to design reactors such as tubular reactors. A new numerical procedure is presented for the evaluation of the transient HO concentration and of the Rct.

The fabrication process of anodic aluminium oxide (AAO) on a paper-based substrate is challenging because the use of a highly economical, conformable and ecological substrate. This process is based on a simple, cost-effective, self-ordering anodization of aluminium, which yields a vertically aligned and a highly ordered nanoporous structure. The manufacturing process on a flexible substrate with the use of phosphoric acid is described, and a capacitive sensor produced on this layer is investigated versus the humidity concentration and the frequency. The AAO morphology and the structure obtained were analysed, and the electrical properties of the sensing layer were investigated, using a 4192A LF network analyser in a climatic chamber. The surface conduction mechanism and the effect of humidity on the dielectric properties of a porous anodic aluminium oxide are discussed.

International audience; An efficient and practical procedure for the free α-carboxylic acid esterification of amino acid residues with β-(trimethyl- silyl)ethoxymethyl chloride and triisopropylsilyl chloride is described. The reaction takes place under mild conditions and the expected protected amino acids are obtained in good to excellent yields. Our method provides a useful alternative for the C-terminal carboxylic acid protection of amino acids and peptides. Moreover, the removal of such protection was also achieved under mild condi- tions, without affecting either the other protecting groups at the α- amino moiety and side chains or the optical integrity at the α-posi- tion of the amino acid residues. Examples of their use in peptide synthesis are also illustrated.

Recent work showed that carbon nanotubes could be fabricated into bucky-paper structures as self-supporting membranes and their hydrophobic property used for water desalination by membrane distillation. Carbon nanotube bucky-papers possess very interesting properties such as natural hydrophobicity, high porosity and very high specific surface area, making of them promising candidates for separation applications. However, to inhibit crack formation associated with poor mechanical stability, improved durability structures that retain a high degree of hydrophobicity need to be developed. In this work we chemically modified high purity carbon nanotubes by (i) UV/ozone treatment to create hydroxyl groups and (ii) reacting those groups by substitution with alkoxysilane based groups. The resulting nanotubes presented a silicon content up to 2.5% and the bucky-papers produced had larger contact angle (140° compared to 125°) and liquid entry pressures. We report here on their fabrication and use as membranes in direct contact membrane distillation.

Paper, mainly constituted of cellulose fibres, often contains mineral fillers. These fillers increase some of the properties of the paper (whiteness, printability, etc.) and are cheaper than the cellulose fibres. Nevertheless, the fillers reduce the mechanical properties of the sheet. Paper presents an anisotropy corresponding to three main directions. This anisotropy characterises the sheet mechanical properties, structure and filler distribution. Analyses of the cross section of the paper sheet with a low-vacuum scanning electron microscope with an energy dispersive spectrometer analysis module can show this distribution. The procedure developed consists in analysing discrete profiles to build the mean profile known as filler Z-distribution for each of the fillers. To develop this method, problems such as determination of the surface points, the number of points to analyse to define a cross section profile and the time required for the test, have been solved. Paper is sensitive to electron irradiation. In order to avoid deterioration of the material and to obtain satisfactory results, the time span for analyses is restricted to 40 s with a 12 kV electron beam accelerating voltage. Monte Carlo simulations are used to determine the diffusion cloud size and thus to determine the number of points that constitute a profile. The samples are gold sputtered and, with the aid of backscattered imaging, the coated surface allows determination of the sample surface points.

Photocatalytic oxidation of two ketones, acetone, and 2-butanone, over TiO 2 -containing paper was studied under two different levels of relative humidity. Adsorption of these ketones on TiO 2 -containing paper is significantly affected by the presence of water vapor. Adsorption isotherms of both acetone and 2-butanone, under dry and humid atmosphere, can be satisfactory described using the Langmuir adsorption model for concentrations ranging from 0 to 6 g m −3 . Kinetic data of the photocatalytic oxidation of these ketones are analyzed using the Langmuir–Hinshelwood model except for the photocatalytic oxidation of acetone in humid air conditions where adsorption was assumed to be the rate limiting step. In the case of acetone, photoactivity is greatly inhibited in presence of water vapor. On the other hand, it is showed that water vapor has little effect on 2-butanone photocatalytic degradation. The latter is just slightly improved in humid air conditions for initial 2-butanone concentrations upper than 2 g m −3 . An explanation is given in term of adsorption affinity of the pollutants compared with competitive adsorption of water molecules with the ketones onto TiO 2 -containing paper.

An approach to the analysis of the impedance of porous electrodes proposed by Barcia et al. [Electrochim. Acta 47 (2002) 2109] is reconsidered. It is pointed out that the impedance data are not sufficient to determine pore length (l) pore radius (r) and number of pores (n), since their analysis can only yield two combinations of these geometrical parameters: nr3/2 and l r . However, if one of the geometrical parameters l, r or n is known from an independent measurement, the impedance data can provide the information for estimating the others.

International audience; no abstract

International audience

Oxidation reactions that involve several oxygen and nitrogen reactive species together with nucleobase radical cations give rise among various classes of lesions to modified bases. About 70 of oxidized nucleosides that include diastereomeric forms have been characterized in mechanistic studies involving isolated DNA and related model compounds. However, only eight modified bases have been accurately measured within cellular DNA upon exposure to either gamma or UVA radiations. Emphasis is placed in this survey on recent developments of HPLC associated with tandem mass spectrometry (MS/MS) operating in the mild electrospray ionization mode. Interestingly, the HPLC-MS/MS assay in the multiple reaction monitoring mode appears to be the more sensitive and accurate method currently available for singling out several oxidized nucleosides including 8-oxo-7,8-dihydro-2'-deoxyguanosine, 8-oxo-7,8-dihydro-2'-deoxyadenosine, 5-formyl-2'-deoxyuridine, 5-(hydroxymethyl-2'-deoxyuridine, 5-hydroxy-2'-deoxyuridine, and the four diastereomers of 5,6-dihydroxy-5,6-dihydrothymidine within isolated and cellular DNA. However, one limitation of the assay that also applied to all chromatographic methods is the slight side-oxidation of normal bases during DNA extraction and subsequent work-up. This explains why the combined use of DNA repair glycosylases with either the comet assay or the alkaline elution technique is a better alternative to monitor the formation of low levels of oxidized bases within cellular DNA.