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The fabrication of all solid-state 3D micro-supercapacitor is challenging for powering connected and miniaturized emerging electronics devices in the frame of the future Internet of Things paradigm. Here we highlight the design of a specific solid electrolyte based on ethylmethylimidazolium bis(trifluoromethanesulfonate)imide confined within polyvinylidenefluoride which enables to meet the requirements of safety, easy packaging, and leakage free 3D micro-supercapacitors. This ionogel-based microdevice (2 mm × 2 mm footprint area) exhibits good cycling stability over 30 000 cycles with an areal energy density of 4.4 µWh.cm-2 and a power density of 3.8 mW.cm-2. It can also sustain the high temperature reflow soldering process (~250 °C-5 min) without damage, which is performed to directly bond surface mounted miniaturized devices onto printed circuit boards. This strategy not only provides a reference for the design of high-performance 3D interdigitated micro-supercapacitors, but also paves the way to their further implementation in miniaturized electronic chips for Internet of Things applications. [ABSTRACT FROM AUTHOR]

Solid ionogel electrolytes are rather competitive compared to liquid carbonate based electrolyte regarding ionic conductivity but they show much better safety. It is striking that the ionogels presented here are obtained within few minutes by UV curing which triggers the formation of the polymer host network confining N-methyl,N-propylpyrrolidinium bis-(trifluoromethyl)sulfonylimide with lithium bis-(trifluoromethyl)sulfonylimide salt at the concentration of 1M. This fast and easy process allows for obtaining all-solid like micro-batteries. Herein the effect of mesh size and ethylene oxide content of various host networks is deciphered. An optimum balance between mesh size, ethylene oxide and lithium content is identified. The ionogel formed from trimethylolpropane ethoxylate triacrylate and 1,6-hexanediol diacrylate confining 90% wt of ionic liquid shows a mesh size close to 5 nm, with an enhanced fragility of the confined ionic liquid, as referred to that of the bulk one. Along with these last features, its ethylene oxide content allows a very good lithium ion diffusion. At room temperature and at C/5 cycling rate, prototype batteries LiFePO4 ionogel Li metal battery can restitute 70% of the initial capacity during up to 1200 cycles. [ABSTRACT FROM AUTHOR]

Ionogels based on in situ crosslinking of chitosan in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIm Ac) are synthesized, and studied from macroscopic properties to preferred interactions at the host matrix/EMIm Ac interface. It is highlighted that the imidazolium cations of the ionic liquid (IL) show preferred interactions with the chitosan host matrix. This exemplifies how the confinement of ILs, through an interface effect, can induce the breakdown of aggregated regions found systematically in bulk ILs and can increase the fragility of ILs. These biopolymer based ionogels could find application as biosensors and in the field of energy. [ABSTRACT FROM AUTHOR]

Confining ionic liquids (ILs) with added lithium salt within silica host networks enhances their fragility and improves their conductivity. Overall, conductivity measurements, Raman spectroscopy of the TFSI anion and NMR spectroscopy of the lithium cation show segregative interaction of lithium ions with the SiO2 host matrix. This implies at IL/SiO2 interfaces a breakdown of aggregated regions that are found systematically in bulk ILs. Such destructuration due to the interface effect determines the fragility and thus results locally at the interface in short relaxation times, low viscosity, and good ionic conductivity. The “destructuration” of ion pairs or domains makes ILs within ionogels a competitive alternative to existing solid ionic conductors in all-solid devices, such as lithium batteries and supercapacitors. [ABSTRACT FROM AUTHOR]

We have developed flexible polymer-gel electrolytes based on a polyacrylate cross-linked matrix that confines an ionic liquid doped with a lithium salt. Free-standing solid electrolyte membrane is obtained after UV photo-polymerization of acrylic monomers dissolved inside the ionic liquid/lithium salt mixture. The liquid precursor of the photo-ionogel may also be directly deposited onto porous composite electrode, which results in all-solid state electrode/electrolyte stacking after UV illumination. Minor variations in the polymer component of the electrolyte formulation significantly affect the electrochemical behavior in LiFePO 4 /lithium and lithium/lithium cells. The rate performance increases with an increase of the ionic conductivity, which decreases with the polymer content and decreases with increasing oxygen content in the polyacrylate matrix. Their fairly low modulus endow them weak and beneficial pressure-sensitive-adhesive character. X-Rays Tomography shows that the solid-state photo-ionogel electrolytes keep their integrity upon cycling and that their surface remains smooth. The coulombic efficiency of LiFePO 4 /lithium cells increases with an increase of the adhesive strength of the photo-ionogel, suggesting a relationship between the contact intimacy at the lithium/photo-ionogel interface and the efficiency of the lithium striping/plating. In lithium/lithium cells, only the photo-ionogels with the higher adhesion strength are able to allow the reversible striping/plating of lithium. [ABSTRACT FROM AUTHOR]

This work demonstrates ink-jet printed LiFePO 4 -based composite porous electrodes for microbattery application. As binder and dispersant, we found that aqueous inks with more suitable rheological properties with respect to ink-jet printing are prepared with the low molecular weight poly-acrylic-co-maleic acid copolymer, rather than with the carboxymethyl cellulose standard binder of the lithium-ion technology. The ink-jet printed thin and porous electrode shows very high rate charge/discharge behavior, both in LiPF 6 /ethylene carbonate-dimethyl carbonate (LP30) and lithium bis(trifluoromethane)sulfonylimide salt (Li-TFSI) in N-methyl-N-propylpyrrolidinium bis(trifluoromethane)suflonylimide ionic liquid (PYR13-TFSI) electrolytes, as well as good cyclability. [ABSTRACT FROM AUTHOR]

Ink-jet printing of ionogel for low-cost microbattery is presented. Such an approach allows to provide liquid-like electrolyte performances for all-solid microdevices. Ink-jet printing process is possible thanks to sol precursor of the ionogel. This full silica based ionogels confining ionic liquid are known to be thermal resistant, serving safety and technologies requiring solder reflow. High ionic conductivity and compatibility with porous composite electrodes allow reaching good electrochemical cycling performance: full Li-ion cell with LiFePO 4 and Li 4 Ti 5 O 12 porous composite electrodes shows a surface capacity of 300 μAh cm −2 for more than 100 cycles. Such surface capacities are very competitive as compared to those obtained for microdevices based on expensive PVD processes. [ABSTRACT FROM AUTHOR]

In this work we have investigated the charge storage mechanism of MnO 2 electrodes in ionic liquid electrolytes. We show that by using an ionic liquid with a cation that has the ability to form hydrogen bonds with the active material (MnO 2) on the surface of the electrode, a clear faradaic contribution is obtained. This situation is found for ionic liquids with cations that have a low pKa, i.e. protic ionic liquids. For a protic ionic liquid, the specific capacity at low scan rate rates can be explained by a densely packed layer of cations that are in a standing geometry, with a proton directly interacting through a hydrogen bond with the surface of the active material in the electrode. In contrast, for aprotic ionic liquids there is no interaction and only a double layer contribution to the charge storage is observed. However, by adding an alkali salt to the aprotic ionic liquid, a faradaic contribution is obtained from the insertion of Li+ into the surface of the MnO 2 electrode. No effect can be observed when Li+ is added to the protic IL, suggesting that a densely packed cation layer in this case prevent Li-ions from reaching the active material surface. • Hydrogen bonding between MnO 2 and an IL cation important for charge storage. • A faradaic contribution from MnO 2 is observed with a protic IL, due to a redox reaction. • Capacity explained by a densely packed layer of standing cations on the surface. • For aprotic ILs only double layer charge storage is observed. [ABSTRACT FROM AUTHOR]

We use molecular dynamics calculations to investigate the behavior of metal cations (Li, Na and Zn) within ionic liquids (ILs), specifically EMIM-TFSI, and their impact on key properties, particularly focusing on ion-ion correlations and their influence on diffusion and conductivity. The study explores the competition between metal cations and EMIM ions for binding to TFSI and analyzes ion pair dynamics, revealing that metal cation-TFSI pairs exhibit significantly longer lifetimes compared to TFSI-EMIM pairs. This competitive interaction and the increased stability of metal cation-TFSI pairs at higher concentrations leads to reduced ion exchange, resulting in decreased diffusion and conductivity. The observations underscore the importance of ion size and charge in determining their behavior regarding IL dynamics. Overall, this work provides valuable insights for designing ILs with customized properties, particularly in the context of optimizing conductivity and addressing energy storage challenges.

Ionic liquid (IL)-based gels (ionogels) have received considerable attention due to their unique advantages in ionic conductivity and their biphasic liquid-solid phase property. In ionogels, the negligibly volatile ionic liquid is retained in the interconnected 3D pore structure. On the basis of these physical features as well as the chemical properties of well-chosen ILs, there is emerging interest in the anti-bacterial and biocompatibility aspects. In this review, the recent achievements of ionogels for biomedical applications are summarized and discussed. Following a brief introduction of the various types of ILs and their key physicochemical and biological properties, the design strategies and fabrication methods of ionogels are presented by means of different confining networks. These sophisticated ionogels with diverse functions, aimed at biomedical applications, are further classified into several active domains, including wearable strain sensors, therapeutic delivery systems, wound healing and biochemical detections. Finally, the challenges and possible strategies for the design of future ionogels by integrating materials science with a biological interface are proposed.

Silicon-containing Li-ion batteries have been the focus of many energy storage research efforts because of the promise of high energy density. Depending on the system, silicon generally demonstrates stable performance in half-cells, which is often attributed to the unlimited lithium supply from the lithium (Li) metal counter electrode. Here, the electrochemical performance of silicon with a high voltage NMC622 cathode was investigated in superconcentrated phosphonium-based ionic liquid (IL) electrolytes. As a matter of fact, there is very limited work and understanding of the full cell cycling of silicon in such a new class of electrolytes. The electrochemical behavior of silicon in the various IL electrolytes shows a gradual and steeper capacity decay, compared to what we previously reported in half-cells. This behavior is linked to a different evolution of the silicon morphology upon cycling, and the characterization of cycled electrodes points toward mechanical reasons, complete disconnection of part of the electrode, or internal mechanical stress, due to silicon and Li metal volume variation upon cycling, to explain the progressive capacity fading in full cell configuration. An extremely stable solid electrolyte interphase (SEI) in the full Li-ion cells can be seen from a combination of qualitative and quantitative information from transmission electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and magic angle spinning nuclear magnetic resonance. Our findings provide a new perspective to full cell interpretation regarding capacity fading, which is oftentimes linked almost exclusively to the loss of Li inventory but also more broadly, and provide new insights into the impact of the evolution of silicon morphology on the electrochemical behavior.

The latest advances in the stabilization of Li/Na metal battery and Li-ion battery cycling have highlighted the importance of electrode/electrolyte interface [solid electrolyte interphase (SEI)] and its direct link to cycling behavior. To understand the structure and properties of the SEI, we used combined experimental and computational studies to unveil how the ionic liquid (IL) cation nature and salt concentration impact the silicon/IL electrolyte interfacial structure and the formed SEI. The nature of the IL cation is found to be important to control the electrolyte reductive decomposition that influences the SEI composition and properties and the reversibility of the Li-Si alloying process. Also, increasing the Li salt concentration changes the interface structure for a favorable and less resistive SEI. The most promising interface for the Si-based battery was found to be in P 1222 FSI with 3.2 m LiFSI, which leads to an optimal SEI after 100 cycles in which LiF and trapped LiFSI are the only distinguishable lithiated and fluorinated products detected. This study shows a clear link between the nanostructure of the IL electrolyte near the electrode surface, the resulting SEI, and the Si negative electrode cycling performance. More importantly, this work will aid the rational design of Si-based Li-ion batteries using IL electrolytes in an area that has so far been neglected, reinforcing the benefits of superconcentrated electrolyte systems.

Polysaccharides have received a lot of attention in biomedical research for their high potential as scaffolds owing to their unique biological properties. Fibrillar scaffolds made of chitosan demonstrated high promise in tissue engineering, especially for skin. As far as bone regeneration is concerned, curdlan (1,3-β-glucan) is particularly interesting as it enhances bone growth by helping mesenchymal stem cell adhesion, by favoring their differentiation into osteoblasts and by limiting the osteoclastic activity. Therefore, we aim to combine both chitosan and curdlan polysaccharides in a new scaffold for bone regeneration. For that purpose, curdlan was electrospun as a blend with chitosan into a fibrillar scaffold. We show that this novel scaffold is biodegradable (8% at two weeks), exhibits a good swelling behavior (350%) and is non-cytotoxic in vitro. In addition, the benefit of incorporating curdlan in the scaffold was demonstrated in a scratch assay that evidences the ability of curdlan to express its immunomodulatory properties by enhancing cell migration. Thus, these innovative electrospun curdlan-chitosan scaffolds show great potential for bone tissue engineering.

In the frame of the development of solid ionogel electrolytes with enhanced ion transport properties, this paper investigates ionogel systems constituted by ∼80 wt% of ionic liquids (ILs) confined in meso-/macroporous silica monolith materials. The anion-cation coordination for two closely related ILs, either aprotic (AIL) butylmethylpyrrolidinium or protic (PIL) butylpyrrolidinium, both with bis(trifluoromethylsulfonyl)imide (TFSI) anions, with and without lithium cations, is studied in depth. The ILs are confined within silica with well-defined mesoporosities (8 to 16 nm). The effects of this confinement, onto melting points, onto conductivity followed by impedance spectroscopy, and onto lithium-TFSI coordination followed by Raman spectroscopy, are presented. Opposite effects have been observed on the melting temperature: it increased for the AIL (+2 °C) upon confinement, while it decreased for the PIL (-2 °C). With lithium, the confinement led to an increase of the melting temperature (+1 °C) for the PIL and AIL. Regarding ionic conductivities, a relative maximum was observed at 40 °C for a mesopore diameter of 10 nm for the AIL with 0.5 M lithium, while it was not clearly visible for the PIL. These differences are discussed in view of the charge balance at the interface between silanols and ILs: the presence of a PIL, contrary to an AIL, is expected to modify the acidity of the silica. Raman data showed that the coordination number of lithium by TFSI is reduced upon AIL confinement, although this was not observed for PILs. At last, this work highlights the impact of the acidity of a PIL on the chemistry occurring at the interface of the host network within ionogels.

Hydroxyapatite (HA) has received much interest for being used as bone substitutes because of its similarity with bioapatites. In form of nanowires or nanotubes, HA would offer more advantages such as better biological and mechanical properties than conventional particles (spherical). To date, no study had allowed the isolated nanowires production with simultaneously well-controlled morphology and size, narrow size distribution and high aspect ratio (length on diameter ratio). So, it is impossible to determine exactly the real impact of particles' size and aspect ratio on healing responses of bone substitutes and characteristics of these ones; their biological and mechanical effects can never be reproducible. By the template-assisted pulsed electrodeposition method, we have for the first time succeeded to obtain such calcium-deficient hydroxyapatite (CDHA) particles in aqueous baths with hydrogen peroxide by both applying pulsed current density and pulsed potential in cathodic electrodeposition. After determining the best conditions for CDHA synthesis on gold substrate in thin films by X-ray diffraction (XRD) and Energy dispersive X-ray spectroscopy (EDX), we have transferred those conditions to the nanowires and nanotubes synthesis with high aspect ratio going until 71 and 25 respectively. Polycrystalline CDHA nanowires and nanotubes were characterized by Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). At the same time, this study enabled to understand the mechanism of nanopores filling in gold covered polycarbonate membrane: here a preferential nucleation on gold in membranes with 100 and 200 nm nanopores diameters forming nanowires whereas a preferential and randomly nucleation on nanopores walls in membranes with 400 nm nanopores diameter forming nanotubes., (Copyright © 2018. Published by Elsevier B.V.)

As our understanding of the physiopathology of intervertebral disc (IVD) degeneration has improved, novel therapeutic strategies have emerged, based on the local injection of cells, bioactive molecules, and nucleic acids. However, with regard to the harsh environment constituted by degenerated IVDs, protecting biologics from in situ degradation while allowing their long-term delivery is a major challenge. Yet, the design of the optimal approach for IVD regeneration is still under debate and only a few papers provide a critical assessment of IVD-specific carriers for local and sustained delivery of biologics. In this review, we highlight the IVD-relevant polymers as well as their design as macro-, micro-, and nano-sized particles to promote endogenous repair. Finally, we illustrate how multiscale systems, combining in situ-forming hydrogels with ready-to-use particles, might drive IVD regenerative medicine strategies toward innovation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Discogenic low back pain is considered a major health concern and no etiological treatments are today available to tackle this disease. To clinically address this issue at early stages, there is a rising interest in the stimulation of local cells by in situ injection of growth factors targeting intervertebral disc (IVD) degenerative process. Despite encouraging safety and tolerability results in clinic, growth factors efficacy may be further improved. To this end, the use of a delivery system allowing a sustained release, while protecting growth factors from degradation appears of particular interest. We propose herein the design of a new injectable biphasic system, based on the association of pullulan microbeads (PMBs) into a cellulose-based hydrogel (Si-HPMC), for the TGF-β1 and GDF-5 growth factors sustained delivery. We present for the first time the design and mechanical characterization of both the PMBs and the called biphasic system (PMBs/Si-HPMC). Their loading and release capacities were also studied and we were able to demonstrate a sustained release of both growth factors, for up to 28 days. Noteworthy, the growth factors biological activity on human cells was maintained. Altogether, these data suggest that this PMBs/Si-HPMC biphasic system may be a promising candidate for the development of an innovative bioactive delivery system for IVD regenerative medicine.

Drug delivery systems are proposed for the in situ controlled delivery of therapeutic molecules in the scope of tissue engineering. We propose herein silica nanofibers as carriers for the loading and release of bioactive proteins. The influence of pH, time and concentration on the amount of adsorbed proteins was studied. The interactions allowing loading were then studied by means of electron microscopy, zeta potential measurements, electron energy loss spectroscopy and attenuated total reflectance Fourier transform infrared analysis. Release profiles were determined and biological activities were enzymatically assessed. The first part of the work was carried out with lysozyme as a model protein, and then bioactive growth factors TGF-β1 and GDF-5 were used because their significance in human adipose stromal cell differentiation towards intervertebral disc nucleopulpocytes was previously assessed. It is demonstrated that protein-silica nanofiber interactions are mainly driven by hydrogen bonds and local electrostatic interactions. The present data thus provide a better understanding of the adsorption phenomenon involved, as well as a method to control protein adsorption and release. It is worth pointing out that the kinetic release of growth factors, up to 28 days, and their biological activity maintenance seem to be compatible with intervertebral disc regenerative medicine.

Obtaining solid-state electrolytes with good electrochemical performances remains challenging. Ionogels, i.e. solid host networks confining an ionic liquid, are promising as they keep the macroscopic properties of the liquid. However, confinement of an ionic liquid can imply important changes in its molecular dynamics, depending on the route of synthesis and on the confining network. We studied this effect on an imidazolium based ionic liquid with its lithium salt confined in a hybrid biopolymer-silica matrix. Dynamics of bulk and confined solution was probed by quasi-elastic neutron scattering (QENS) which revealed a weakly slowed dynamics of imidazolium-based ionic liquid inside the polymer-silica host network.

GY785 is an exopolysaccharide produced by a mesophilic bacterial strain Alteromonas infernus discovered in the deep-sea hydrothermal vents. GY785 highly sulfated derivative (GY785 DRS) was previously demonstrated to be a promising molecule driving the efficient mesenchymal stem cell chondrogenesis for cartilage repair. This glycosaminoglycan- (GAG-) like compound was modified in a classical solvent (N,N'-dimethylformamide). However, the use of classical solvents limits the polysaccharide solubility and causes the backbone degradation. In the present study, a one-step efficient sulfation process devoid of side effects (e.g., polysaccharide depolymerization and/or degradation) was developed to produce GAG-like derivatives. The sulfation of GY785 derivative (GY785 DR) was carried out using ionic liquid as a reaction medium. The successful sulfation of this anionic and highly branched heteropolysaccharide performed in ionic liquid would facilitate the production of new molecules of high specificity for biological targets such as tissue engineering or regenerative medicine.

Injectable materials for mini-invasive surgery of cartilage are synthesized and thoroughly studied. The concept of these hybrid materials is based on providing high enough mechanical performances along with a good medium for chondrocytes proliferation. The unusual nanocomposite hydrogels presented herein are based on siloxane derived hydroxypropylmethylcellulose (Si-HPMC) interlinked with mesoporous silica nanofibers. The mandatory homogeneity of the nanocomposites is checked by fluorescent methods, which show that the silica nanofibres dispersion is realized down to nanometric scale, suggesting an efficient immobilization of the silica nanofibres onto the Si-HPMC scaffold. Such dispersion and immobilization are reached thanks to the chemical affinity between the hydrophilic silica nanofibers and the pendant silanolate groups of the Si-HPMC chains. Tuning the amount of nanocharges allows tuning the resulting mechanical features of these injectable biocompatible hybrid hydrogels. hASC stem cells and SW1353 chondrocytic cells viability is checked within the nanocomposite hydrogels up to 3 wt% of silica nanofibers.

The current interest in ionic liquids (ILs) is motivated by some unique properties, such as negligible vapour pressure, thermal stability and non-flammability, combined with high ionic conductivity and wide electrochemical stability window. However, for material applications, there is a challenging need for immobilizing ILs in solid devices, while keeping their specific properties. In this critical review, ionogels are presented as a new class of hybrid materials, in which the properties of the IL are hybridized with those of another component, which may be organic (low molecular weight gelator, (bio)polymer), inorganic (e.g. carbon nanotubes, silica etc.) or hybrid organic-inorganic (e.g. polymer and inorganic fillers). Actually, ILs act as structuring media during the formation of inorganic ionogels, their intrinsic organization and physicochemical properties influencing the building of the solid host network. Conversely, some effects of confinement can modify some properties of the guest IL, even though liquid-like dynamics and ion mobility are preserved. Ionogels, which keep the main properties of ILs except outflow, while allowing easy shaping, considerably enlarge the array of applications of ILs. Thus, they form a promising family of solid electrolyte membranes, which gives access to all-solid devices, a topical industrial challenge in domains such as lithium batteries, fuel cells and dye-sensitized solar cells. Replacing conventional media, organic solvents in lithium batteries or water in proton-exchange-membrane fuel cells (PEMFC), by low-vapour-pressure and non flammable ILs presents major advantages such as improved safety and a higher operating temperature range. Implementation of ILs in separation techniques, where they benefit from huge advantages as well, relies again on the development of supported IL membranes such as ionogels. Moreover, functionalization of ionogels can be achieved both by incorporation of organic functions in the solid matrix, and by encapsulation of molecular species (from metal complexes to enzymes) in the immobilized IL phase, which opens new routes for designing advanced materials, especially (bio)catalytic membranes, sensors and drug release systems (194 references).

Here we used rheological methods to study the gelation kinetics of silanized hydroxypropylmethylcellulose (HPMC-Si) hydrogel for tissue engineering. Firstly, the gelation time was determined from the independence of tan delta on frequency, and the Arrhenius law was applied to obtain the apparent activation energy of gelation, which was found to be about 109.0 kJ/mol. Secondly, the gelation process was monitored by measuring the sample storage modulus. The results showed that the gelation process could be well classified as a second-order reaction. In addition, a composite HPMC-Si/MWNTs hydrogel system for potential cartilage tissue engineering was investigated. The comparison of pure HPMC-Si hydrogel and composite HPMC-Si/MWNTs systems indicated that the addition of MWNTs could increase the mechanical strength of hydrogel without changing the gelation mechanism of the system.

SnO2 translucent monolith ionogels were obtained by a sol-gel processing using bis(2-methylbutan-2-oxy)di(pentan-2,4-dionato)tin as a precursor in the presence of various ionic liquids: [BMI][Br], [BMI][TFSI], [BMI][BF4]. The confinement of ionic liquids within the gels was evidenced by Differential Scanning Calorimetry, FTIR and FT-Raman spectroscopy. The ionic liquids could be efficiently washed off, which resulted in supermicroporous solids. Calcination in air at 550 degrees C of the dried monoliths resulted in nanoporous nanocrystalline cassiterite tin dioxide particles with crystallite sizes of about 8-12 nm and mean pore sizes around 5 nm.

Ionogels are solid oxide host networks confining at a meso-scale ionic liquids, and retaining their liquid nature. Ionogels were obtained by dissolving lanthanide(III) complexes in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C6mim][Tf2N], followed by confinement of the lanthanide-doped ionic liquid mixtures in the pores of a nano-porous silica network. [C6mim][Ln(tta)4], where tta is 2-thenoyltrifluoroacetonate and Ln=Nd, Sm, Eu, Ho, Er, Yb, and [choline]3[Tb(dpa)3], where dpa=pyridine-2,6-dicarboxylate (dipicolinate), were chosen as the lanthanide complexes. The ionogels are luminescent, ion-conductive inorganic-organic hybrid materials. Depending on the lanthanide(III) ion, emission in the visible or the near-infrared regions of the electromagnetic spectrum was observed. The work presented herein highlights that the confinement did not disturb the first coordination sphere of the lanthanide ions and also showed the excellent luminescence performance of the lanthanide tetrakis beta-diketonate complexes. The crystal structures of the complexes [C6mim][Yb(tta)4] and [choline]3[Tb(dpa)3] are reported.

(1)H MAS NMR and temperature-dependent relaxation time measurements were carried out for the first time on ionic liquids confined in monolithic silica matrices and enabled us to show that the ionic liquids' dynamics experienced only a very small slowing-down. The confinement preserved the ionic liquids' properties and, moreover, allowed liquid-like behaviour at temperatures below the crystallisation temperature of genuine ionic liquids. This study highlights the interest of the ionogel approach to all-solid state devices with genuine IL properties.

The acidity constants of the reduced and oxidized species of ferrocenylphosphonic acids FcPO3H2, FcCH2PO3H2 and fc(PO3H2)2 (Fc = (eta5-C5H5)Fe(eta5-C5H4), fc = (eta5-C5H4)Fe(eta5-C5H4)) in water have been evaluated by potentiometric, 31P NMR, and electrochemical methods. The oxidized forms are more acidic than the reduced ones. The interaction between the redox centre and the charged oxygen atoms of the phosphonate group is shown to be electrostatic. The maximum oxidation shift DeltaE between the protonated and unprotonated species increases with the number of charges of the substrate and decreases with the increase of the distance between the ferrocenyl centre and the oxygen atoms of the phosphonate group. The structure of FcPO3Na2.5H2O is determined. The compound crystallizes in the monoclinic system. It is lamellar with an inorganic layer formed by tetramers Na4O14, the ferrocenyl groups occupying the interlamellar space.

The confinement of ionic liquids within a porous silica matrix was performed by a one-step non-hydrolytic sol-gel route, leading to hybrid materials (called "ionogels") featuring both the mechanical and transparency properties of silica gels and the high ionic conductivity and thermal stability of ionic liquids.

Needs for ferrocene immobilization on robust host structures are considerable since derivative materials may find applications in medical areas, optical devices, or catalysis. Synthesis of phosphonate functionalized ferrocene allowed its subsequent inorganic polymerization with a zinc salt. The crystallographic structure of the compound obtained, Zn(HO(3)PFc)(2).2H(2)O, shows a unique two-dimensional ferrocene arrangement anchored on a one-dimensional Zn-O-P-O-Zn backbone. The ferrocene packing in the title compound is very similar to the packing found in molecular ferrocene. The electroactivity of Zn(HO(3)PFc)(2).2H(2)O is thoroughly studied. It shows a reversible surface oxidation of ferrocene. Mössbauer spectroscopy for the oxidized compound shows an isomer shift of IS(2b) = 0.432 mm x s(-1) and a quadrupolar splitting of QS(2b) = 0.205 mm x s(-1), which is consistent with a stable S = 1/2 ferrocenium state. The magnetic susceptibility study, Mössbauer spectroscopy, and galvanostatic titration show that only the ferrocene moieties present at the surface of the crystallites are reversibly oxidized. This observation is reinforced by a complex impedance study showing mainly resistive behavior and conductivity measurements indicating weak, thermally assisted, conductivity. The general properties of this compound demonstrate that phosphonato functionalization may be a useful approach for all fields concerned by immobilization of ferrocene.