Search

The demand for more efficient energy storage devices has led to the exponential growth of lithium-ion batteries. To overcome the limitations of these systems in terms of safety and to reduce environmental impact, solid-state technology emerges as a suitable approach. This work reports on a three-component solid polymer electrolyte system based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), the ionic liquid 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), and clinoptilolite zeolite (CPT). The influences of the preparation method and of the dopants on the electrolyte stability, ionic conductivity, and battery performance were studied. The developed electrolytes show an improved room temperature ionic conductivity (1.9 × 10–4 S cm–1), thermal stability (up to 300 °C), and mechanical stability. The corresponding batteries exhibit an outstanding room temperature performance of 160.3 mAh g–1 at a C/15-rate, with a capacity retention of 76% after 50 cycles. These results represent a step forward in a promising technology aiming the widespread implementation of solid-state batteries., FCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of Strategic Funding grants UID/CTM/50025/2021, UID/FIS/04650/2021, UID/EEA/04436/2021 and UID/QUI/0686/2021; and support from FEDER funds through the COMPETE 2020 Programme (projects PTDC/FISMAC/28157/2017 and POCI-01-0145-FEDER-007688). Grants SFRH/BD/140842/2018 (J.C.B.) and SFRH/BPD/121526/2016 (D.M.C) and contracts under the Stimulus of Scientific Employment, Individual Support CEECIND/00833/2017 (R.G.) and 2020.04028 CEECIND (C.M.C.) are acknowledged. Financial support from the Basque Government under the ELKARTEK program, Basque University System Research Groups, IT-1290-19 and the University of the Basque Country (GIU18/197). is also acknowledged

International audience

Electrochromic devices (ECDs) combining visible/near-infrared (NIR) transparent amorphous indium zinc oxide (a-IZO) external layers with innovative NIR-emitting electrolytes composed of red seaweed-derived kappa-carrageenan (kappa-Cg) polysaccharide, glycerol (Gly), and erbium triflate (ErTrif(3)center dot xH(2)O) are proposed as a valuable technological solution for the development of smart windows providing less heating demand, less glare and more indoors human comfort for the new generation of energy-efficient buildings. The electrolyte preparation is cheap, clean, and fast. The optimized sample including 50 wt% Gly/kappa-Cg and 40 wt% ErTrif(3)center dot xH(2)O/kappa-Cg exhibits the highest ionic conductivity (1.5 X 10(-4) S cm(-1) at 20 degrees C) and displays ultraviolet (UV)/blue and NIR emissions associated with the kappa-Cg-based host and the Er3+ ions (I-4(15/2) -> I-4(13/2)), respectively. The 5-layer configuration ECD tested demonstrated fast switching time (50 s), high electrochromic contrast (transmittance variations of 46/51% at 550/1000 nm), high optical density change (0.89/0.75 at 550/1000 nm), outstanding coloration efficiency (450th cycle = -15902/-13400 cm(2) C-1 and +3072/+2589 cm(2) C-1 at 550/1000 nm for coloration and bleaching, respectively), excellent electrochemical stability, and self-healing after mechanical damage. The ECD encompasses two voltage-operated modes: semibright warm (+3.0 V, transmittances of 52/61% at 550/1000 nm) and dark cold (-3.0 V, transmittances of 7/11% at 550/1000 nm)., This work was supported by FEDER, through COMPETE and Fundacao para a Ciencia e a Tecnologia (FCT) (FCOMP-01-0124-FEDER-037271, Pest-OE/QUI/UI0616/2014, and UID/CTM/50025/2019), project LUMECD (POCI-01-0145-FEDER-016884 and PTDC/CTM-NAN/0956/2014), project UniRCell (ref. SAICTPAC/0032/2015, POCI-01-0145-FEDER-016422), and by the Portuguese National NMR Network (RNRMN). S.C.N. acknowledges FCT for grants (Post -PhD Fellowships of UniRCell and LUMECD projects). R.F.P.P. acknowledges FCT for SFRH/BPD/87759/2012 grant. The authors thank CPKelco (U.S.A.) for providing the x-carrageenan sample.

The authors wish to make a change to their published paper [1]. In the original manuscript, there is a mistake in a sentence in Section 3.5, on page 10. Two words “anions and cations” were reverted by mistake. The corrected sentence is shown below: The strain developed as a response to the applied electrical field results from the diffusion of the ions and migration to the positive (anions) and negative (cations) electrode layers, and subsequent accumulation close to the electrodes. The authors apologize for any inconvenience caused, and the change does not affect the scientific results. The manuscript will be updated, and the original will remain online on the article webpage at https://www.mdpi.com/2073-4360/12/5/1187., (undefined)

A di-urethane cross-linked poly(oxyethylene)/silica hybrid matrix [di-urethanesil, d-Ut(600)], synthesized by the sol-gel process, was doped with lithium triflate (LiCF3SO3) and the 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) ionic liquid. The as-produced xerogel film is amorphous, transparent, flexible, homogeneous, hydrophilic, and has low nanoscale surface roughness. It exhibits an ionic conductivity of 3.64 x 10(-6) and 5.00 x 10(-4) S cm(-1) at 21 and 100 degrees C, respectively. This material was successfully tested as electrolyte in an electrochromic device (ECD) with the glass/ITO/a-WO3/d-Ut(600)(10)LiCF3SO3[Bmim]Cl/c-NiO/ITO/glass configuration, where a-WO3 and c-NiO stand for amorphous tungsten oxide and crystalline nickel oxide, respectively. The device demonstrated attractive electro-optical performance: fast response times (1-2 s for coloring and 50 s for bleaching), good optical memory [loss of transmittance (T) of only 41% after 3 months, at 555 nm], four mode modulation [bright mode (+3.0 V, T = 77% at 555 nm), semi-bright mode (-1.0 V, T = 60% at 555 nm), dark mode (-1.5 V, T = 38 % at 555 nm), and very dark mode (-2.0 V, T = 11% and -2.5 V, T = 7% at 555 nm)], excellent cycling stability denoting improvement with time, and high coloration efficiency [CEin = -6727 cm(2) C-1 (32th cycle) and CEout = +2794 cm(2) C-1 (480th cycle), at 555 nm]., The authors are grateful to Fundacao para a Ciencia e a Tecnologia (FCT) and when applicable by FEDER under the PT2020 Partnership Agreement for financial support under contracts PEst-OE/SAU/UI0709/2014, UID/Multi/00709/2013, UID/QUI/00686/2016, UID/QUI/00686/2018, UID/QUI/00686/2019, PEst-OE/QUI/UI0616/2016, FCOMP-01-0124-FEDER037271, UID/CTM/50011/2013, LUMECD project (POCI01-0145-FEDER-016884 and PTDC/CTM-NAN/0956/2014), UniRCell project (SAICTPAC/0032/2015 and POCI-01-0145FEDER-016422). RP and SN acknowledge FCT-MCTES for grants (SFRH/BPD/87759/2012 and LUMECD, respectively). RP thanks FCT-UM for the contracts in the scope of Decreto-Lei 57/2016 and 57/2017. MF acknowledges FCTUTAD for the contract in the scope of Decreto-Lei 57/2016 -Lei 57/2017. HG acknowledges projects POCI-010145-FEDER-030858 and PTDC/BTM-MAT/30858/2017 for financial support.

Novel electrolytes composed of chondroitin sulfate A (CSA) and citric acid (CA) have been prepared using a clean, safe, and fast route. These electrolytes exhibit different physical-chemical properties, depending on the amount of CA. For X > 82.3%, where X is the mass ratio, in %, of CA/(CA + CSA), whitish polycrystalline powders result. Lower amounts of CA leads to the production of translucent, amorphous films, sticky for X = 75.6 and 82.0, brittle for X < 43.6 and crack-free, self-standing for 43.6 < X < 75.6%. The results obtained provide evidence that, at low pH, strong hydrogen bonding interactions take place between the anionic sulfonic and carboxylic groups of CSA and CA. CA exerts a key role, acting as a cross-linker and proton source, while simultaneously influencing sample morphology. At room temperature the highest ionic conductivity is achieved at X = 60.8%. A significant enhancement of the ionic conductivity of this sample occurs with the increase of relative humidity (RH) (from 3.1 × 10−7 to 3.7 × 10−2 S cm−1 30% for RH = 30 and ~100%, respectively)., Support by Fundação para a Ciência e Tecnologia, I.P. (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, UID/QUI/ 00686/2013, UID/QUI/50006/2019 and UID/QUI/00686/2016. This work was funded by the R&D Project UniRCell-Unitised regenerative fuel cell for efficient renewable energy supply: from materials to device, with reference POCI-01-0145-FEDER-016422 and SAICTPAC/0032/ 2015, financed by the European Regional Development Fund (ERDF) through COMPETE 2020 – Operational Program for Competitiveness and Internationalization (POCI) and by the Foundation for Science and Technology (FCT) and CICECO-Aveiro Institute of Materials (UID/ CTM/50011/2019), financed by national funds through the FCT/MEC. Is also acknowledged, as well as funding under projects UID/CTM/ 50025/2013, Pest-OE/QUI/UI0616/2014, and LUMECD (PTDC/CTM/ NAN/0956/20149 and POCI-01-0145-FEDER-016884). F. M. Santos acknowledges a Post-PhD Fellow grant supported by Project UniRcell. P. C. Barbosa employment contract is funded by national funds (OE), through FCT – Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.R. F. P. Pereira Post-PhD fellow was funded by FCT (SFRH/BPD/87759/2012). S. C. Nunes was funded by FCT projects (Post-PhD Fellowships of UniRCell and LUMECD projects). H.M.R. Gonçalves was funded by NORTE-01-0145-FEDER-030858 and PTDC/ BTM-MAT/30858/2017.

New mesoporous silk fibroin (SF)/silica hybrids were processed via a one-pot soft and energy-efficient sol-gel chemistry and self-assembly from a silica precursor, an acidic or basic catalyst, and the ionic liquid 1-butyl-3-methylimidazolium chloride, acting as both solvent and mesoporosity-inducer. The as-prepared materials were obtained as slightly transparent-opaque, amorphous monoliths, easily transformed into powders, and stable up to ca. 300 degrees C. Structural data suggest the formation of a hexagonal mesostructure with low range order and apparent surface areas, pore volumes, and pore radii of 205-263 m(2) g(-1), 0.16-0.19 cm(3) g(-1), and 1.2-1.6 nm, respectively. In all samples, the dominating conformation of the SF chains is the beta-sheet. Cytotoxicity/bioactivity resazurin assays and fluorescence microscopy demonstrate the high viability of MC3T3 pre-osteoblasts to indirect (>= 99 +/- 9%) and direct (78 +/- 2 to 99 +/- 13%) contact with the SF/silica materials. Considering their properties and further improvements, these systems are promising candidates to be explored in bone tissue engineering. They also offer excellent prospects as electrolytes for solid-state electrochemical devices, in particular for fuel cells., This work was supported by Fundacao para a Ciencia e a Tecnologia (FCT)/Deutscher Akademischer Austauschdienst (DAAD) Transnational Cooperation Project no. 6818 "Ionic liquid-and ionic liquid crystal-assisted formation of hybrid biomaterials scaffolds". We further wish to thank the European Union, QREN, FEDER through "Programa Operacional Factores de Competitividade" (COMPETE), and CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. This work was also funded by project UniRCell (POCI-01-0145-FEDER-016422 and SAICTPAC/0032/2015) financed by the European Regional Development Fund (ERDF) through COMPETE 2020, POCI and FCT. We also thank FCT in the framework of Strategic Funding UID/QUI/00686/2013 and UID/QUI/00686/2016, and funding under project PEst-OE/QUI/UI0616/2014. R.F.P.P. acknowledges FCT for a grant (SFRH/BPD/87759/2012).

The synthesis, structure, and photocatalytic water splitting performance of two new titania (TiO 2 )/gold(Au)/Bombyx mori silk hybrid materials are reported. All materials are monoliths with diameters of up to ca. 4.5 cm. The materials are macroscopically homogeneous and porous with surface areas between 170 and 210 m 2/g. The diameter of the TiO 2 nanoparticles (NPs) – mainly anatase with a minor fraction of brookite – and the Au NPs are on the order of 5 and 7–18 nm, respectively. Addition of poly(ethylene oxide) to the reaction mixture enables pore size tuning, thus providing access to different materials with different photocatalytic activities. Water splitting experiments using a sunlight simulator and a Xe lamp show that the new hybrid materials are effective water splitting catalysts and produce up to 30 mmol of hydrogen per 24 h. Overall the article demonstrates that the combination of a renewable and robust scaffold such as B. mori silk with a photoactive material provides a promising approach to new monolithic photocatalysts that can easily be recycled and show great potential for application in lightweight devices for green fuel production., Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, 581

Polymer electrolytes (PEs) are of much attention as potential electrolytes of great technological relevance for solid-state electrochemistry, in particular for their possible practical application in devices such as batteries, supercapacitors, fuel cells, smart windows, sensors, and solar cells, among others. Generically, solid polymer electrolytes (SPEs) are mixtures of salts with basic polymers, such as poly(ethylene oxide) (PEO) or poly(ethylene imine) (PEI). However, there are also other polymers used as matrices for ionic conduction, like poly(vinyl alcohol) (PVA), poly(vinylidene fluoride) (PVDF), or natural macromolecules. A brief description of theoretical aspects of different PEs and past and recent trends in development of these materials are presented in this chapter. SPEs have many advantages including high energy density, no risk of leakage, no deleterious issues related to the presence of solvent, wide electrochemical stability window, simplified processability, and light weight. Some examples of prototypes of electrochromic device (ECD), batteries, supercapacitors, fuel cells, sensors, dye sensitized solar cells (DSSCs), and light emitting electrochemical cells are also presented and discussed in scope of this contribution., (undefined)

Poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE), poly(vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP) and poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) were evaluated for the development of ionic liquid (IL) - polymer composite bending actuators. The selected guest IL, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [Emim][TFSI], was incorporated into the different host polymer matrixes in concentrations ranging from 10 to 40wt%. The IL/polymer composites electrical properties strongly depend on the IL content. The largest bending response was found for the IL/PVDF-TrFE composites with a maximum bending value of 3.5mm using a frequency of 100mHzat an applied potential difference of 5.0 Vpp. Thus, PVDF-TrFE are attractive candidates for the development of high performance bending actuators., Work supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, UID/QUI/00686/2013 and UID/QUI/0686/2016. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013 and Grants SFRH/BD/90215/2012 (J.C.D.), SFRH/BPD/121526/2016 (D.M.C), SFRH/BPD/112547/2015 (C.M.C.), SFRH/BPD/90870/2012 (C.R.). Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including the FEDER financial support) and from the Basque Government Industry Department under the ELKARTEK and HAZITEK program and Grupos de Investigación, IT718-13, is also acknowledged., info:eu-repo/semantics/publishedVersion

The integration of photovoltaic (PV) elements in urban environments is gaining visibility due to the current interest in developing energetically self-sustainable buildings. Luminescent solar concentrators (LSCs) may be seen as a solution to convert urban elements, such as fa&ccedil, ades and windows, into energy-generation units for zero-energy buildings. Moreover, LSCs are able to reduce the mismatch between the AM1.5G spectrum and the PV cells absorption. In this work, we report optically active coatings for LSCs based on lanthanide ions (Ln3+ = Eu3+, Tb3+)-doped surface functionalized ionosilicas (ISs) embedded in poly(methyl methacrylate) (PMMA). These new visible-emitting films exhibit large Stokes-shift, enabling the production of transparent coatings with negligible self-absorption and large molar extinction coefficient and brightness values (~2 &times, 105 and ~104 M&minus, 1∙cm&minus, 1, respectively) analogous to that of orange/red-emitting organic dyes. LSCs showed great potential for efficient and environmentally resistant devices, with optical conversion efficiency values of ~0.27% and ~0.34%, respectively.

To address the challenges of the next generation of smart windows for energy-efficient buildings, new electrochromic devices (ECDs) are introduced. These include indium molybdenum oxide (IMO), a conducting oxide transparent in the near-infrared (NIR) region, and a NIR-emitting electrolyte. The novel electrolytes are based on a sol-gel-derived di-urethane cross-linked siloxane-based host structure, including short chains of poly (&epsilon, caprolactone) (PCL(530) (where 530 represents the average molecular weight in g mol&minus, 1). This hybrid framework was doped with a combination of either, lithium triflate (LiTrif) and erbium triflate (ErTrif3), or LiTrif and bisaquatris (thenoyltrifluoroacetonate) erbium (III) ([Er(tta)3(H2O)2]). The ECD@LiTrif-[Er(tta)3(H2O)2] device presents a typical Er3+ NIR emission around 1550 nm. The figures of merit of these devices are high cycling stability, good reversibility, and unusually high coloration efficiency (CE = &Delta, OD/&Delta, Q, where Q is the inserted/de-inserted charge density). CE values of &minus, 8824/+6569 cm2 C&minus, 1 and &minus, 8243/+5200 cm2 C&minus, 1 were achieved at 555 nm on the 400th cycle, for ECD@LiTrif-ErTrif3 and ECD@LiTrif-[Er(tta)3(H2O)2], respectively.

We introduce a bio-inspired strategy for the synthesis of green polymer electrolytes (PEs) which relies on the use of silk fibroin (SF). The two series of PEs prepared, doped with lithium bis(trifluoromethanesulfonyl)imide (SF@LiTFSI) or lithium tetrafluoroborate (SF@LiBF4) and incorporating glycerol, exhibited outstanding filmogenic properties, very high transparency and suitable adhesion to glass substrates. Despite their poor ionic conductivity, the SF-based films (SF@) were employed in the construction of glass/ITO/WO3/SF@/CeO2-TiO2/ITO/glass electrochromic devices displaying an optical modulation up to 5.5 % at 633 nm, switching speed of ca. 15 s, stability up to 5160 cycles, and coloration efficiency up to −53.1 m2 C−1 . This work, in which we provide the proof-of-concept, paves the way for new design approaches for silk-based materials, enlarging the range of applications of SF to the energy field., This work was supported by Fundação para a Ciência e a Tecnologia (FCT) and Feder (contracts PTDC/CTMBPC/112774/2009, PEst-OE/QUI/UI0616/2014 and PEstC/QUI/UI0686/2013) and COST Action MP1202 “Rational design of hybrid organic-inorganic interfaces”. R.F.P.P. acknowledges FCT for a grant (SFRH/BPD/87759/2012). M.M.S. acknowledges Fundação Luso-Americana (FLAD) and CNPq (PVE grant 406617/2013-9), for a mobility grant., info:eu-repo/semantics/publishedVersion

Non-Newtonian nanofluids present outstanding features in terms of energy transfer and conductivity with high application in numerous areas. In this work, non-Newtonian nanofluids based on carbon dots (Cdots) functionalized with ionic liquids (ILs) are developed. The nanofluids are produced using a simple, single-step method where the raw materials for the Cdots synthesis are glucose and waste biomass (chitin from crab shells). The use of ILs as both reaction media and functionalization molecules allows for the development of a new class of nanofluids, where the ILs on the Cdots surface represent the base-fluid. Here, the well-known benign IL 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and a novel home-made IL (1-tosylate-3-methyl-imidazolium triflate) [Tmi][Trif] are used. The nanofluids obtained from both substrates show, apart from high conductivity and viscosity, light absorption, and good wettability, an appealing thermal sensitivity behavior. This thermal sensitivity is preserved even when applied as thin films on glass slides and can be boosted using the surface plasmon resonance effect. The results reported demonstrate that the new Cdots/IL-based nanofluids constitute a versatile and cost-effective route for achieving high-performance thermosensitive non-Newtonian sustainable nanofluids with tremendous potential for the energy coatings sector and heat transfer film systems., This research was funded by National Funds by Foundation for Science and Technology (FCT) and by FEDER funds through POCI-COMPETE 2020-Operational Programme Competitiveness and Internationalization in Axis I—Strengthening Research, Technological Development and Innovation (UID/QUI/00616/2013, UID/QUI/50006/2019, UID/ Multi/00709/2013, UID/QUI/00313/2019, UID/CTM/50025, POCI-01- 0145-FEDER-007491, POCI-01-0145-FEDER-007688, UID/CTM/50025, POCI-01-0145-FEDER-016884, PTDC/CTM-NAN/0956/2014, SAICT/ PAC/0032/2015, POCI-01-0145-FEDER-016422, and NORTE-01-0145- FEDER-030858). R.F.P.P. acknowledges FCT-MCTES for SFRH/ BPD/87759/2012 grant. E. Pereira (FCUP, Porto) is acknowledged for her assistance

This work reports on the development of bending actuators based on poly(l-lactic acid) (PLLA)/ionic liquid (IL) blends, through the incorporation of 40% wt. of the 1-ethyl-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) IL. The films, obtained by solvent casting at room temperature and 50 &deg, C, were subjected to several post-thermal treatments at 70, 90, 120 and 140 &deg, C, in order to modify the crystallinity of the films. The influence of the drying temperature and of [Emim][TFSI] blending on the morphological, structural, mechanical and electrical properties of the composite materials were studied. The IL induced the formation of a porous surface independently of the processing conditions. Moreover, the [Emim][TFSI] dopant and the post-thermal treatments at 70 &deg, C promoted an increase of the degree of crystallinity of the samples. No significant changes were observed in the degree of crystallinity and Young Modulus for samples with thermal treatment between 70 and 140 &deg, C. The viability of the developed high ionic conductive blends for applications as soft actuators was evaluated. A maximum displacement of 1.7 mm was achieved with the PLLA/[Emim][TFSI] composite prepared at 50 &deg, C and thermally treated at 140 &deg, C, for an applied voltage of 10 Vpp, at a frequency of 100 mHz. This work highlights interesting avenues for the use of PLLA in the field of actuators.

The development of materials that can help overcome the current limitations in energy storage and consumption is a pressing need. Recently, we developed non-Newtonian nanofluids based on non-toxic, carbon nanoparticles (NPs), carbon dots (Cdots) functionalized with ionic liquids. Here, we wanted to prove that these new nanofluids are, not only interesting as possible electrolytes, but also as new organic/inorganic hybrid separators. As such, we developed an entrapment method using poly(vinyl alcohol) (PVA). Indeed, the highly conductive Cdots were successfully retained inside the membrane even upon the application of several wetting/drying cycles. Moreover, the morphological characteristics did not change upon wetting/drying cycles and remained constant for more than four months. These nanofluids could be an interesting approach to tackle some of the current problems in the fields of solid-state batteries, and energy storage, among others.

Battery separators based on silk fibroin (SF) have been prepared aiming at improving the environmental issues of lithium-ioh, batteries. SF materials with three different morphologies were produced: membrane films (SF-F), sponges prepared by lyophilization (SF-L) and: electrospuri membranes (SF-E). The latter Materials presented a suitable porons,three-dimensional microstructure and were soaked with a I M LiPF6 electrolyte: The ionic conductivities for SF-L and SF-E were 1.00 and 0.32 mS cm(-1) at 20 degrees C, respectively. A correlation between the fraction "of beta-sheet conformations and the ionic conductivity was observed. The electrochemical performance of the SF-based materials was evaluated by incorporating them in cathodic half-cells with C-LiFePO4. The discharge capacities of SF-L and SF-E were 126 and 108 mA h g(-1), respectively, at the C/Iirate and 99 and 54 mA h g(-1), respectively, at the 2C-rate. Furthermore, the capacity retention and capacity fade of the SF-L membrane after 50 cycles at the 2C-rate were 72 and 5%, respectively. These electrochemical results show that a high percentage of beta-sheet conformations, were of prime importance to guarantee excellent cycling performance. This work demonstrates that SP-based membranes are appropriate separators for the production of environmentally friendlier lithium-ion batteries., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, ULD/QUI/00686/2013 and ULD/QUI/00686/2016. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013, PEst-OE/QUI/UI0616/2014, and LUMECD (POCI-01-0145-FEDER-016884 and PTDC/CTM-NAN/0956/2014), grants SFRH/BPD/87759/2012 (R.F.P.P.), and SFRH/BPD/112547/2015 (C.M.C.). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK program., info:eu-repo/semantics/publishedVersion

Amine-functionalized bridged silsesquioxanes (BSs) were synthesized from bis[(3-trimethoxysilyl)propyl] amine via a solvent-mediated route. BS-1 and BS-2 were obtained at neutral pH with sub- and stoichiometric amounts of water, respectively, and high tetrahydrofuran content. BS-3 was prepared with hyperstoichiometric water concentration, high tetrahydrofuran content, and hydrochloric acid. BS-4 was synthesized with hyperstoichiometric water concentration, high ethanol content, and sodium hydroxide. BS-1 and BS-2 were produced as transparent films, whereas BS-3 and BS-4 formed white powders. Face-to-face stacking of flat or folded lamellae yielded quasi-hydrophobic platelets with emission quantum yields of 0.05 ± 0.01 (BS-1 and BS-2) or superhydrophilic onion-like nanoparticles with exciting emission quantum yields of 0.38 ± 0.03 (BS-3) and 0.33 ± 0.04 (BS-4), respectively. The latter two values are the largest ever reported for amine-functionalized siloxane-based hybrids lacking aromatic groups. Fast Grotthus proton hopping between = [Formula: see text]/ = NH groups (BS-3) and = N-/ = NH groups (BS-4), promoted by H+ and OH- ions, respectively, and aided by short amine-amine contacts provided by the onion-like morphology, account for this unique optical behavior., This work was supported by Fundacao para a Ciencia e a Tecnologia (FCT)/MEC and FEDER (contracts UID/QUI/00616/2013, POCI-01-0145-FEDER-007491, and UID/Multi/00709/2013) and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement, project UniRCell (Ref. SAICTPAC/0032/2015, POCI-01-0145-FEDER-016422), and project LUMECD (Ref. PTDC/CTM/NAN/0956/20149 and POCI-01-0145-FEDER-016884). RP and MC acknowledge FCT for grants SFRH/BPD/87759/2012 and SFRH/BD/118466/2016, respectively. SN also acknowledges FCT for grants SFRH/BPD/63152/2009 and Post-PhD Fellowship of LUMECD project. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT-Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement.

In the quest for solutions to enhance the safety and sustainability of energy storage devices, Bombyx mori silkworm cocoons are proposed as separators for lithium (Li)‐ion batteries obtained literally from nature, and employed directly in a device. The suitability of the cocoons is evaluated in Li‐ion batteries using two different electrolytes: a mixture of lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC), and dimethyl carbonate (DMC), and the ionic liquid (IL) 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim]TFSI). Li/C–LiFePO4 half cells comprising the EC–DMC–LiPF6 electrolyte present excellent cycling performance, with a discharge capacity up to 86 mAh g−1 and a capacity retention up to 81% after 50 cycles at C rate. Values of 66 mAh g−1 at C/5 and 85% result with [Emim]TFSI, respectively. Separator/electrolyte interactions during battery cycling lead to a decrease of the degree of crystallinity of the cocoon silk fibers, and, in the presence of EC–DMC–LiPF6, to a concomitant increase of the concentration of free PF6− ions. The self‐extinguishing ability of silkworm cocoons represents an additional benefit to batteries, providing fire risk reduction or even suppression. This bio‐inspired work paves the way toward the fabrication of environmentally friendlier separators for next‐generation sustainable and safer Li‐ion batteries., R.F.P.P. and R.G. contributed equally to this work. This work was supported by National funds by Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, UID/QUI/00686/2013 and UID/QUI/00686/2016. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects POCI-01-0145-FEDER-028157 PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013, PEst-OE/QUI/UI0616/2014, and grants SFRH/BPD/87759/2012 (R.F.P.P.), SFRH/BPD/112547/2015 (C.M.C.), and UniRCell project (SAICTPAC/0032/2015 and POCI-01-0145-FEDER-016422). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK and HAZITEK programs. The authors thank F. A. Almeida Paz (CICECO-Instituto de Materiais de Aveiro, Aveiro, Portugal) for recording the XRD patterns., info:eu-repo/semantics/publishedVersion

Ionic liquids (ILs) have attracted tremendous interest in the last decades. This is due to their high chemical variability and their interesting and useful chemical, physical, and biological properties. The current chapter provides an overview on the use and the potential of ILs for biopolymer dissolution and processing, for chemical modification of biopolymers in ILs, and on the use of ILs for the fabrication of biocompatible materials and composites from renewable resources.

Luminescent solar concentrators (LSCs) appear as candidates to enhance the performance of photovoltaic (PV) cells and contribute to reduce the size of PV systems, decreasing, therefore, the amount of material needed and thus the cost associated with energy conversion. One way to maximize the device performance is to explore near-infrared (NIR)-emitting centers, resonant with the maximum optical response of the most common Si-based PV cells. Nevertheless, very few examples in the literature demonstrate the feasibility of fabricating LSCs emitting in the NIR region. In this work, NIR-emitting LSCs are reported using silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (SiNc or NIR775) immobilized in an organic-inorganic tri-ureasil matrix (t-U(5000)). The photophysical properties of the SiNc dye incorporated into the tri-ureasil host closely resembled those of SiNc in tetrahydrofuran solution (an absolute emission quantum yield of ∼0.17 and a fluorescence lifetime of ∼3.6 ns). The LSC coupled to a Si-based PV device revealed an optical conversion efficiency of ∼1.5%, which is among the largest values known in the literature for NIR-emitting LSCs. The LSCs were posteriorly coupled to a Si-based commercial PV cell, and the synergy between the t-U(5000) and SiNc molecules enabled an effective increase in the external quantum efficiency of PV cells, exceeding 20% in the SiNc absorption region.

Green electrolytes composed of kappa-carrageenan (κ-Cg), 1-butyl-3-methyl-1H-imidazolium chloride ([Bmim]Cl) ionic liquid, and glycerol (Gly) are prepared in aqueous solution using a simple, clean, fast and low-cost procedure. A flexible membrane incorporating 50% wt [Bmim]Cl and 50% wt Gly with respect to κ-Cg exhibits the highest ionic conductivity values (8.47 ×10−4/2.45 × 10−3 S cm−1 at 20/66 °C, under anhydrous conditions, and 5.49 × 10−2/0.186 S cm−1 at 30/60 °C, at a relative humidity of 98%). Tests of room temperature air/hydrogen fuel cells incorporating κ-Cg, κ-Cg/Gly, and κ-Cg/Gly/[Bmim]Cl membranes demonstrate that these predominantly protonic conductors electrolytes are particularly well suited for the design and fabrication of eco-friendly electrochemical devices whose operation does not require the flow of gases and does not lead to water formation. These new materials have excellent application prospects in high performance (flexible) energy storage devices (supercapacitors and batteries) and electrochromic devices., This work was supported by National Funds by FCT—Foundation for Science and Technology—and by FEDER funds through the POCI— COMPETE 2020—Operational Programme Competitiveness and Internationalisation in Axis I – Strengthening research, technological development and innovation (POCI-01-0145-FEDER-007491, FCOMP01-0124-FEDER-037271, Pest-OE/QUI/UI0616/2014, Pest-C/QUI/UI0686/2013, PEst-OE/SAU/UI0709/2014, UID/CTM/50011/2013,UID/ Multi/00709/2013 and LUMECD project (POCI-01-0145- FEDER-016884 and PTDC/CTM-NAN/0956/2014)), project UniRCell (Ref. SAICTPAC/0032/2015, POCI-01-0145-FEDER-016422), by COST Action MP1202880 “Rational design of hybrid organic–inorganic interfaces” and by the Portuguese National NMR Network (RNRMN). S.C.N. acknowledge FCT for grants, Post-Ph.D. Fellowship of LUMECD project and SFRH/BPD/63152/2009. R.F.P.P., N.S., and F.M.F. acknowledge FCT for grants (SFRH/BPD/87759/2012, SFRH/ BD/89670/2012, and IF/01174/2013, respectively)., info:eu-repo/semantics/publishedVersion

International audience; The copper-catalyzed alkyne azide cycloaddition (CuAAC) reaction was combined with sol-gel reactions for the production of bridged silsesquioxanes (BSs) in which hexyl and icosanyl chains are pendant and anchored on a single position to a triazole ring. The influence of the alkyl chain length on the structure of the BSs, represented by the notation Cn/ siloxane (where n = 6 and 20), was examined. The C20/siloxane hybrid is a hydrophobic material that exhibits a hierarchically structured lamellar bilayer organization, a texturecomposed of microplates of nanometer thickness, and a reversible time-independent order/disorder phase transition (onset at 60 °C). The driving forces for self-assembly are van der Waals interactions between the icosanyl chains and π-π interactions between the triazole rings. In the essentially amorphous C6/siloxane hybrid, the latter contribution promotesthe genesis of a pre-lamellar phase similar to that found in C20/siloxane.

The design of new advanced materials and technologies is essential for the development of smart windows for the next generation of energy‐efficient buildings. Here, it is demonstrated that the functionalization of glucose‐derived carbon dots with 1‐butyl‐3‐methylimidazolium chloride results in a self‐standing, water‐soluble, viscous, reusable nanofluid with self‐improving conductivity, thermotropy around 30–40 °C, and ultraviolet blocking ability. Its synthesis is straightforward, clean, fast, and cheap. At 36 °C (hot summer day), a sun‐actuated thermotropic (TT) device incorporating a 95% w/w nanofluid aqueous solution exhibits a transmittance variation (ΔT ) of 9% at 550/1000 nm, which is amplified to 47/31% via the surface plasmon resonance effect. An integrated self‐healing system enabling independent sun‐actuated TT and voltage‐actuated electrochromic (EC) operation is also produced. The low‐energy EC device offers bright hot and dark cold modes (ΔT = 68/64%), excellent cycling stability, unprecedented coloration efficiency values (−1.73 × 106/−1.67 × 106 cm2 C−1 (coloring) and +1.12 × 107/+1.08 × 107 cm2 C−1 (bleaching) at ±2.5 V), and impressive memory effect. The disruptive design and sustainable synthesis of the new nanofluid proposed here will foster the agile development of novel products with improved ecological footprint., This research was funded by the National Funds by Foundation for Science and Technology (FCT) and by the FEDER funds through POCI-COMPETE 2020-Operational Programme Competitiveness and Internationalization in Axis I: Strengthening research, technological development and innovation (UID/QUI/00616/2013, UID/QUI/50006/2019, UID/Multi/00709/2013, UID/QUI/00313/2019, UID/CTM/50025, POCI-01-0145-FEDER-007491, POCI-01-0145-FEDER-007688, UID/CTM/50025, POCI-01-0145-FEDER-016884, PTDC/CTM-NAN/0956/2014, SAICT/PAC/0032/2015, POCI-01-0145-FEDER-016422, and NORTE-01-0145-FEDER-030858). R.F.P.P. acknowledges FCT-MCTES for SFRH/BPD/87759/2012 grant. R. Rego and M. Fernandes (UTAD, Vila Real) and E. Pereira (FCUP, Porto) are acknowledged for their assistance.

The protic ionic liquid (PIL) N-butylimidazolium trifluoromethanesulfonate ([BIm][TfO]) was obtained for the first time and incorporated into a sol-gel derived di-ureasil matrix with a concentration of X = 5, 10 and 30 %, where X is the ratio of the mass of PIL per mass of poly(oxyethylene) (POE). Four years after their synthesis, the resulting quasi-anhydrous electrolytes remained amorphous, homogeneous, flexible and thermally stable below 200 ºC. SEM/EDS data revealed the presence of the PIL at the surface of the xerogels with X > 5 %, demonstrating that this type of morphological characterization is mandatory to avoid misleading ionic conductivity values. The highest ionic conductivity was produced in the washed sample with X = 30 % (3.5 x10-5 and 2.1x10-3 S cm-1 at 25 and 170 ºC, respectively). The present family of electrolytes yielded higher conductivities than the N-ethylimidazolium trifluoromethanesulfonate-based analogues introduced earlier by our group and may be thus considered as promising candidates for applications in fuel cells., Fundação para a Ciência e a Tecnologia (FCT) and when applicable by FEDER under the PT2020 Partnership Agreement for financial support (contracts PTDC/CTM - BPC/112774/2009, UID/Multi/00709/2013, PEst - C/QUI/ UI0686/2013, PEst - OE/QUI/UI0616/2014 and FCT UID/CTM/50011/2013 ) and COST Action MP1202

Hollow multilayered capsules have shown massive potential for being used in the biomedical and biotechnology fields, in applications such as cellular internalization, intracellular trafficking, drug delivery, or tissue engineering. In particular, hollow microcapsules, developed by resorting to porous calcium carbonate sacrificial templates, natural-origin building blocks and the prominent Layer-by-Layer (LbL) technology, have attracted increasing attention owing to their key features. However, these microcapsules revealed a great tendency to aggregate, which represents a major hurdle when aiming for cellular internalization and intracellular therapeutics delivery. Herein, we report the preparation of well-dispersed polysaccharide-based hollow multilayered microcapsules by combining the LbL technique with an optimized purification process. Cationic chitosan (CHT) and anionic alginate (ALG) were chosen as the marine origin polysaccharides due to their biocompatibility and structural similarity to the extracellular matrices of living tissues. Moreover, the inexpensive and highly versatile LbL technology was used to fabricate core-shell microparticles and hollow multilayered microcapsules, with precise control over their composition and physicochemical properties, by repeating the alternate deposition of both materials. The microcapsules' synthesis procedure was optimized to extensively reduce their natural aggregation tendency, as shown by the morphological analysis monitored by advanced microscopy techniques. The well-dispersed microcapsules showed an enhanced uptake by fibroblasts, opening new perspectives for cellular internalization. published

New polymer electrolytes (PEs) based on chitosan and three ionic liquid (IL) families ([C2mim][CnSO3], [C2mim][CnSO4] and [C2mim][diCnPO4]) were synthesized by the solvent casting method. The effect of the length of the alkyl chain of the IL anion on the thermal, morphological and electrochemical properties of the PEs was studied. The solid polymer electrolytes (SPE) membranes were analyzed by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), polarized optical microscopy (POM), atomic force microscopy (AFM), complex impedance spectroscopy (ionic conductivity) and cyclic voltammetry (CV). The obtained results evidenced an influence of the alkyl chain length of the IL anion on the temperature of degradation, birefringence, surface roughness and ionic conductivity of the membranes. The DSC, XRD and CV results showed independency from the length of the IL-anion-alkyl chain. The PEs displayed an predominantly amorphous morphology, a minimum temperature of degradation of 135 °C, a room temperature (T = 25 °C) ionic conductivity of 7.78 × 10−4 S cm−1 and a wide electrochemical window of ∼ 4.0 V., This work was supported by FEDER through the COMPETE Program and by Fundação para a Ciência e a Tecnologia (FCT) in the framework of the Strategic Projects PEST-C/QUI/UI0686/2013, PEst-OE/SAU/UI0709/2014 and UID/Multi/00709/2013, UID/Multi/04551/2013, projects PTDC/QUI/117340/2010 and COST Action MP1202 “Rational design of hybrids organic inorganic interfaces”, grants SRFH/BD/90366/2012 (R.L.) and SFRH/BPD/63152/2009 (S.C. Nunes) and FCT Investigator contract (J.M.S.S.E.). The authors are also indebted to CNPq, FAPESP and CAPES for the financial support given to this research. M.M. Silva acknowledges Fundação Luso- Americana (FLAD) and CNPq (PVE grant 406617/2013-9), for the mobility grant provided by these institutions.

Hybrid organic/inorganic networks doped with europium triflate, Eu(CF 3 SO 3 ) 3 , have been prepared by the sol-gel method and characterized by conductivity and thermal analysis techniques. The electrolyte films produced were obtained as transparent, amorphous monoliths with encouraging optical characteristics and moderate bulk conductivities.

A lamellar bilayer hierarchically structured amide cross-linked alkyl/siloxane hybrid matrix (mono-amidosil, m-A(14)) was doped with a wide concentration range of potassium triflate (KCF3SO3), magnesium triflate (Mg(CF3SO3)2), and europium triflate (Eu(CF3SO3)3). In the K(+)-, Mg(2+)-, and Eu(3+)-based samples with n ≥ 5, 20, and 60 (where n is the molar ratio of amide C═O groups per cation), respectively, the original lamellar structure of m-A(14) coexists with a new lamellar phase with lower interlamellar distance. The texture of the mono-amidosils doped with K(+), Mg(2+), and Eu(3+) ions mimics cabbage leaves, foliated schist, and sea sponges, respectively. In the three series of materials, the cations bond to the oxygen atoms of the amide carbonyl groups. The amide-amide hydrogen-bonded array of m-A(14) is less perturbed by the inclusion of KCF3SO3 and Mg(CF3SO3)2 than by the incorporation of Eu(CF3SO3)3. The degree of ionic association is low for n ≥ 20. The cations coordinate to the oxygen atoms of the triflate ions, forming contact ion pairs at higher salt content. In the Mg(CF3SO3)2- and Eu(CF3SO3)3-containing materials with n = 5 and 10, respectively, crystalline salt is formed. The structural changes undergone by the alkyl chains of selected mono-amidosils in a heating/cooling cycle are reversible, are time-independent, and exhibit two distinct hysteresis domains, one associated with the order/disorder phase transition of the original lamellar bilayer structure of m-A(14) and the second one associated with the order/disorder phase transition of the new lamellar bilayer structure formed in the presence of the salts.

13 pages; International audience; A new family of lamellar bilayer hierarchically structured mono-urethane cross-linked alkyl/siloxanes designated as mono-alkyl-urethanesils and represented by the notation m-Ut(CY)-ac, with Y = 14, 16 and 22 (where Y is the number of carbon atoms of the pendant polymer chains and ac is acid catalyzed) was prepared by the sol-gel process and self-assembly routes. The compounds were obtained as solid powders and are thermally stable up to 250 C. The alkyl chains adopt essentially all-trans conformations and are interdigitated. The degree of interpenetration depends non-linearly on the chain length. The intrincate morphology of the samples mimicks cabbage leaves or the desert rose. The present system allowed us to conclude that the nature of the cross-link exerts a key role on the properties of this sort of silsesquioxanes. The hydrogen bonded array in the monoalkyl- urethanesils is considerably weaker than that formed in the analogue mono-amidosil m-A(14) incorporating alkyl chains with 15 carbon atoms. The order/disorder phase transition temperatures of the mono-alkyl-urethanesils with Y = 14 and 16 are lower than that of m-A(14), making the former samples mechanically more resistant to consecutive heating/cooling cycles. The frequency of conformationalsensitive infrared modes of m-Ut(C16)-ac exhibit hysteresis behaviour during cooling after undergoing the order/disorder phase transition, but, unlike m-A(14), the latter transition, although reversible, is apparently time-independent. The hybrids display an efficient emission at room temperature in the blue-green spectral region with a maximum emission quantum yield value of 0.11 ± 0.01 (excited at 350-380 nm), which is of the same order of magnitude of that reported for m-A(14).

A new family of biodegradable polymer/bioactive glass (BG) composite materials has emerged based on the availability of nano-sized bioactive particles. Such novel biocomposites can have enhanced performance, in terms of mechanical properties and bioactivity, and they can be designed to be used in bone regeneration approaches. In this work, membranes of chitosan (CTS) and chitosan with bioactive glass (BG) both micron and nano sized particles (CTS/μBG, CTS/nBG, respectively) were prepared by solvent casting. Microstructural and mechanical properties were evaluated in order to compare the effects of the incorporation of micro (μBG) and nano (nBG) particles in the chitosan matrix. In vitro bioactivity tests were performed to characterize the apatite layer that is formed on the surface of the material after being immersed in simulated body fluid (SBF). The biomineralization process on the biomaterials was also followed using non-conventional dynamic mechanical analysis (DMA), both online and offline. In such DMA experiments, the change in the storage modulus, E′, and the loss factor, tan δ, were measured as a function of the immersion time in SBF. The results demonstrated that CTS/nBG membranes possess enhanced mechanical properties and higher bioactivity in comparison with the CTS/μBG membranes. Such results suggest the potential of nBG for the development of bioactive composites for bone regeneration applications., This work was financially supported by Foundation for Science and Technology (FCT) by the projects PTDC/QUI/69263/2006, PTDC/CTM-BPC/112774/2009 and, through the scholarship SFRH/BD/64601/2009 granted to Sofia G. Caridade. The authors acknowledge Dr D. Mohn and Prof. W. Stark (Em Zurich) for providing the nBG particles used.

The present work is focused on gelatin-based electrolytes doped with a range of concentration of zinc triflate (Zn(CF3SO3)2). The transparent-thin-film samples have been represented by the notation GelatinnZn(CF3SO3)2, where n represents the zinc triflate salt concentration in the electrolyte membranes from 0.00 wt% to 10.93 wt% . The samples have been characterized by conductivity measurements, thermal analysis, cyclic voltammetry, X-ray diffraction (XRD), polarized optical microscopy (POM) and scanning electron microscopy (SEM). The gelatin-based electrolytes were also tested as ionic conductors in electrochromic devices with the glass/ITO/WO3/gelatin-based electrolyte/CeO2-TiO2/ITO/glass configuration.

In the present work Fourier Transform infrared and Raman spectroscopy were used to characterize the cation/polymer, cation/cross-link, cation/anion and hydrogen bonding interactions in hybrid electrolytes composed of lithium tetrafluoroborate (LiBF4) and di-urea cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks (di-ureasils) designated as d-(2000) and d-U(600) and incorporating polyether chains with ca. 40.5 and 8.5 oxyethylene repeat units, respectively. Samples with ∞ > n ≥ 2.5 (where n, composition, is the molar ratio of CH2CH2O units per Li+ ion) were analyzed. In both di-ureasil systems over the whole range of salt content examined the Li+ ions bond to the ether oxygen atoms of amorphous POE chains and to BF4- ions forming ion contact pairs. Spectroscopic evidences and SEM images confirm the presence of a crystalline POE/LiBF4 complex of unknown stoichiometry at n < 20 and 25, respectively. Ionic association is particularly important in the case of the d-U(600)-based materials, as a result of the presence of strong hydrogen-bonded aggregates that prevent the establishment of Li+/urea carbonyl oxygen atom interactions., Fundação para a Ciência e a Tecnologia (FCT)

International audience; The final morphology of the lamellar silsesquioxane produced from the (EtO)3Si(CH2)3NHC(¼O)NH(CH2)12NHC(¼O)NH(CH2)3Si(OEt)3 (P12) precursor using an acidcatalyst and a large excess of water was changed from rigid platelets (L12) to micro-objects that resemble sea sponges (L12D) upon simple mixing with dimethylsulfoxide (dmso). The microstructural modifications observed were ascertained by several techniques. A mechanism for the morphology tuning based on the polarity of the solvent mixture is proposed.

Diurea cross-linked bridged silsesquioxanes (BSs) C(10)C(11)C(10) derived from organosilane precursors, including decylene chains as side spacers and alkylene chains with variable length as central spacers (EtO)(3)Si- (CH(2))(10)-Y(CH(2))(n)-Y-(CH(2))(10)-Si(OEt)(3) (n = 7, 9-12; Y = urea group and Et = ethyl), have been synthesized through the combination of self-directed assembly and an acid-catalyzed sol gel route involving the addition of dimethylsulfoxide (DMSO) and a large excess of water. This new family of hybrids has enabled us to conclude that the length of the side spacers plays a unique role in the structuring of alkylene-based BSs, although their morphology remains unaffected. All the samples adopt a lamellar structure. While the alkylene chains are totally disordered in the case of the C(10)C(7)C(10) sample, a variable proportion of all-trans and gauche conformers exists in the materials with longer central spacers. The highest degree of structuring occurs for n = 9. The inclusion of decylene instead of propylene chains as side spacers leads to the formation of a stronger hydrogen-bonded urea-urea array as evidenced by two dimensional correlation Fourier transform infrared spectroscopic analysis. The emission spectra and emission quantum yields of the C(10)C(n)C(10) Cm materials are similar to those reported for diurea cross-linked alkylene-based BSs incorporating propylene chains as side spacers and prepared under different experimental conditions. The emission of the C(10)C(n)C(10) hybrids is ascribed to the overlap of two distinct components that occur within the urea cross-linkages and within the siliceous nanodomains. Time-resolved photoluminescence spectroscopy has provided evidence that the average distance between the siliceous domains and the urea cross-links is similar in the C(10)C(n)C(10) BSs and in oxyethylene-based hybrid analogues incorporating propylene chains as side spacers (diureasils), an indication that the longer side chains in the former materials adopt gauche conformations. It has also allowed us to demonstrate for the first time that the emission features of the urea-related component of the emission of alkylene-based BSs depend critically on the length of the side spacers.

International audience; Urea-based bis-silylated bipyridine (bpy) organic–inorganic hybrids incorporating different lanthanide (Ln3+) ions (Eu3+, Gd3+, Tb3+ or Eu3+/Tb3+) were obtained by the sol–gel process. The structure and the emission characteristics of the hybrids were ascertained using X-ray diffraction, nuclear magnetic resonance, Fourier transform infrared spectroscopy, photoluminescence, and quantum yield measurements. The hybrids feature both the emission of the host and the Eu 3+ and/or Tb3+ transitions allowing a fine-tuning of the color from the blue to the red, orange, or green spectral regions. Bpy-to-Ln3+ and Tb3+-to-Eu3+ energy transfer mechanisms are demonstrated and the hybrids present slightly distinct Ln3+ coordination spheres due to the different bpy/Ln3+ ratios.

International audience; The bridged silsesquioxane precursor (EtO)3Si(CH2)3NH(C=O)NH-(CH2)12-NH(C=O)NH-(CH2)3 Si(OEt)3, combining polymerizable silylated groups, urea functionalities, and alkyl chains, undergoes fluoride (F-)-catalyzed sol-gel reactions in the presence or absence of EuCl3 . 6H2O. Supramolecular self-assembly of the growing structure relies primarily on the establishment of strong and ordered hydrogen bonding interactions. In the case of the Eu3+-containing hybrids the lanthanide ions play a totally unparallel dual-role acting simultaneously as structure directing agents and structural probes to sense locally morphological alterations. In the early stages of the synthesis, while a fraction of the Eu3+ ions promotes the formation of a unidirectional urea-urea hydrogenbonded array, the remaining ions coordinate to silanol (Si-OH) groups inhibiting the growth of the siloxane network and yielding small anisotropic flakes (∼200 nm long). These are subsequently assembled on the micrometer scale in a brick-like tile-to-tile arrangement that ends up with the formation of fibers or twisted bundles (3.0-4.0 μm long and 0.5-1.0 μm wide). At higher Eu3+ concentrations, Eu3+-based ionic interfiber cross-links hinder the solvent flow and force adjacent fibers to adopt a bow-tie form (3.0-4.0 μm long and 3.0 μm wide at the tips). The hybrids are room temperature multiwavelength emitters because of the convolution of the hybrids' intrinsic emission and the Eu3+ intra-4f6 transitions. The photoluminescence features (5D0_7F0 energy, 5D0 quantum efficiency, number of coordinated water molecules, and experimental intensity parameters) as a function of the Eu3+ content and acidic- and F--catalyzed conditions used in the synthesis are compared to address the effect of the morphology in the photoluminescence features of the hybrid materials.

Variable chain length di-urethane cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks were prepared by application of a sol-gel strategy. These materials, designated as di-urethanesils (represented as d-Ut(Y’), where Y’ indicates the average molecular weight of the polymer segment), were doped with lithium triflate (LiCF3SO3). The two host hybrid matrices used, d-Ut(300) and d-Ut(600), incorporate POE chains with approximately 6 and 13 (OCH2CH2) repeat units, respectively. All the samples studied, with compositions ∞ > n ≥ 1 (where n is the molar ratio of (OCH2CH2) repeat units per Li+),, are entirely amorphous. The di-urethanesils are thermally stable up to at least 200 ºC. At room temperature the conductivity maxima of the d-Ut(300)- and d-Ut(600)-based di-urethanesil families are located at n = 1 (approximately 2.0x10-6 and 7.4x10-5 Scm-1, respectively). At about 100 ºC, both these samples also exhibit the highest conductivity of the two electrolyte systems (approximately 1.6x10-4 and 1.0x10-3 Scm-1, respectively). The d-Ut(600)-based xerogel with n = 1 displays excellent redox stability., Fundação para a Ciência e a Tecnologia (FCT)

International audience; An organic molecule, (EtO)3Si(CH2)3NH(CO)NH–(CH2)12–NH(CO)NH(CH2)3Si(OEt)3, combining urea functionalities and a 12-carbon alkyl chain, underwent sol–gel reactions in the presence of an acid catalyst, a large excess of water and variable amounts of EuCl3, giving rise to the formation of crystalline hybrids through a self-directed organization process in which hydrogen bonding interactions play a key role. Three photoluminescent lamellar Eu3+-doped silsesquioxane hybrids incorporating 1.01, 1.83 and 15.04% Eu3+ were prepared and fully characterized. The lamellar hybrids are room temperature multi-wavelength emitters due to the convolution of the hybrid's emitting centres and the Eu3+ intra-4f6 transitions. Their emission colour can be easily tuned along the Commission Internationale d'Eclairage chromaticity diagram from the bluish-purple region to the pink area, either by changing the excitation wavelength or the Eu3+ amount. The Eu3+ first coordination shell is very similar for the three photoluminescent lamellar Eu3+-doped silsesquioxane hybrids incorporating oxygen atoms of the carbonyl group, Cl atoms and water molecules, despite the minor variations found in the 5D0 quantum efficiency (16.3–19.2), number of water molecules (1.7–2.0) and experimental intensity 2 parameter (8.9–10.1 × 10-20 cm2) with the increase of Eu3+ content.