Ionic liquids (ILs) and metal-organic frameworks (MOFs) have been combined among themselves and with polymer matrices to obtain composites that are able to be applied in different fields, ranging from sensors and actuators to energy devices. Besides the great efforts devoted to the development and application of those composites, detailed information regarding the internal organization of IL and MOF within the composites is still needed, in order to further tune material properties toward applications. Thus, the present work reports on the development of polymer composites based on the MOF Basolite C300-HKUST-1 and different imidazolium-based ILs ([Bmim]-[FeCl4], [Bmim]-[N-(CN)2], and [Bmim]-[SCN]) with different types of anions incorporated into a fluorinated poly-(vinylidene fluoride) (PVDF) polymer matrix. Ternary MOF/IL/PVDF composites have been prepared by solvent casting incorporating 20 wt % of the different ILs together with 20 wt % of HKUST. The influence of MOF and ILs into the morphological, physical-chemical and electrical properties of the composites was evaluated. No significant morphological differences were observed upon the incorporation of the different ILs and MOF into the PVDF, all displaying compact microstructures. However, independently of the IL type, an increase in the electroactive β phase of the polymer was observed, with the highest amount in the ternary composite containing the IL [Bmim]-[N-(CN)2], reaching approximately 74%. Furthermore, the degree of crystallinity of the composites increased with the IL incorporation. The electrical properties of the different ternary composites revealed an increase in the conductivity from 1.06 × 10-13 S·cm-1 for the pristine polymer to 7.48 × 10-9 S·cm-1, 7.52 × 10-7 S·cm-1, and 3.11 × 10-9 S·cm-1 for the ILs [Bmim]-[FeCl4], [Bmim]-[N-(CN)2], and [Bmim]-[SCN]-containing samples, respectively. The internal structure of the composite samples was evaluated, showing that the presence of [Bmim]-[SCN] and [Bmim]-[FeCl4] in the ternary composites leads to a destruction of the MOF structure as well as to large-size inhomogeneities, indicating that IL accumulated with parts of the destroyed MOF as well as IL agglomeration through the matrix. These findings demonstrate the ability to tailor the electroactive phase content and conductivity through IL selection, which is highly relevant for functional applications. In particular, the developed composites hold strong potential for use in flexible sensors, electrochemical energy storage systems, and responsive devices where ionic conductivity and structural organization at the nanoscale are relevant.

Due to their ionic composition, adaptability, and responsiveness to different stimuli, ionic liquids (ILs) are among the most suitable systems to develop smart stimuli‐responsive materials, to be applied as sensors and actuators, in particular when incorporated into a polymer matrix, with improved processability and integration into devices. In the present work, films based on the IL 1‐butyl‐3‐methylimidazolium tetrachloroferrate ([Bmim][FeCl 4 ]) incorporated into a poly(vinylidene fluoride) (PVDF) matrix with different concentrations (5, 10, and 20 wt.%) are prepared by solvent casting. Samples are used for the fabrication by doctor blade and screen printing of a fully printed flexoelectric device suitable for bending and pressure monitoring. The highest sensing response is observed for the composites incorporating 20 wt.% IL content, leading to a bending angle and pressure sensitivity of 7.29 µV/° and 0.7 µV kPa −1 , respectively. The technological potential of the developed materials and their flexoionic response, combined with their processability by printing techniques, has been demonstrated in a finger movement monitoring system, opening the possibility of application in areas including wearables and robotics.

Smart multifunctional materials have been increasingly applied in different fields of knowledge. In particular, photoluminescent materials have been explored for displays, radiation detection, lamps or anti-counterfeiting applications, among others. This work reports the development of photoluminescent materials based on poly (vinylidene fluoride) (PVDF) polymer incorporating different contents (0, 5, 10, and 20 % w/w) of the luminescent ionic liquid (IL) 1-butyl-3-methylimidazolium tetrakis(thenoyltrifluoroacetonato)europate(III) ([Bmim] [Eu(tta)4]). The inclusion of the IL induced an increase of roughness and a slightly porous structure. No changes occur in the PVDF chemical structure and thermal behaviour. A decrease in the Young Modulus was observed, from 1.75x103 +/- 1.56x102 to 5.09x102 +/- 2.07x102 MPa for the sample incorporating 20 % w/w of IL which acted as a plasticizer. Further, the presence of ionic charges promoted an increase in electrical conductivity. The influence of IL content on the luminance was evaluated and a proof of concept demonstrating the potential of the composites as a UV-vis filter converter is provided.

Ionic liquids (ILs) have been combined with different polymer matrixes to develop smart and functional materials. Due to their versatility, hybrid materials with specific tailor made properties can be obtained, including printable thermochromic materials, with a strong potential for sensing applications. In this context, the thermochromic IL bis(1-butyl-3-methylimidazolium) tetrachloronickelate ([Bmim]2[NiCl4]) was incorporated into a biopolymer derived matrix, poly(L-lactic acid) (PLLA) in distinct concentrations up to 40% wt. aiming to develop environmentally friendly screen-printable printable thermochromic materials. The addition of IL does not induce changes on the thermal properties of the material. On the other hand, the incorporation of the IL leads to the development of a porous structure in the films, a mechanical plasticizing effect in the polymer matrix, revealed by the decrease of the Young's Modulus from 1110 +/- 66 MPa to 572 +/- 41 MPa and a increase in the electrical conductivity from 2.89x10-14 S center dot cm(-1) to 2.66x10-8 S center dot cm(-1), for PLLA and the samples with 40 % wt. of IL, respectively. Finally, the thermochromic material was screen-printed on various substrates, including paper, polyethylene terephthalate (PET), textile and wood, opening the way for a wide range of applications.

During the last few decades, major advances have been made in photovoltaic systems based on Cu(In,Ga)Se2 chalcopyrite. However, the most efficient photovoltaic cells are processed under high-energy-demanding vacuum conditions. To lower the costs and facilitate high-throughput production, printing/coating processes are proving to be effective solutions. This work combined printing, coating, and chemical bath deposition processes of photoabsorber, buffer, and transparent conductive layers for the development of solution-processed photovoltaic systems. Using a sustainable approach, all inks were formulated using water and ethanol as solvents. Screen printing of the photoabsorber on fluorine-doped tin-oxide-coated glass followed by selenization, chemical bath deposition of the cadmium sulfide buffer, and final sputtering of the intrinsic zinc oxide and aluminum-doped zinc oxide top conductive layers delivered a 6.6% maximum efficiency solar cell, a record for screen-printed Cu(In,Ga)Se2 solar cells. On the other hand, the all-non-vacuum-processed device with spray-coated intrinsic zinc-oxide- and tin-doped indium oxide top conductive layers delivered a 2.2% efficiency. The given approaches represent relevant steps towards the fabrication of sustainable and efficient Cu(In,Ga)Se2 solar cells.

•Sodium alginate (SA) based materials incorporating luminescent compounds were produced.•The fibers morphology, physico-chemical and thermal properties were determined.•The composite SA/[Bmim][Eu(tta)4] developed the highest luminescent properties.•The luminescent eco-friendly composites are suitable for anti-counterfeiting and soft actuators.

This work focuses on the combination of multifunctional photocatalytic and adsorbent materials in a unique polymeric membrane. For this purpose, Au/TiO2 and Y2(CO3)3 nanoparticles were immobilised onto a poly (vinylidene fluoride-hexafluoropropylene), (PVDF-HFP) membrane, and the physical-chemical characterisation of these materials was performed, as well as pollutant removal efficiency. An efficient TiO2 functionalisation with gold nanoparticles was achieved, endowing these particles with the capability to absorb visible radiation absorption. A favourable porous structure was obtained for the membranes, with an average pore size of 4 μm, and the nanoparticles immobilisation did not alter the chemical properties of the polymeric membrane. The produced hybrid materials, including both the Au/TiO2 and Y2(CO3)3 nanoparticles, presented an efficiency of 57% in the degradation of norfloxacin (5 mg/L) under ultraviolet radiation for 120 min, 80% under visible radiation for 300 min, and 58% in arsenic adsorption for 240 min. These membranes represent a new multifunctional platform for removing several pollutants, which may allow their incorporation in more efficient and less energy-consuming water treatment processes favouring its application, even in low energy resources countries.

Natural or industrial hexavalent chromium water pollution continues to be a worldwide unresolved threat. Today, there is intense research on new active and cost-effective sorbents for Cr(VI), but most still exhibit a critical limitation: their powdered nature makes their recovery from water cost and energy consuming. In this work, Al(OH)3, MIL-88-B(Fe), and UiO-66-NH2 Cr(VI) sorbents were immobilized into a poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymeric substrate to develop an easily reactivable and reusable water filtering technology. The immobilization of the sorbents into the PVDF-HFP porous matrix modified the macro and meso-porous structure of the polymeric matrix, tuning in parallel its wettability. Although a partial blocking of the Cr(VI) adsorptive capacity was observed for of Al(OH)3 and MIL-88-B(Fe) when immobilized into composite membranes, PVDF-HFP/UiO-66-NH2 filter (i) exceeded the full capacity of the non-immobilized sorbent to trap Cr(VI), (ii) could be reactivated and reusable, and (iii) it was fully functional when applied in real water effluents.

Abstract Nanocomposite membranes (NCMs) of poly(vinylidene fluoride‐hexafluoropropylene), PVDF‐HFP, with different yttrium carbonate and magnetite loadings, are prepared, and their dual adsorption capacity over neutral arsenite and anionic arsenate species is evaluated. The nanoparticles (NPs) and the corresponding NCMs are fully characterized in morphology, microstructure, thermal, and surface properties. The nanocomposite membranes present a micrometric porous structure with a homogeneous distribution of the active nanoparticles. Chemical, thermal, and water‐contact angle characteristics of the NCMs point out that they maintain the chemical and thermal stability of the polymer while improving the wettability. Arsenic removal depends on NP loading and pH of the media. For instance, efficiencies close to 100% are achieved for arsenate species under acidic conditions, while adsorption capacity over arsenite is also incremented above 80%. Fe3O4/PVDF‐HFP nanocomposite shows a dual affinity for the adsorption of As(III) and As(V) species, with the maximum adsorption capacities of 92.82 and 137.08 mg g−1, respectively. In addition, both NCMs are easily activated and reused without significant efficiency loss. Consequently, the nanocomposite membranes represent low‐cost, reusable, and efficient water remediation systems suitable for the long‐term removal of As(III) and As(V) under conditions mimicking real polluted surface and groundwater.

A membrane reactor (MR), combining adsorption and membrane separation processes, represents a new hybrid and promising technology for arsenic-contaminated water treatment. This work reports on nanocomposite filters (NCFs) based on poly (vinylidene fluoride-hexafluoropropylene), PVDF-HFP, containing yttrium carbonate (Y-2(CO3)(3)) and magnetite (Fe3O4) to adsorb neutral and anionic species of As(III) and As(V), in an up-scaled membrane reactor. The nano-sorbents and the NCFs were thoroughly characterised concerning morphological and physical-chemical properties. Incorporating the nano-sorbents does not affect the main characteristics of the NCF. Flow rate and pH of the media are the main parameters affecting the adsorption efficiency: lower flow rates and acidic pH are the most favorable conditions for dual As(III) and As(V) adsorption. Y@Fe3O4/PVDF-HFP adsorption follows pseudo-second-order kinetics described by Langmuir isotherm model, reaching maximum absorption capacities of 101.9 and 212.8 mg/g for As(III) and As(V), respectively. In addition, the NCFs proved to be effective for the removal of As(III) and As(V) in treated effluents and easily reactivated and reused without significant efficiency losses. Thus, Y@Fe3O4/PVDF-HFP nanocomposite filters and the designed up-scaled membrane reactor represent a straightforward, efficient, reusable, and low-cost alternative for a continuous treatment process for As(III) and As(V) remediation in real condition effluents sources.

This systematic study includes physical–chemical characterisation of nanomaterials, arsenic adsorption assays, adsorption mechanism proposal, and acute toxicity assays with Daphnia magna.

Counterfeiting is a global ever‐growing problem of immense magnitude that represents a menace to security, economy, and health at a worldwide level. Herein, a new luminescent security ink composed of poly(vinylidene fluoride) (PVDF) and the home‐made ionic liquid (IL) 1‐butyl‐3‐methylimidazolium tetra(thenoyltrifluoroacetonato)europate(III) ([Bmim][Eu(tta)4]) is reported. The optimized PVDF/[Bmim][Eu(tta)4] composite is processed by the doctor blade method as a micrometer‐thick film invisible under white light, with porous texture. The material exhibits high thermal stability, high chemical stability (inertness with respect to ethanol), high photostability, and intense red emission when excited with long UV radiation (365 nm) with a maximum quantum yield value of 0.10 ± 0.01. A test of the PVDF/[Bmim][Eu(tta)4] ink screen‐printed on a medical N95 protection mask performed under irradiation with white light and with a commercial 365 nm LED demonstrates its suitability to combat fraud. The exciting possibilities offered by PVDF/luminescent IL pair in terms of chemical modification of PVDF (copolymerization or functionalization) and IL (cation type/lanthanide ion/ligand type) for the tuning of the ink properties allow envisaging the production of tailor‐made tri‐ or biluminescent security inks, for authentication purposes.

This work reports on the evaluation of the thermal degradation of poly(vinylidene fluoride) (PVDF) and PVDF copolymer (PVDF-TrFE, PVDF-HFP and PVDF-CTFE) composite films with different imidazolium ionic liquids (ILs). The influence of the IL type, including cation and anion type, cation chain length and content up to 40 wt% were evaluated. Independently of the fluorinated polymer type, all neat samples present a single degradation step. Upon the incorporation of the IL [C2mim][TFSI] into the different polymers, a decrease in the thermal stability occurs, indicating the IL imidazolium interaction with the CH2-CF2 groups of the fluorinated matrix. Further, it was stablished that the thermal stability of the composite material decreases with increasing cation chain length. The Ozawa-Flynn-Wall and Kissinger models were applied to evaluate the activation energies of the samples during isothermal experiments, showing that the thermal degradation activation energy ranges from 161 +/- 6 kJ mol-1 ([C2mim][TFSI]/PVDF) to 131 +/- 14 kJ mol-1 ([C2mim][TFSI]/PVDF-CTFE). No large differences were observed on the effect of IL inclusion in PVDF, PVDF-TrFE, PVDF-HFP and PVDF-CTFE polymer matrices.

Given the societal concerns about the use of toxic chemicals and costly fabrication of functional materials and devices for photovoltaic applications, it is important to develop alternative sustainable methodologies. Previous studies have shown that cost-effective printing fabrication of Cu(In,Ga)Se2 thin film photovoltaics represents an interesting alternative to energy-demanding vacuum-based deposition methods, commonly used to produce Cu(In,Ga)Se2 photovoltaics. To enrich the field of printed Cu(In,Ga)Se2 photoabsorber thin films and to develop associated eco-friendly solutions, two novel inks, consisting of non-toxic reagents and readily available oxide materials, are reported. Screen printing of the inks over fluorine-doped tin oxide conductive substrates followed by swift selenization of the resultant patterns provides a straightforward route to phase-pure, uniform, and compact Cu(In,Ga)Se2 films with thickness and band gap energies ranging from 2.5 µm to 3.5 µm and from 0.97 eV to 1.08 eV, respectively. The present approach represents an important step forward in the sustainable fabrication of Cu(In,Ga)Se2 photovoltaics, where the physical properties of the photoabsorber can be easily adjusted by tuning the conditions of the screen printing process and the metal ratios in the inks.

This work reports on the production of poly(vinylidene fluoride) (PVDF) membranes by non-solvent induced phase separation (NIPS) using N,N-dimethylformamide (DMF) as solvent and water as non-solvent. The influence of the processing conditions in the morphology, surface characteristics, structure, thermal and mechanical properties were evaluated for polymer dissolution temperatures between 25 and 150 °C and conditioning time between 0 and 10 min. Finger-like pore morphology was obtained for all membranes and increasing the polymer dissolution temperature led to an increase in the average pore size (≈0.9 and 2.1 µm), porosity (≈50 to 90%) and water contact angle (up to 80°), in turn decreasing the β PVDF content (≈67 to 20%) with the degree of crystallinity remaining approximately constant (≈56%). The conditioning time did not significantly affect the polymer properties studied. Thus, the control of NIPS parameters proved to be suitable for tailoring PVDF membrane properties.

Environmentally friendly synthesis of Cu(In,Ga)Se2 (CIGS) nanoparticles (NPs) is pivotal for producing sustainable photocatalytic compounds to be applied in the remediation of contaminants of emerging concern from water. To this end, we herein report an aqueous synthesis of CIGS NPs, followed by annealing, to give access to phase-pure CIGS crystals with chalcopyrite structure and no signs of secondary phases. Morphological and compositional characterization revealed NPs with an average size of 10-35 nm and uniform distribution of Cu, In, Ga, and Se elements. In addition, the first aqueous large-scale synthesis of CIGS NPs is developed by up-scaling the synthesis procedure, resulting in 5 g of highly crystalline nanoparticles exhibiting an ideal optical band gap of 1.14 eV. The as-synthesized NPs proved the ability to remove 71 and 83% of a contaminant of emerging concern, ciprofloxacin (CIP), under ultraviolet (UV) and visible (Vis) radiations, respectively.

During the last few decades, the interest over chalcopyrite and related photovoltaics has been growing due the outstanding structural and electrical properties of the thin-film Cu(In,Ga)Se2 photoabsorber. More recently, thin film deposition through solution processing has gained increasing attention from the industry, due to the potential low-cost and high-throughput production. To this end, the elimination of the selenization procedure in the synthesis of Cu(In,Ga)Se2 nanoparticles with following dispersion into ink formulations for printing/coating deposition processes are of high relevance. However, most of the reported syntheses procedures give access to tetragonal chalcopyrite Cu(In,Ga)Se2 nanoparticles, whereas methods to obtain other structures are scarce. Herein, we report a large-scale synthesis of high-quality Cu(In,Ga)Se2 nanoparticles with wurtzite hexagonal structure, with sizes of 10–70 nm, wide absorption in visible to near-infrared regions, and [Cu]/[In + Ga] ≈ 0.8 and [Ga]/[Ga + In] ≈ 0.3 metal ratios. The inclusion of the synthesized NPs into a water-based ink formulation for screen printing deposition results in thin films with homogenous thickness of ≈4.5 µm, paving the way towards environmentally friendly roll-to-roll production of photovoltaic systems.

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 °C, were subjected to several post-thermal treatments at 70, 90, 120 and 140 °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 °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 °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 °C and thermally treated at 140 °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 authors wish to make changes to the published paper [...].

Emerging pollutants represent a new global problem for water quality. As these compounds get into the environment, they cause severe threats to aquatic environments and human health and are typically resistant to conventional wastewater treatments. In this work, TiO2 nanoparticles surface was functionalized with silver (Ag) nanoparticles, and solvent cast and electrospun membranes of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared with different concentrations of TiO2 and Ag-TiO2 to produce a multifunctional material. The photocatalytic activity of the nanocomposites was evaluated through the degradation of norfloxacin under ultraviolet (UV) and visible radiation. It is shown that nanocomposites with Ag-TiO2 show the highest degradation efficiencies: 64.2% under UV and 80.7% under visible radiation, for 90 and 300 min, respectively. Furthermore, the recyclability of the membranes has also been demonstrated. Finally, it is shown the antimicrobial activity of the nanocomposite membranes, demonstrating the suitability of the Ag-TiO2/PVDF-HFP nanocomposites as multifunctional photocatalytic and antimicrobial membranes for water remediation applications. (C) 2020 Elsevier Ltd. All rights reserved.