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Refractory pollutants often exist in wastewater after photocatalysis. Here, experiments, gas chromatography-mass spectrometry (GC–MS) analysis and density functional theory (DFT) simulations were used to explain the different levels of photocatalytic degradation of organics in papermaking wastewater associated with two photocatalytic processes with the goal of improving environmental sustainability. The photocatalytic experiments of flocculation and SBR effluents of papermaking wastewater were studied in a reactor with nano-TiO2 colloid, followed by GC–MS analysis, and the different degradation levels of organics were explained based on DFT adsorption and photocatalysis simulations. The experimental results show that the total COD removal rates were 65.8% and 90.8% for the flocculation-photocatalysis and SBR-photocatalysis processes, and the resin acids and fatty acids in wastewater were classified as easily degradable pollutants and esters as refractory pollutants. The adsorption and photocatalysis simulations show that compared with dehydroabietic acid and pentadecanoic acid, the adsorption of glycerol monostearate by nano-TiO2 colloid is difficult, the reaction pathways for photocatalysis are complex and the band gap of TiO2 photocatalyst after adsorption is wide. The experimental and simulation results indicate that the different degradation levels are attributed to the difficulty of the adsorption and photocatalytic reactions of glycerol monostearate compared with the reactions of the other two easily degradable pollutants. Thus, the different photocatalytic degradation levels of organic pollutants in the two photocatalytic processes of papermaking wastewater indicate that sustainable photocatalytic technology could be applied to different types of industrial wastewater.

Sustainability in electronics has a growing importance due to, e.g. increasing electronic waste, and global and European sustainability goals. Printing technologies and use of paper as a substrate enable manufacturing of sustainable electronic devices for emerging applications, such as the multi-layer anti-counterfeit label presented in this paper. This device consisted of electrochromic display (ECD) element, NFC (near field communication) tag and circuitry, all fully roll-to-roll (R2R) printed and assembled on plastic-free paper substrate, thus leading to a sustainable and recyclable device. Our setup uses harvested energy from HF field of a smartphone or reader, to switch an electrochromic display after rectification to prove authenticity of a product. Our novelty is in upscaling the manufacturing process to be fully printable and R2R processable in high-throughput conditions simulating industrial environment, i.e. in pilot scale. The printing workflow consisted of 11 R2R printed layers, all done in sufficient quality and registration. The printed antennas showed sheet resistance values of 32.9±1.9 mΩ/sq. The final yield was almost 1500 fully printed devices, and in R2R assembly over 1400 labels were integrated with 96.5% yield. All the assembled tags were readable with mobile phone NFC reader. The optical contrast (ΔE*) measured for the ECDs was over 15 for all the printed displays, a progressive switching time with a colour change visible in less than 5 s. The smart tag is ITO-free, plastic-free, fully printed in R2R and has a good stability over 50 cycles and reversible colour change from light to dark blue.

International audience; ConspectusThe chemical study of materials from natural history and cultural heritage, which provide information for art history, archeology, or paleontology, presents a series of specific challenges. The complexity of these ancient and historical materials, which are chemically heterogeneous, the product of alteration processes, and inherently not reproducible, is a major obstacle to a thorough understanding of their making and long-term behavior (e.g., fossilization). These challenges required the development of methodologies and instruments coupling imaging and data processing approaches that are optimized for the specific properties of the materials. This Account discusses how these characteristics not only constrain their study but also open up specific innovative avenues for providing key historical information. Synchrotron methods have extensively been used since the late 1990s to study heritage objects, in particular for their potential to provide speciation information from excitation spectroscopies and to image complex heritage objects and samples in two and three dimensions at high resolution. We examine in practice how the identification of key intrinsic chemical specificities has offered fertile ground for the development of novel synchrotron approaches allowing a better stochastic description of the properties of ancient and historical materials. These developments encompass three main aspects: (1) The multiscale heterogeneity of these materials can provide an essential source of information in the development of probes targeting their multiple scales of homogeneity. (2) Chemical alteration can be described in many ways, e.g., by segmenting datasets in a semiquantitative way to jointly inform morphological and chemical transformation pathways. (3) The intrinsic individuality of chemical signatures in artifacts triggers the development of specific strategies, such as those focusing on weak signal detection. We propose a rereading of the advent of these new methodologies for analysis and characterization and examine how they have led to innovative strategies combining materials science, instrument development, history, and data science. In particular, we show that spectral imaging and the search for correlations in image datasets have provided a powerful way to address what archeologists have called the uncertainty and ambiguity of the material record. This approach has implications beyond synchrotron techniques and extends in particular to a series of rapidly developing approaches that couple spectral and spatial information, as in hyperspectral imaging and spatially resolved mass spectrometry. The preeminence of correlations holds promise for the future development of machine learning methods for processing data on historical objects. Beyond heritage, these developments are an original source of inspiration for the study of materials in many related fields, such as environmental, geochemical, or life sciences, which deal with systems whose alteration and heterogeneity cannot be neglected.

Cationic lanthanide complexes are generally able to spontaneously internalize into living cells. Following our previous works based on diMe-cyclen framework, a second generation of cationic water-soluble lanthanide complexes based on a constrained cross-bridged cyclam macrocycle functionalized with donor-p-conjugated picolinate antennas has been prepared with europium(III) and ytterbium(III). Their spectroscopic properties were thoroughly investigated in various solvents and rationalized with the help of DFT calculations. A significant improvement is observed in the case of the Eu3+ complex, while the Yb3+ analogous conserve an excellent brightness in aqueous solvent. Two-photon (2P) microscopy imaging experiments on living T24 human cancer cells confirmed the spontaneous internalization of the probes and images with good signal-to-noise have been obtained in the classical NIR-to-visible configuration with Eu3+ luminescent bioprobe and in the NIR-to-NIR with the Yb3+ one.

Cellulose nanofiber films (CNFF) were treated via a welding process using ionic liquids (ILs). Acid-base-conjugated ILs derived from 1,5-diazabicyclo[4.3.0]non-5-ene [DBN] and 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) were utilized. The removal efficiency of ILs from welded CNFF was assessed using liquid-state nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared spectroscopy (FTIR). The mechanical and physical properties of CNFF indicated surface plasticization of CNFF, which improved transparency. Upon treatment, the average CNFF toughness increased by 27%, and the films reached a Young's modulus of ∼5.8 GPa. These first attempts for IL "welding" show promise to tune the surfaces of biobased films, expanding the scope of properties for the production of new biobased materials in a green chemistry context. The results of this work are highly relevant to the fabrication of CNFFs using ionic liquids and related solvents. acceptedVersion

Recent years have seen an increased interest towards utilizing bio-based and biodegradable materials for barrier packaging applications. Most of the above said materials usually have certain shortcomings that discourage their adoption as a preferred material of choice. Nanocellulose falls into such category. It has excellent barrier against grease, mineral oils and oxygen, but poor tolerance against water vapor, which makes it unsuitable to be used at high humidity. In addition, nanocellulose suspensions' high viscosity and yield stress already at low solids content, and poor adhesion to substrates create additional challenges for high-speed processing. Polylactic acid (PLA) is another potential candidate that has a reasonably high tolerance against water vapor, but rather poor barrier against oxygen. The current work explores the possibility to combine both these materials into thin multilayer coatings onto paperboard. A custom-built slot-die was used to coat either microfibrillated cellulose (MFC) or cellulose nanocrystals (CNCs) onto pigment-coated baseboard in a continuous process. These were subsequently coated with PLA using a pilot scale extrusion coater. Low-density polyethylene (LDPE) was used as a reference extrusion coating. Cationic starch pre-coating and corona treatment improved the adhesion at nanocellulose/baseboard and nanocellulose/PLA interfaces, respectively. Water vapor transmission rate for nanocellulose + PLA coatings remained lower than the control PLA coating, even at a high relative humidity of 90% (38 oC). The multilayer coating had 98% lower oxygen transmission rate compared to just PLA coated baseboard and heptane vapor transmission rate reduced by 99% in comparison to baseboard. Grease barrier for nanocellulose + PLA coatings increased 5-fold compared to nanocellulose alone and 2-fold compared to PLA alone. This approach of processing nanocellulose and PLA into multiple layers utilizing slot-die and extrusion coating in tandem has the potential to produce a barrier packaging paper that is both 100% bio-based and biodegradable. publishedVersion

The development of new biocompatible, biodegradable functionalized biopolymers that can serve as scaffold for tissue regeneration or work as carriers for different bioactive molecules such as drugs, proteins, and enzymes remains a continuous challenge that need to be extensively explored. For this purpose, three water-soluble cellulose derivatives; namely 4(celluloseamino) butyric acid (CABA) 2(celluloseamino) succinic acid (CASA), and 3(celluloseamino) propane sulfonic acids (CAPSA) were synthesized from microcrystalline cellulose (MCC) via esterification with tosyl chloride that was followed by nucleophilic substitution by the proper aminoalkyl acid derivative. The products were characterized by elemental analyses, FTIR, 13C NMR spectroscopy. The thermal stability, surface morphology, and the elemental composition of the new ampholytic biopolymers were also studied by TGA, EDX-SEM. The new ampholytic cellulose derivatives were evaluated for their in vitro cytotoxicity on normal human retina cell line (RPE1) by MTT assay.

We systematically investigated the effect of film-forming polyvinyl alcohol and crosslinkers, glyoxal and ammonium zirconium carbonate, on the optical and surface properties of films produced from TEMPO-oxidized cellulose nanofibers (TOCNFs). In this regard, UV-light transmittance, surface roughness and wetting behavior of the films were assessed. Optimization was carried out as a function of film composition following the “random forest” machine learning algorithm for regression analysis. As a result, the design of tailor-made TOCNF-based films can be achieved with reduced experimental expenditure. We envision this approach to be useful in facilitating adoption of TOCNF for the design of emerging flexible electronics, and related platforms.

International audience; Hybrid perovskite thin films have demonstrated impressive performance for solar energy conversion and optoelectronic applications. However, further progress will benefit from a better knowledge of the intrinsic photophysics of materials. Here, the temperature-dependent emission properties of CH3NH3PbI3 single crystals are investigated and compared to those of thin polycrystalline films by means of steady-state and time-resolved photoluminescence spectroscopy. Single crystals photoluminescence present a sharp excitonic emission at high energy, with full width at half maximum of only 5 meV, assigned to free excitonic recombination. We highlight a strong thermal broadening of the free excitonic emission, due to exciton–LO-phonon coupling. The emission turned to be very short-lived with a subnanosecond dynamics, mainly induced by the fast trapping of the excitons. The free excitonic emission is completely absent of the thin film spectra, which are dominated by trap state bands.

Slippery, liquid-infused porous surfaces offer a promising route for producing omniphobic and anti-icing surfaces. Typically, these surfaces are made as a coating with expensive and time consuming assembly methods or with fluorinated films and oils. We report on a route for producing liquid-infused surfaces, which utilizes a liquid precursor fed oxygen-hydrogen flame to produce titania nanoparticles deposited directly on a low-density polyethylene film. This porous nanocoating, with thickness of several hundreds of nanometers, is then filled with silicone oil. The produced surfaces are shown to exhibit excellent anti-icing properties, with an ice adhesion strength of ∼12 kPa, which is an order of magnitude improvement when compared to the plain polyethylene film. The surface was also capable of maintaining this property even after cyclic icing testing. Slippery, liquid-infused porous surfaces (SLIPSs) are nature inspired surfaces that are designed to repel liquid and solid materials. These surfaces have been shown to pose anti-icing properties, which broadens the available end-uses from the chemical industry to arctic transportation and energy production. The method behind repellency of SLIPSs relies on preventing outside liquids from penetrating the surface structure to the Wenzel state. Instead, the slippery liquid within the porous solid supports the Cassie-Baxter state (instead of air, here the porous structure is filled with lubricant), where the reduced area of the porous solid surface is available to interact with the liquid or ice to be repelled. The difference between Wenzel and Cassie-Baxter states is illustrated in Figure 1. This phenomenon is exploited in many superhydrophobic surfaces where an air cushion is entrapped within the porous solid surface. As a result, spherical water drops easily roll off the surface (and have static contact angles larger than 150°). publishedVersion

This chapter reports the mechanical properties of starch‐based nanocomposite materials, considering that the starchy material can be used either as the continuous polymeric phase (matrix), or the nanodispersed phase (filler), or both. The first section of the chapter discusses the reinforcing effect of the different fillers used to improve the mechanical properties of thermoplastic starch, that is, inorganic clays, carbon nanotubes, and polysaccharide‐based (cellulose, starch) nanoparticles and attempts to give a critical comparison of the different reinforcements The second section talks about the reinforcing effect of starch nanocrystals, as well as the mechanisms proposed to explain it.