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We investigated the effects of solvent fractionation on the chemical structures of two commercial technical lignins. We compared the effect of Soxhlet and Kumagawa extraction. The aim of this work was to compare the impact of the methods and of the solvents on lignin characteristics. Our investigation confirmed the potentialities of fractionation techniques in refining lignin properties and narrowing the molecular weight distribution. Furthermore, our study revealed that the Kumagawa process enhances the capacity of oxygenated solvents (ethanol and tetrahydrofuran) to extract lignin that contains oxidized groups and is characterized by higher average molecular weights. Furthermore, the use of tetrahydrofuran after ethanol treatment enabled the isolation of lignin with a higher ratio between carbonyl and other oxidized groups. This result was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR)

An innovative consolidation strategy for degraded paper is presented based on the reversible application of cellulose nanocrystals as sustainable fillers to reinforce mechanical properties and resistance to further degradation. The compatibility and efficacy of the proposed consolidation treatment are assessed first on pure cellulose paper, used as a model, by reliable techniques such as field emission scanning electron microscopy, atomic force microscopy, tensile tests, X-ray powder diffraction, and Fourier transform infrared spectroscopy, evidencing the influence of the surface functionalization of nanocellulose on the consolidation and protection effects. Then, the consolidation technique is applied to real aged paper samples from Breviarium romanum ad usum Fratrum Minorum S.P. (1738), demonstrating the promising potential of the suggested approach. Amperometric measurements, carried out with a smart electrochemical tool developed in our laboratory, demonstrate the reversibility of the proposed treatment by removal of the nanocrystalline cellulose from the paper surface with a suitable cleaning hydrogel. This completely new feature of the consolidation treatment proposed here satisfies a pivotal requisite in cultural heritage conservation because the methodological requirement for the ″reversibility″ of any conservation measure is a fundamental goal for restorers. A paper artifact, in fact, is subject to a number of natural and man-made hazards, inducing continuous degradation. With time, monitoring and consolidation actions need to be often performed to ensure conservation, and this tends to modify the status quo and compromise the artifact integrity. Removable treatments can potentially avoid erosion of the artifact integrity.

Nanocellulose has received enormous scientific interest for its abundance, easy manufacturing, biodegradability, and low cost. Cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) are ideal candidates to replace plastic coating in the textile and paper industry. Thanks to their capacity to form an interconnected network kept together by hydrogen bonds, nanocelluloses perform an unprecedented strengthening action towards cellulose- and other fiber-based materials. Furthermore, nanocellulose use implies greener application procedures, such as deposition from water. The surface chemistry of nanocellulose plays a pivotal role in influencing the performance of the coating: tailored surface functionalization can introduce several properties, such as gas or grease barrier, hydrophobicity, antibacterial and anti-UV behavior. This review summarizes recent achievements in the use of nanocellulose for paper and textile coating, evidencing critical aspects of coating performances related to deposition technique, nanocellulose morphology, and surface functionalization. Furthermore, beyond focusing on the aspects strictly related to large-scale coating applications for paper and textile industries, this review includes recent achievements in the use of nanocellulose coating for the safeguarding of Cultural Heritage, an extremely noble and interesting emerging application of nanocellulose, focusing on consolidation of historical paper and archaeological textile. Finally, nanocellulose use in electronic devices as an electrode modifier is highlighted.

Cellulose nanomaterials have been widely investigated in the last decade, unveiling attractive properties for emerging applications. The ability of sulfated cellulose nanocrystals (CNCs) to guide the supramolecular organization of amphiphilic fullerene derivatives at the air/water interface has been recently highlighted. Here, we further investigated the assembly of Langmuir hybrid films that are based on the electrostatic interaction between cationic fulleropyrrolidines deposited at the air/water interface and anionic CNCs dispersed in the subphase, assessing the influence of additional negatively charged species that are dissolved in the water phase. By means of isotherm acquisition and spectroscopic measurements, we demonstrated that a tetra-sulfonated porphyrin, which was introduced in the subphase as anionic competitor, strongly inhibited the binding of CNCs to the floating fullerene layer. Nevertheless, despite the strong inhibition by anionic molecules, the mutual interaction between fulleropyrrolidines at the interface and the CNCs led to the assembly of robust hybrid films, which could be efficiently transferred onto solid substrates. Interestingly, ITO-electrodes that were modified with five-layer hybrid films exhibited enhanced electrical capacitance and produced anodic photocurrents at 0.4 V vs Ag/AgCl, whose intensity (230 nA/cm2) proved to be four times higher than the one that was observed with the sole fullerene derivative (60 nA/cm2).

Cellulose nanocrystals (CNCs) are renewable, sustainable and biocompatible nanomaterials, which have gained great attention in last years for their potentialities in several fields of application. With their polyelectrolyte behaviour, sulphated CNCs are suitable to produce multilayered architectures with cationic molecules. In this work, we have investigated the ability of anionic CNCs to assist the two-dimensional organization of two cationic fulleropyrrolidines at the air/water interface, leading to hybrid Langmuir-Schaeurofer films with improved (photo)electrical properties. We demonstrated that CNCs interact with the fulleropyrrolidines at the air/water interface, favouring the assembly of organized hybrid C-60/CNC films. The transfer efficiency of Langmuir layers and the morphological regularity of supported films proved to be influenced by the extent of positive charge on the fullerene counterpart. Interestingly, the electrochemical characterization of hybrid films revealed that sulphated nanocellulose strongly improves the electrical properties of organized fullerene layers, by increasing their conductivity and favouring the hydrogen evolution reaction. Moreover, the well-established C-60 photoactivity proved to be enhanced by CNCs, as demonstrated by the higher intensity of photocurrents. This outstanding nanocellulose impact on fullerene film electrical properties paves the way to the development of more performing C-60-based electrochemical devices, able to better exploit the unique properties of carbon nanostructures. (C) 2020 Elsevier Ltd. All rights reserved.

Lignin is an abundant biopolymer deriving from industrial pulping processes of lignocellulosic biomass. Despite the huge amount of yearly produced lignin waste, it finds scarce application as a fine material and is usually destined to be combusted in thermochemical plants to feed, with low efficiency, other industrial processes. So far, the use of lignin in materials science is limited by the scarce knowledge of its molecular structure and properties, depending also on its isolation method. However, lignin represents an intriguing feedstock of organic material. Here, the structural and chemical-physical characteristics of two kraft lignins, L1 and L2, are analyzed. First, several molecular characterization techniques, such as attenuated total reflectance - Fourier transform infrared spectroscopy, elemental analyses, gel permeation chromatography, evolved gas analysis-mass spectrometry, UV–vis, 31P- and 13C- nuclear magnetic resonance spectroscopies are applied to get insights into their different structures and their degree of molecular degradation. Then, their efficient application as gate dielectric materials is demonstrated for organic field-effect transistors, finding the increased capacity of L1 with respect to L2 in triggering functional and efficient devices with both p-type and n-type organic semiconductor molecules. Version of record

Cellulose nanocrystals (CNCs) represent intriguing biopolymeric nanocrystalline materials, that are biocompatible, sustainable and renewable, can be chemically functionalized and are endowed with exceptional mechanical properties. Recently, studies have been performed to prepare CNCs with extraordinary photophysical properties, also by means of their functionalization with organic light-emitting fluorophores. In this paper, we used the reductive amination reaction to chemically bind 4-(1-pyrenyl)butanamine selectively to the reducing termini of sulfated or neutral CNCs (S_CNC and N_CNC) obtained from sulfuric acid or hydrochloric acid hydrolysis. The functionalization reaction is simple and straightforward, and it induces the appearance of the typical pyrene emission profile in the functionalized materials. After a characterization of the new materials performed by ATR-FTIR and fluorescence spectroscopies, we demonstrate luminescence quenching of the decorated N_CNC by copper (II) sulfate, hypothesizing for these new functionalized materials an application in water purification technologies.

Purpose: To investigate the relationships between white matter hyperintensities (WMH) and hippocampal volume and their influence on brain networks by using resting-state functional connectivity (rs-fc) magnetic resonance (MR) according to their localization. Methods: In this exploratory cross-sectional study, 38 subjects from the public "Leipzig Study for Mind/Body/Emotion Interactions"(LEMON) data set were selected. Morphometric analyses of both WMH burden and the total hippocampal relative volume (tHRV) were performed for each subject with two automated software. The WMH were then categorized as total (tWMH), periventricular (pvWMH), deep (dWMH), and juxtacortical (jcWMH). Spearman's correlation analyses were performed to evaluate the relationships between the following variables: age, tWMH, pvWMH, dWMH, jcWMH, and tHRV. Subsequently, three different rs-fc MR group analyses were performed using a multiple regression model that included age, pvWMH, dWMH, and jcWMH as second-level covariates. The graph theoretical analysis was applied to evaluate the effects of pvWMH (analysis 1), jcWMH (analysis 2), and dWMH (analysis 3). Results: Spearman's correlation analysis revealed several statistically significant (p < 0.05) positive and negative correlations, in particular positive between age and tWMH, and negative between dWMH and tHRV. rs-fc MR analysis 1 and 2 did not reveal statistically significant results; analysis 3 revealed that dWMH influenced network properties of several cerebral regions, in particular global and local efficiency of both the hippocampi. Conclusion: The localization of WMH influences brain activity in healthy subjects. In particular, dWMH are inversely correlated with tHRV and influence several properties of different cerebral areas, included both the hippocampi. In this exploratory research we evidenced how both the load and the localization of white matter hyperintensities influence brain activity; in particular, we evidenced an inverse correlation between the volume of the deep white matter hyperintensities and hippocampal volume, as well as a direct influence on the connectivity properties of this important cerebral region. This finding represent a new element for understanding the effects of white matter hyperintensities on brain networking, and a cue that could be taken into account for possible future studies investigating brain connectivity and cognitive functions in healthy and pathological conditions.

White matter hyperintensities (WMH) are common findings that can be found in physiological ageing. Several studies suggest that the disruption of white matter tracts included in WMH could induce abnormal functioning of the respective linked cortical structures, with consequent repercussion on the cerebral functions, included the cognitive sphere. In this cross-sectional research, we analysed the effects of the total WMH burden (tWMHb) on resting-state functional magnetic resonance imaging (rs-fMRI) and cognition. Functional and structural MR data, as well as the scores of the trail making test subtests A (TMT-A) and B (TMT-B) of 75 healthy patients, were extracted from the public available Leipzig Study for Mind-Body-Emotion Interactions dataset. tWMHb was extracted from structural data. Spearman's correlation analyses were made for investigating correlations between WMHb and the scores of the cognitive tests. The fractional amplitude of low-frequency fluctuations (fALFF) method was applied for analysing the rs-fMRI data, adopting a multiple regression model for studying the effects of tWMHb on brain activity. Three different subanalyses were conducted using different statistical methods. We observed statistically significant correlations between WMHb and the scores of the cognitive tests. The fALFF analysis revealed that tWMHb is associated with the reduction of regional neural activity of several brain areas (in particular the prefrontal cortex, precuneus and cerebellar crus I/II). We conclude that our findings clarify better the relationships between WMH and cognitive impairment, evidencing that tWMHb is associated with impairments of the neurocognitive function in healthy subjects by inducing a diffuse reduction of the neural activity.

In this work we demonstrated that the peripherical thioacetylation of a bithiophene-DPP molecule can greatly influence the solid-state properties triggering the formation of NIR emitting

Cellulose nanopaper (CNP) is a fascinating free-standing thin film material, prepared from renewable nanocellulose and displaying special properties such as transparency, haze, thermal stability, mechanical strength, and flexibility. The nanostructured nature of CNP enables gas barrier films and high specific surface areas for interface functionalization. Re-engineering CNP by physical and chemical design allows to tailor its properties, enabling hydrophobic and transparent paper, smart sensors, substrates for optoelectronic devices, and conductive or luminescent papers. This chapter rationally describes the chemical and physical manipulations that can be performed on CNP to modulate its properties, classifying them as: covalent chemical modification on nanocellulose before processing them into nanopaper thin films; covalent chemical modification on CNP surface; and noncovalent modification of CNP by coating or blending nanocellulose with other materials.