Institute of Polymers, Composites and Biomaterials

A new hybrid nanocomposite for wastewater treatment was developed using hemp shiv fibers coated with ZnO nanolayers. Macro hemp shives were selected for their adsorption capacity and sustainability, while ZnO provided photocatalytic activity. Low-temperature atomic layer deposition (ALD) anchored ZnO nanolayers with controlled thicknesses (30, 70, 90 nm) onto hydroxyl groups on the hemp shives' surface. The effect of the ZnO thickness on adsorption and photocatalytic performance toward water organic pollutants was systematically investigated. Characterization included spectroscopic ellipsometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) with electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED), X-ray diffraction (XRD), thermogravimetric analysis (TGA), N 2 adsorption-desorption analysis, and Fourier transform infrared spectroscopy (FTIR). Methylene blue (MB) adsorption kinetics showed ZnO coatings partially shield the intrinsic adsorption aptitude of pure porous fibers' surface, with a shielding increasing with the ZnO thickness. Photocatalytic activity under UV irradiation was evaluated using three emergent water pollutants: MB dye, sodium dodecyl sulfate (SDS), and phenol. Hemp shives coated with a 30 nm-thick ZnO layer exhibited the highest degradation efficiencies for all the tested pollutants (about 70% after 4 h of light irradiation). Recycling tests confirmed material stability, with preserved ZnO coating and crystal structure after repeated use. Scavenger experiments indicated both radicals and photo-generated holes contribute to photocatalytic mechanism. The synergistic combination of adsorption and photocatalysis makes ZnO-coated hemp shives a promising and sustainable material for advanced wastewater treatment. • ZnO nanolayers were deposited on hemp shives via low-temperature ALD. • MB adsorption followed a pseudo-second order model, typical of chemisorption. • MB dye, SDS surfactant and phenol were efficiently degraded under UV irradiation. • Hybrid nanocomposite combined adsorption and photocatalytic pollutant degradation. • Sustainable ZnO/hemp shives offer a stable and eco-friendly solution for wastewater treatment.

Ultrathin two-dimensional (2D) coatings exhibit functional properties that are strongly defined by morphological features such as sheet edges, fracture sites, overlaps, folds, and local thickness variations, which are often difficult to resolve using conventional scanning electron microscopy (SEM) configurations. Here, we introduce a grazing-incidence SEM approach based on controlled sample tilting close to 90° for enhancing surface sensitivity and morphological feature detectability in ultrathin coatings. The method is proved on colloidal MoS2 nanosheet coatings prepared by liquid-phase exfoliation. Optical absorption spectroscopy confirms the presence of mono- and few-layer MoS2 nanosheets in the dispersion, confirming the ultrathin nature of the deposited coating. Compared to standard 0° imaging, grazing-incidence SEM reveals clearer boundaries and discontinuities. Quantitative Sobel-based image analysis supports these observations, showing an increase in edge density from 5.9% to 7.6% and in average gradient magnitude from 0.151 to 0.172 a.u. under grazing incidence, indicating a higher amount of retrievable morphological information. The proposed approach relies only on standard stage tilting and provides a broadly applicable framework for the surface-sensitive morphological characterization of ultrathin 2D coatings and thin films.

ABSTRACT In this work, we report the synthesis and characterization of non‐isocyanate polyhydroxyurethanes (PHUs) derived from resorcinol bis(cyclocarbonate) (RCC). The PHUs were obtained through polyaddition between RCC and two aliphatic diamines, namely isophoronediamine and Priamine 1075 (a commercial vegetal based diamine), selected due their eco‐friendliness, under mild conditions, without the use of toxic isocyanates and catalysts. The resulting materials were characterized by FTIR, NMR spectroscopy, GPC, DSC, and TGA to evaluate their chemical structure, molecular weight distribution, and thermal properties. Then, the processability of the synthesized PHUs was assessed and further functional characterizations, such as mechanical and viscoelastic properties, swelling and water contact angle tests, were performed. Finally, the RCC based PHUs were tested as potential adhesives for aluminium, polymer composite, and wood substrates. All the results highlight that RCC based PHUs are promising sustainable alternatives to fossil‐based polyurethanes.

Material extrusion additive manufacturing (MEAM) exhibits promising capabilities due to its high customization options. However, warpage emerges as a primary challenge hindering the widespread adoption of MEAM for mass production. This study focuses on investigating warpage in selected grades of propene-ethylene copolymers and a polypropylene homopolymer during MEAM. The influence of ethylene content on crystallinity was assessed using thermal analysis, and warpage was evaluated for rectangular parts, made of either one or two layers. Wide-angle X-ray diffraction was employed to analyse polymorphism, confirming the presence of α-phase. In situ infra-red camera measurements provided insights into the cooling profiles of the printed geometry. and two-layer prints, results show that increasing the ethylene content decreases crystallinity, and consequently, warpage is also decreased. Warpage substantially increases when printing thicker parts, primarily due to non-simultaneous crystallization between layers, as evidenced by comparing the cooling profile with DSC-measured crystallization temperature. Increasing bed temperature mitigates warpages for all materials and layer counts. This phenomenon is mainly attributed to a slower crystallization kinetics and to a more rapid and extended relaxation process, which diminishes internal stresses, thereby limiting bending. The parameter ΔT B = T C − T B (difference between the crystallization temperature T C and the bed temperature T B ) was introduced to account for crystallization kinetics in relation to processing conditions. This parameter is proposed as a unified descriptor for warpage behaviour, as all the data collected with different materials and T B lay on two “mastercurves”, which are functions of the number of printed layers. It is thus convincingly shown that minimizing ΔT B leads to reduced warpage, due to the slowing down of the crystallization kinetics and relaxation of internal stresses. • Ethylene Content Reduces Warpage: For the copolymers studied, increasing the ethylene content was found to decrease the material's crystallinity, which directly resulted in a reduction in part warpage. • Higher Bed Temperature Mitigates Warpage: Increasing the print bed temperature proved to be an effective strategy for reducing warpage across all tested materials and for both single and double-layer parts. This is attributed to slower crystallization kinetics and more time for internal stress relaxation. • Part Thickness Increases Warpage: Warpage was observed to increase substantially when printing thicker parts (two layers versus one). The sources suggest this is primarily because the layers crystallize at different times. • A Unified Warpage Descriptor (ΔTB) was Identified: The study introduced a new parameter, ΔTB = TC − TB , representing the difference between the material's crystallization temperature (TC) and the print bed temperature (TB). This parameter was proposed as a unified way to describe and predict warpage behavior. • Minimizing ΔTB is Key to Reducing Warpage: The research convincingly showed that minimizing the ΔTB value leads to reduced warpage. When plotted against this parameter, all the data from different materials and bed temperatures aligned on two "mastercurves," one for each part thickness, validating ΔTB as a reliable predictor.

ABSTRACTConcentrated growth factor (CGF), a blood‐derived autologous biomaterial, is increasingly utilised in regenerative medicine and, recently, in cancer‐related surgeries. Rich in cytokines, platelets, nucleated cells and fibrin scaffolds, CGF offers therapeutic promise but requires rigorous safety evaluation in oncology. This study explores the effects of CGF‐conditioned medium (CGF‐CM) on breast cancer (MCF7, MDA‐231) and osteosarcoma (SaOS‐2, MG‐63) cell lines. Our findings reveal that CGF‐CM selectively induces cytotoxic effects in MCF7 and SaOS‐2 cells, while no cytotoxicity was observed in MDA‐231 and MG‐63 cells. Early apoptosis in MCF7 and SaOS‐2 cells was accompanied by mitochondrial dysfunction, evidenced by an increased BAX/BCL‐2 ratio and cytochrome c release. CGF‐CM treatment also elevated ceramide and triglyceride levels, linking lipid metabolic changes to cancer cell death. Endoplasmic reticulum (ER) stress markers, ATF6 and XBP1, were significantly upregulated in MCF7 and SaOS‐2 cells, highlighting the role of ER stress in CGF‐CM‐induced cytotoxicity. Furthermore, CGF‐CM inhibited autophagic flux, as demonstrated by altered LC3 and p62 protein levels, disrupting cellular homeostasis and contributing to apoptosis. These findings highlight the selective cytotoxic effects of CGF‐CM on specific cancer cell lines. The intricate interplay between mitochondrial dysfunction, ER stress, autophagy inhibition and lipid metabolism highlights its complex mechanisms of action.

Printed potentiometric sensors require reliable solid contacts to provide stable and reproducible ion-selective electrodes. However, hampering fabrications and unfavorable maintenance often hinder their breakthrough on a commercial scale. Herein, we develop a solid-contact calcium-selective screen-printed electrode harnessing straightforward manufacturing based on the combination of carbon black (CB) and poly(3,4-ethylene dioxythiophene) doped with poly(sodium 4-styrenesulfonate) (PEDOT:PSS) as an ion-to-electron transducer. Drop-casting was used to simply deposit the CB layer, while PEDOT:PSS was rapidly electropolymerized (71 s) onto the working electrode to deliver affordable manufacturing of the printed electrode while ensuring valid potentiometric performance. Subsequently, the ion-selective membrane (ISM) and the polyvinyl butyral (PVB)-based reference membrane were, respectively, drop-cast onto the working electrode and reference electrode (RE). Upon the optimization of solid-contact layers, the solid-contact Ca2+-ISEs were investigated by evaluating their potentiometric performance versus a conventional RE. CB/PEDOT:PSS-modified screen-printed electrodes demonstrated a low-frequency capacitance of 55 μF, and an outstanding standard potential interelectrode reproducibility (±1 mV). The combination of both types of ion-to-electron transducers provided calcium detection in the linear range 10-1-10-7 M with a Nernstian sensitivity (28.3 ± 0.3 mV/decade), ensured over 28 days under dry storage. Furthermore, the absence of the water layer effect was also demonstrated. Lastly, the fully printed platform was assembled to achieve a miniaturized and easily field-deployable potentiometric device, consisting of CB/PEDOT:PSS/ISM configuration and PVB-based reference membrane on the working electrode and the RE, respectively. The resulted all-solid-state sensor revealed a Nernstian sensitivity with a 29.0 ± 0.5 mV/decade slope and a stable signal up to 72 h (drift = -0.2 mV/h). Analysis carried out using commercially available bottled water also demonstrated the sensor successful performance in the determination of calcium ion in real samples.

Chipless passive wireless sensors (CLPWSs) are gaining traction for applications requiring battery-free, compact, and wireless monitoring capabilities. Among these, strain sensors leveraging metasurfaces offer a promising approach due to their tunable electromagnetic responses. This study presents the fabrication and characterization of a frequency-selective CLPWS using a spraydeposited nanocomposite based on graphite nanoplatelets (GNPs) on a polyetherimide (PEI) substrate. Characterized of electrical conductivity, strain sensitivity, and electromagnetic response in the X band (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$8-12 \text{GHz}$</tex>) of samples with different composition have been performed to evaluate the best case for the fabrication of the sensor array. A maximum electrical conductivity (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 7.16 \times 10^{4} ~\mathrm{S} / \mathrm{m}$</tex>) was found for samples based on oriented GNPs at low frequencies (quasi-static condition). Strain sensitivity tests demonstrated a minimal resistance change under strain. X-band measurements and equivalent transmission line modeling were used to estimate material conductivity at high frequencies. The results highlight the feasibility of spraydeposited GNP-based metasurfaces for wireless strain sensing. Indeed, an array sensor of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10 \times 10 ~\text{cm}^{2}$</tex> has been fabricated and preliminary tested in X-band.

ABSTRACTIn this work, Opuntia (commonly called prickly pear cactus) was investigated as a source for reinforcing plant fibers, as it represents a low‐cost and widely available alternative to other commonly used natural fibers, such as kenaf, hemp, sisal, or flax. A fiber network that reflects the shape of the leaf structure can be found in the cladodes of Opuntia. Water retting was identified as the most promising method to extract the fiber network from the plant. Tensile tests and thermogravimetric analysis were performed on the extracted fibers to evaluate the quality of the extraction process. Different parameters such as time, surface exposure, and temperature were investigated to optimize the water retting process. The results indicate that an increase in surface exposure and higher water temperature leads to a reduction in time needed for fiber extraction. The extracted fibers were then embedded in a PLA matrix by compression molding to fabricate a fiber‐reinforced composite. The mechanical performance of the Opuntia fiber‐reinforced plastic was investigated. Analysis (particularly mechanical, optical and fiber volume content) indicates that the impregnating quality was insufficient, leading to a weak performance of the material.