Design of responsive films using phenylurea modified chitosan and Viburnum tinus L. extract as natural indicator
Mouad El Mouzahim, Alessandro Pedrini, Enrico Dalcanale, N. Riboni, F. Bianchi, A. Jorge Parola, Roberta Pinalli
Published online: 13 February 2026
Chitosan (Cs) films are attractive for sustainable packaging due to biodegradability and intrinsic antimicrobial activity, yet their barrier and mechanical performances are often insufficient for demanding applications. Here, we report a two-step strategy combining covalent phenylurea grafting on chitosan (Cs-PU) with the incorporation of a Viburnum tinus L. fruit ethanolic extract (VTE) as a natural, pH-responsive indicator. Phenylurea grafting was designed to introduce strong, directional intermolecular interactions within the polymer matrix and led to marked improvements in film performance: compared with pristine Cs, Cs-PU showed ∼25 % higher tensile strength, a higher surface hydrophobicity (water contact angle: 81.8° → 101.2°), and a lower water vapor permeability (3.5 → 2.6 × 10⁻¹¹ g·m⁻¹·s⁻¹·Pa⁻¹). VTE, not previously reported as an additive for biopolymer film modification, endowed the films with pH-responsive optical functionality, producing a clear and reversible color shift over pH 0–14, while maintaining good structural and barrier properties. As a proof-of-concept application, Cs-PU@VTE films were used as headspace indicator labels for Atlantic cod (Gadus morhua): the labels exhibited rapid and sensitive colorimetric responses to spoilage-related volatile amines, with visible changes within 24 h at room temperature, enabling real-time freshness monitoring. Overall, this work demonstrates an integrated approach to obtain bio-based films that combine improved mechanical/barrier properties with smart colorimetric functionality for potential packaging applications.
On the structural, photophysical and antimicrobial properties of bimetallic Re-Fe coordination compounds bearing diimines ligands
Emilia R. Serrano, Pedro M. David Gara, Juan J. Martínez Medina, Filippo Prencipe, Oscar E. Piro, Gustavo A. Echeverría, Gabriela Petroselli, Tatiana Da Ros, Gustavo T. Ruiz
Published online: 8 December 2025
A new complex fac-[(ferroceneCO2)ReI(CO)3(dppz)] (dppz = dipyrido[3,2-a:2′,3′-c]phenazine) was obtained and fully characterized by elemental analysis, 1H and 13C NMR, ESI-mass, IR and UV–vis spectroscopy. We also report new insights into the structural and photophysical properties of the fac-[(ferroceneCO2)ReI(CO)3L], where L = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen), parent complexes. For all complexes, our results showed that: (i) no singlet oxygen generation was detected in acetonitrile solutions and (ii) they exhibited a very low luminescence quantum yield. However, photoacoustic measurements showed that under photoexcitation the complexes released all the absorbed energy to the medium as prompt heat. The antimicrobial activity of the ferroceneCO2-Re(CO)3(phen) complex was detected against both bacteria from American Type Culture Collections (ATCC) and clinically isolated bacterial strains. Antibacterial activity was rationalized in relation to extension of the π-system of the diamine ligands. Additionally, the ferroceneCO2-Re(CO)3(phen) complex showed no mutagenic potential.
Enhancement of mechanical and optical properties of modified chitosan films via grafting of multiple hydrogen bonding motifs
Mouad El Mouzahim, Alessandro Pedrini, Enrico Dalcanale, A. Jorge Parola and Roberta Pinalli
Published online: 19 November 2025
This study explores enhancing chitosan film (Cs) properties via supramolecular H-bonding cross-linking. The first unit, (1-(7-oxo-7,8-dihydro-1,8-naphtiridin-2-yl)urea (ODIN), was selected for its ability to self-dimerize via a sextuple H-bonding motif, while the second unit, phenyl urea (PU), was chosen as non-dimerizing unit that is still capable of forming extensive H-bonds. FTIR analysis confirmed the successful incorporation of ODIN and PU into the chitosan skeleton. The mechanical and barrier properties, and UV protection performances of the two modified polymers were determined and compared with those of pristine chitosan. These modifications resulted in enhanced surface hydrophobicity, and a substantial decrease in water vapor permeability. Mechanical testing revealed substantial reinforcement, with tensile strength increasing by up to 200 % for ODIN-modified films and up to 100 % for PU-modified ones. The UV-blocking performance of Cs-ODIN films was notably enhanced, providing complete protection across UVA, UVB, and UVC wavelengths, achieving a UPF of 161.95. The UV protective effect was further validated using the red cabbage test, which proved that Cs-ODIN films markedly reduced color degradation under UV exposure. Overall, this study shows that while PU mainly enhances barrier properties and mechanical performance through additional hydrogen-bonding interactions, ODIN not only provides similar improvements but also offers further benefits, including (i) enhanced UV-shielding and (ii) superior toughness and thermal stability driven by supramolecular dimerization.
Electrochemical catalysts for nitrogen reduction: progress, challenges, and sustainable solutions
Pramod Jadhav, Prakash Bhuyar, Abu Hasnat Mustafa, Izan Izwan Misnon, Mohd Hasbi Ab Rahim, Rasidi Roslan
Published online: 10 September 2025
Electrochemical nitrogen reduction (NR) is a promising pathway for sustainable ammonia (NH3) production, crucial for reducing reliance on fossil fuels and mitigating climate change. Various methods and advanced materials have been used to accelerate the NR reaction rate. However, the long-term sustainability and economic feasibility of many catalytic materials remain insufficiently studied. This review examines the roles of various catalysts, including metal-based, homogeneous, and heterogeneous catalysts, in facilitating NR reactions. The integration of advanced materials, such as metal–organic frameworks (MOFs) and photocatalytic nanoparticles, is discussed for their potential to enhance catalytic efficiency. The review highlights the importance of life cycle assessment (LCA) and techno-economic analysis (TEA) in evaluating the environmental and economic feasibility of NR processes. It also addresses the challenges and opportunities associated with green synthesis methods and large-scale application of MOFs. Future directions emphasise the need for interdisciplinary research, artificial intelligence (AI) advancements, and innovative energy storage solutions. This comprehensive analysis aims to guide the development of efficient, scalable, and sustainable NR technologies for a carbon–neutral future.
Dynamically crosslinked polyethylene-like materials with reversible self-reporting properties
Alessandro Torri, Chiara Paravidino, Gabriele Giovanardi, Francesco Rispoli, Fabrizio Moroni, Alessandro Pedrini, Enrico Dalcanale, Alberto Fina and Roberta Pinalli
Published online: 21 March 2025
In alignment with circular economy principles, we have developed a reprocessable, self-reporting thermoset based on polyethylene. The self-reporting feature is achieved using a mechanophore as the crosslinking agent, which reversibly responds to applied stress while being quenched by thermal stimuli. This same heat trigger also facilitates the material’s self-healing capability, ensuring efficient recovery and reusability. The chosen mechanophore is rhodamine, a widely recognized fluorescent dye known for its excellent stability, high absorption coefficient, and long-wavelength absorption and emission. For the covalent reversible bonds, we employ silylether exchange chemistry, as it enables the incorporation of crosslinker units without necessitating modifications to the polymer backbone.
Boronate Esters Dynamic Networks for the Reduction of Mechanical Anisotropy in Vat 3D Printed Manufacts
Alex Bonacini, Elena Saccani, Corrado Sciancalepore, Daniel Milanese, Gabriele Drago, Alessandro Pedrini, Roberta Pinalli, Renaud Nicolaÿ, and Enrico Dalcanale
Published online: 11 February 2025
Vat photopolymerization (VP) is a prominent 3D printing technique known for its high resolution and precision. However, mechanical anisotropy can limit the performance of printed structures by making their mechanical properties dependent on the printing orientation and curing conditions. This study introduces a photocurable material for VP 3D printing, combining dynamic boronate ester-based cross-linking with nondynamic cross-links. The material is synthesized using photoinduced free radical polymerization of a (meth)acrylate-based formulation, incorporating a diboronate ester with two methacrylate functionalities (DBEDMA) and a commercial poly(propylene glycol) diacrylate (PPGDA). The resulting resins exhibit rapid curing kinetics, low shrinkage (5–8%), and tailored viscoelastic properties. Stress relaxation and creep recovery studies highlight the role of boronate ester metathesis in enabling network rearrangement and stress dissipation. The optimal formulation, 40D60P, shows a significant reduction in mechanical anisotropy compared to an equivalent conventional resin containing only static cross-links (40B60P). Tensile tests confirm higher toughness and more consistent stress–strain behavior across printing orientations, attributed to partial topological rearrangement enabled by the dynamic cross-links. While improvements in isotropy are evident, a certain degree of mechanical anisotropy remains under specific conditions due to the presence of static cross-linking. Surface analysis via optical microscopy reveals smoother patterns in dynamic resin specimens, corroborating mechanical findings. This work demonstrates the potential of boronate ester-based dynamic chemistry to enhance the performance of VP 3D-printed materials, particularly in applications where reduced anisotropy and improved mechanical properties are critical.
Effect of silica nanoshell on the stability and thermochromic properties of monoclinic VO2 particles dispersed in Poly(vinylbutyral) films
María de la Paz Miguel, María Jazmín Penelas, Gustavo Francisco Arenas, Cristina Elena Hoppe, Rodrigo Parra, Julieta Puig
Published online: 7 February 2025
Belt-shaped particles of the metastable phase vanadium dioxide (VO2(B)) were synthesized via a hydrothermal method using ammonium metavanadate and oxalic acid. To be transformed into the thermochromic monoclinic phase (VO2(M)), the particles were annealed at 550°C. To enhance the stability and optical properties while preventing coarsening, a SiO2 nanoshell was grown on the VO2(B) particles using a modified Stöber method. This SiO2 shell protected the particles, preserving their morphology and preventing coarsening. The resulting VO2(M) particles were incorporated into composite films made from PVB, a UV-resistant polymer used in security glass. These films demonstrated excellent transparency and contrast between transmissive and reflective states, attributed to the SiO2 shell’s stabilizing effects. The SiO2-coated before the annealing treatment VO2 particles also exhibited improved chemical and thermal stability. These findings show the potentiality of SiO2-coated VO2(M), as a material to produce laminated protective glass with long-term thermochromic properties.
One-pot catalytic conversion of cellulose biomass to bioethanol at low pressure and temperature conditions: H2O as a self-hydrolytic agent
Venkata Rao Madduluri, Siti Khadijah Mazran, Anisah Sajidah Saud, Gaanty Pragas Maniam, Rasidi Roslan, Mohd Hasbi Ab Rahim
Published online: 25 October 2024
The development of sustainable protocols for the synthesis of bioethanol from cellulose biomass using reduction-free heterogenous catalysts without external H2 is a challenging task. In this work, a highly active and robust Ni-Pd/iron oxide catalyst has been reported for the synthesis of bioethanol from microcrystalline cellulose (MCC) in a single-step, one-pot process using H2O as a green solvent. The catalysts were synthesized by facile and scalable co-precipitation and wet-impregnation methods. H2O functions as a hydrolytic agent, and Ni-Pd composites play the role of the hydrogenolysis/hydrogenation active sites. The different catalytic profiles were obtained over wet-impregnated and co-precipitated catalysts by altering the temperatures and pressure conditions, respectively. The wet-impregnated Pd-Ni/iron oxide catalyst provided improved catalytic activity due to uniformly distributed active metal particles observed from FE-SEM analysis, optimum crystalline size, particle size, and high surface area. In addition, the spent catalyst was tested and proven to be reusable with comparable bioethanol yields and greater cellulose conversion under optimized experimental conditions. In brief, the finding further expands the possible valorization of any cellulosic-based biomass into a high-value bioethanol chemical and fuel.
Recent Advances in Vitrimers: A Detailed Study on the Synthesis, Properties and Applications of Bio-Vitrimers
Venkata Rao Madduluri, Anjaneyulu Bendi, Chinmay, Gaanty Pragas Maniam, Rasidi Roslan, Mohd Hasbi Ab Rahim
Published online: 10 October 2024
Nowadays, thermoset polymers stand out as notable composites, but the surge in global thermoplastic production has raised concerns due to the non-recyclability of these composites, leading to an increase in landfill waste. In response to these challenges, researchers are investigating innovative approaches to enhance thermosetting materials, focusing on the modification of crosslinking agents responsible for forming a covalently bonded network. Vitrimers offer a promising solution by enabling re-processability while maintaining favourable thermo mechanical properties and solvent resistance. Although many current vitrimers use synthetic polymeric molecules from fossil-based sources, there is a growing interest in bio-based vitrimers. While still in early development, these bio-based alternatives leverage biomass for creating durable polymers, aligning with the goal of establishing a circular economy. This review has been designed to highlight the use of covalently modified networks to produce advanced synthetic and bio-based vitrimer composites with diverse applications, contributing to the development of sustainable materials for the next generation through the use of recyclable resources and renewable feedstocks in polymer network synthesis. This review also explores vitrimers, examining their unique characteristics and addressing current limitations hindering their widespread adoption as recyclable materials with superior performance.
Advancement of lignin into bioactive compounds through selective organic synthesis methods
Pramod Jadhav, Prakash Bhuyar, Izan Izwan Misnon, Mohd Hasbi Ab Rahim, Rasidi Roslan
Published online: 21 July 2024
The conversion of lignin into bioactive compounds through selective organic synthesis methods represents a promising frontier in the pursuit of sustainable raw materials and green chemistry. This review explores the versatility of lignin-derived bioactive compounds, ranging from their application in drug discovery to their role in the development of biodegradable materials. Despite notable advancements, the synthesis routes and yields of highly bioactive molecules from lignin still require further exploration and improvement. This review provides an in-depth examination of the progress made in understanding the complex structure of lignin and developing innovative approaches to exploit its potential. Specifically, the types of lignins covered include softwood Kraft lignin, hardwood organosolv lignin, and soda lignin. This work is divided into three parts: first, the transformation of lignin into bioactive molecules with chemically active centres and functionalised hydroxyl groups through depolymerisation; second, kinetic modelling techniques essential for understanding the chemical kinetics of lignin and enabling significant scaling up in the conversion of organic molecules; third, efficient catalytic pathways for synthesising molecules with anticancer and antibacterial properties. In conclusion, this comprehensive review spurs further investigations into lignin-derived bioactive compounds, their applications, and the advancement of sustainable processes.
On-Surface Molecular Recognition Driven by Chalcogen Bonding
Luca Camilli, Conor Hogan, Deborah Romito, Luca Persichetti, Antonio Caporale, Maurizia Palummo, Marco Di Giovannantonio, Davide Bonifazi
Published online: 5 June 2024
Chalcogen bonding interactions (ChBIs) have been widely employed to create ordered noncovalent assemblies in solids and liquids. Yet, their ability to engineer molecular self-assembly on surfaces has not been demonstrated. Here, we report the first demonstration of on-surface molecular recognition solely governed by ChBIs. Scanning tunneling microscopy and ab initio calculations reveal that a pyrenyl derivative can undergo noncovalent chiral dimerization on the Au(111) surface through double Ch···N interactions involving Te- or Se-containing chalcogenazolo pyridine motifs. In contrast, reference chalcogenazole counterparts lacking the pyridyl moiety fail to form regular self-assemblies on Au, resulting in disordered assemblies.
Alternative Concepts for Extruded Power Cable Insulation: from Thermosets to Thermoplastics
Amir Masoud Pourrahimi, Massimiliano Mauri, Silvia D'Auria, Roberta Pinalli, Christian Müller
Published online: 12 April 2024
The most common type of insulation of extruded high-voltage power cables is composed of low-density polyethylene (LDPE), which must be crosslinked to adjust its thermomechanical properties. A major drawback is the need for hazardous curing agents and the release of harmful curing byproducts during cable production, while the thermoset nature complicates reprocessing of the insulation material. This perspective explores recent progress in the development of alternative concepts that allow to avoid byproducts through either click chemistry type curing of polyethylene-based copolymers or the use of polyolefin blends or copolymers, which entirely removes the need for crosslinking. Moreover, polypropylene-based thermoplastic formulations enable the design of insulation materials that can withstand higher cable operating temperatures and facilitate reprocessing by remelting once the cable reaches the end of its lifetime. Finally, polyethylene-based covalent and non-covalent adaptable networks are explored, which may allow to combine the advantages of thermoset and thermoplastic insulation materials in terms of thermomechanical properties and reprocessability.
Polyethylene ionomers as thermally reversible and aging resilient adhesives
Silvia D'Auria, Peter Neuteboom, Roberta Pinalli, Enrico Dalcanale, Jérôme Vachon
Published online: 03 April 2024
In this work, we report the effect of the reaction conditions on IPC content and melt flow index (MFI) for the PE ionomer obtained by copolymerizing ethylene with the ion pair dimethyl-amino methacrylate and methacrylic acid. The resulting ionomers exhibited improved mechanical properties, including higher elongation and stress at break, making them superior to conventional LDPE. The developed ionomers display enhanced adhesion properties on aluminum substrates with respect to LDPE. Remarkably, the adhesives exhibit thermal reversibility, making them suitable for applications requiring disassembly. Accelerated aging tests demonstrate the ionomers’ durability, with some even showing increased adhesion after exposure to harsh conditions. Overall, this study highlights the potential of PE-based ionomers as advanced materials that combine the benefits of thermosets and thermoplastics, while offering outstanding adhesive properties when the IPC content is higher than 1 mol %.
Synthesis and
Processing of Near Infrared—Activated Vitrimer Nanocomposite Films
Modified with β-Hydroxyester-Functionalized Multi-Walled Carbon
Nanotubes
Synthesis and Processing of Near Infrared—Activated Vitrimer Nanocomposite Films Modified with β-Hydroxyester-Functionalized Multi-Walled Carbon Nanotubes
Tomás E. Byrne Prudente, Diandra Mauro, Julieta Puig, Facundo I. Altuna, Tatiana Da Ros and Cristina E. Hoppe
Published online: 08 December 2023
Films of a vitrimer based on the reaction between diglycidylether of bisphenol A and glutaric acid in the presence of 1-methylimidazole were processed using a solvent-based technique. The curing schedule was divided into two steps: first, a soluble linear polymer was formed through the reaction of the diacid and the diepoxide, and then the crosslinking was induced at a higher temperature via transesterification reactions. This epoxy–acid vitrimer was modified with multi-walled carbon nanotubes (MWCNTs) functionalized with β-hydroxyesters, produced by a robust and straightforward strategy based on a two-phase reaction between oxidized MWCNTs and phenylglycidylether. Nanocomposite vitrimer films were obtained by drop casting a dispersion of the functionalized MWCNTs in the linear polymer/cyclohexanone solution, followed by a thermal treatment. A high degree of dispersion of the carbon nanostructures was attained thanks to the β-hydroxyester functionalization when compared with oxidized MWCNTs. Nanocomposite films showed a significant photothermal effect (reaching 200 °C or above in 30 s) upon NIR light irradiation (850 nm) from a single LED (500 mW/cm2). The released heat was used to activate the shape memory effect and weld and heal the vitrimer matrix, proving the success of this easy strategy for the generation of remotely activated carbon-based vitrimer nanocomposites.
CIE color coordinates for the design of luminescent glass materials
CIE color coordinates for the design of luminescent glass materials
Andreia Ruivo and César Laia
Published online: 08 November 2023
In this study, a soda-lime silicate glass composition was doped with a mixture of different lanthanide oxides to increase the luminescence color palette. The same glass sample can also present different colors by changing the excitation light, allowing higher tunability of luminescent colors. It was effectively demonstrated the extensive spectrum of colors produced, which was represented through luminescence color coordinates for all synthesized glasses. Moreover, the possibility of detecting if an excited state process is occurring was studied by calculating the lanthanides factors and comparing them with those used in the glass synthesis. Nevertheless, it is shown that the energy transfer process has to be significant to influence the color coordinates and the calculation of the factors.
Photoreduction of Anthracenes Catalyzed by peri-
Xanthenoxanthene: a Scalable and Sustainable Birch-Type
Alternative
Cristian De Luca, Davide Zanetti, Tommaso Battisti, Rúben R. Ferreira, Sofia Lopez, Alexander H. McMillan, Sasha Cai Lesher-Pérez, Laura Maggini, and Davide Bonifazi
Published online: 18 August 2023
Photocatalyzed “Birch-type” reduction of acenes by using peri-xanthenoxanthene (PXX). This work presents a novel method for reducing various full-carbon acenes using visible blue light and PXX as a photocatalyst. By attaching PXX to PDMS beads, catalyst recyclability can be achieved without compromising efficiency. Integration of the PXX-PDMS beads into a microreactor enabled the reduction of acenes under continuous-flow conditions, thereby validating the sustainability and scalability of this heterogeneous-phase approach.
Phenoxy Resin-Based Vinylogous Urethane Covalent Adaptable Networks
Giuseppe Soavi, Francesca Portone, Daniele Battegazzore, Chiara Paravidino, Rossella Arrigo, Alessandro Pedrini, Roberta Pinalli, Alberto Fina, Enrico Dalcanale
Published online: 30 July 2023
This work presents a post-polymerization approach to the preparation of vitrimers, exploiting the transamination of vinylogous urethane in linear phenoxy resins. The conversion of linear polymers to dynamic crosslinked networks is confirmed by dynamic mechanical thermal analyzer and rheology measurements, followed by stress relaxation tests to investigate the kinetics of bond exchanges. Tensile tests as a function of reprocessing cycles reveal an increase of the maximum elongation and stress at break and prove the good recyclability of the vitrimers. Enhanced adhesive properties compared to pristine phenoxy resins are demonstrated, including the possibility to thermally re-join the assembly after its mechanical failure. Finally, the solvent-free preparation of vitrimers is explored at 5% crosslinking density via melt reactive blending, providing a valuable alternative to the less environmentally sustainable synthesis in solution.
Polyethylene Based Ionomers as High Voltage Insulation Materials
Silvia D'Auria, Amir Masoud Pourrahimi, Alessia Favero, Peter Neuteboom, Xiangdong Xu, Shuichi Haraguchi, Marko Bek, Roland Kádár, Enrico Dalcanale, Roberta Pinalli, Christian Müller, Jérôme Vachon
Published online: 30 May 2023
Polyethylene based ionomers are found to be a promising high-voltage insulation material. The synthesized ionomers behave as cross-linked materials with a rubber plateau above the melting temperature and a low direct-current electrical conductivity of 2 to 6·10−14 S m−1 at 70 °C and an electric field of 30 kV mm−1, which is comparable to cross-linked polyethylene, the most widely used insulation material for extruded high-voltage direct-current (HVDC) cables.
New organic platform to integrated photonic device
fabrication
Gustavo Torchia, Cristina Hoppe, César Laia, Jorge Parola and Ginés Lifante-Pedrola
Published online: 15 May 2023
This paper presents a new technological platform for the development of integrated optical circuits for applications in photonics. It is based on supramolecular polymeric materials whose behaviour resembles that of those known as vitrimers. These were synthesized by reaction between diglycidyl ether of bisphenol A (DGEBA) and different n-alkylamines. The photonic characteristics of thin films made from these polymeric systems using the spin coating technique on commercial glass substrates are presented. The reflectivity curves of coupled laser light in the films through a high refractive index prism are also shown and analysed. From these results, thin films show guided modes
in both polarizations (TE-TM) for electromagnetic radiation in the UV-visible range. Likewise, from the experimental data, the refractive index and thickness of the explored films are determined.
2D material hybrid heterostructures: achievements and challenges towards high throughput fabrication
Laura Maggini and Rúben R. Ferreira
Published online: 11 October 2021
2D materials have attracted tremendous attention since the discovery of graphene, because of their unique optical/electronic/mechanical properties, and their manipulable bidimensional morphology. Since forthcoming technologies require a stringent yet faceted portfolio of features, hardly feasible using a single pristine material, the demand for property tuning and multifunctionality has led to the development of hybrid 2D material heterostructures to modulate and exploit the synergy between two or more materials and achieve novel properties. Because of their straightforwardness in implementation and rich variety of possible combinations, these hybrid architectures, held together mostly by non-covalent interactions, virtually allow the fabrication of any kind of assembly offering a unique opportunity for fine-tuning the properties of materials. However, reproducibility, scale-up, assembly into ordered structures and processability are the challenges yet to be addressed to technologically harness their full potential, and enable their integration into mass produced commercial devices. In this perspective article we analyse the recent developments in the automatised production of hybrid solution processed 2D material heterostructures, especially emphasising on the technologies that are currently closer to achieving low-cost, high-throughput standardised production, namely spray coating, inkjet printing and 3D printing, to sense the direction this research field is taking in pursuit of the development of commercialisable products.
