The Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET-ATRP) of vanillin methacrylate (VMA), a bio-based methacrylic monomer derived from vanillin, was systematically studied for the first time. The reaction conditions were optimized aiming at achieving good monomer conversions while preserving the antimicrobial aldehyde functionality. Bipyridine-based catalysts showed limited effectiveness, whereas polydentate aliphatic amines displayed higher activity. Kinetic studies showed linear profiles during the early stages of the polymerization before reaching a conversion plateau accountable to the depletion of the reducing agent, as confirmed by reactivation experiments. The resulting polymer (PVMA) exhibited a glass transition temperature comparable to that of poly(styrene), emerging as a potential bio-derived alternative to fossil-based thermoplastic materials. Furthermore, preliminary in vitro tests demonstrated that PVMA has potential antimicrobial activity against both Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive).

The combined elasticity, processability, and recyclability of thermoplastic elastomers (TPEs) has enabled their widespread adoption across diverse industrial sectors. In particular, TPEs have emerged as attractive alternatives to chemically crosslinked elastomers, contributing to extended product lifetimes and reduced waste generation. Their performance arises from the presence of physical, reversible crosslinks, which allow the integration of elastomeric behaviour with thermoplastic reprocessability. This review provides an overview of recent advances in ABA thermoplastic elastomer (TPE) design, focusing on three major classes: styrenic block copolymers, acrylic-based TPEs, and emerging bio-based systems, with particular emphasis on the latter. Special attention is given to structure-property relationships and the influence of molecular architecture on thermomechanical behaviour. Styrenic block copolymers remain the most established class, offering well-defined phase-separated morphologies and tuneable mechanical properties. Acrylic-based TPEs have attracted increasing interest owing to their superior thermal and oxidative stability and versatile molecular design. We also discuss recent progress in bio-based TPEs derived from renewable resources, which aim to reduce reliance on fossil feedstocks without compromising performance. Finally, we examine current challenges and future perspectives, highlighting the need for sustainable synthetic strategies and advanced TPEs with lower environmental impact.

The accumulation of micro- and nano-plastics (MNPs) in terrestrial ecosystems poses an emerging threat to soil health and plant development. This study examined the effects of fluorescent polystyrene MNPs (0.1-100µm; 0.01-1gL-1) with heterogeneous sizes and shapes on soil properties, microbial activity, and the morpho-physiological traits of Arabidopsis thaliana. In parallel, we assessed whether biochar (20% v/v) could mitigate MNPs-induced alterations. MNPs contamination decreased the soil cation exchange capacity and modified micronutrient availability without affecting pH, whereas biochar significantly increased pH, carbon, and nutrient content. In control soils, higher MNPs concentrations delayed germination and reduced shoot biomass and rosette area, while biochar-amended soils maintained stable or enhanced plant growth and root development across all contamination levels. MNPs exposure induced oxidative stress in roots, with increased hydrogen peroxide and superoxide radical accumulation, but did not upregulate the expression of three root peroxidase genes. Biochar improved microbial biomass and basal respiration, although its combination with MNPs resulted in complex and enzyme-specific responses. Overall, biochar ameliorated several adverse effects of MNPs contamination by enhancing soil fertility and plant performance, suggesting its potential as a sustainable soil amendment to mitigate plastic pollution in terrestrial environments.

Polyesters (PEs) are among the most important classes of plastics. The identification of new, biobased, and renewable sources is necessary to increase the sustainability of PEs and related materials production. Herein, we describe the synthesis of three epoxy monomers derived from 4-vinylguaiacol, a functional molecule easily obtained from biobased ferulic acid. These monomers, namely 4-epoxyguaiacol acetate, butanoate, and hexanoate, were used in ring-opening copolymerization reactions in combination with different cyclic anhydrides, promoted by simple, (organo)catalytic initiators [i.e., bis-(triphenylphosphine)iminium chloride, tetrabutylammonium bromide, 4-(dimethylamino)pyridine, and cesium acetate]. Reactions were carried out with and without solvents, allowing the synthesis of 12 new and structurally different PEs containing up to 100% renewable monomers. The obtained PEs have number-average molecular weights (Mn) in the range of 1.8-4.1 kDa, and dispersity indexes (Đ) in the range of 1.09-1.62. Only for maleic anhydride, higher Mn and Đ values were observed, likely due to side reactions involving the double bond on the anhydride backbone. Thermal analyses revealed that, depending on the PE structure, glass transition temperatures can be modulated between 0 and 78 °C, while mass analyses confirmed the presence of hydroxy-terminated polymer chains, supporting their application as low molecular-weight polyester polyols.

In this work, fully biobased acrylic ABA triblock copolymers were synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization using VISIOMER (R) Terra C13 (ET13) as the "soft" midblock and two terpenoid-derived methacrylates, betulin methacrylate (BetuMA) and carvacryl methacrylate (CaMA), as the glassy blocks. An "R-linked" bifunctional chain transfer agent (bis-CTA) enabled the formation of ET13 macro-CTAs with controlled molecular weights and narrow dispersity (M-n = 84-229 kg mol(-1), & Dstrok; approximate to 1.1). RAFT homo-polymerizations of BetuMA and CaMA yielded well-defined homopolymers (M-n = 20-33 kg mol(-1), & Dstrok; < 1.4) with selective methacrylate reactivity. Chain extension of ET13 macro-CTAs produced a series of ABA triblocks featuring 8-39 mol% glassy content. GPC confirmed molecular weights in the range M-n = 97-415 kg mol(-1) (& Dstrok; < 1.7), while DSC and TGA analyses showed distinct glass transitions for soft block, close to -50 degrees C, and good thermal stability. AFM evidenced clear microphase separation. Mechanical testing revealed that BetuMA-based copolymers (BEB series) achieved tensile strengths up to 3.9 MPa and elongations up to 760%, outperforming CaMA-based analogs (CEC series: sigma <= 1.2 MPa, epsilon <= 710%). These results demonstrate the efficacy of RAFT polymerization of terpenoid methacrylates in producing high-performance, sustainable thermoplastic elastomers, offering a viable alternative to petroleum-derived thermoplastic elastomers (TPEs).

Herein we report on a kinetic study of Cu-based catalysts employed in the ARGET-ATRP of the methacrylic derivative of eugenol, namely eugenyl methacrylate (EuMA). Polymerizations were carried out in solution in presence of catalytic systems formed in situ by CuBr2 and nitrogen-ligands such as BiPy, PMDETA, HMTETA and Me6TREN. The formation of insoluble polymers, due to secondary reactions responsible of cross-linking, was observed with CuBr2/BiPy and CuBr2/HMTETA systems; Me6TREN- and PMDETA-based catalyst proved, instead, to be capable of generating linear polymers. For the latter, first order kinetics occurred for monomer conversion up to ca 50 %, whilst higher conversion led to deviations from the linear trend. This suggested the direct involvement of the allyl group in the termination reactions, which was convincedly demonstrated by comparing kinetic results for EuMA and the corresponding di-hydrogenated monomer (DEuMA). At EuMA conversion above 50 %, the side reactions lead to inactivation of the PMDETA-based catalytic system via reducing agent consumption rather than to the formation of insoluble/crosslinked polymers. Electronic structure calculations provided the energy profile for all possible side reactions. Among these, the radical chain transfer to the allyl group through hydrogen abstraction, as well as the attack of the propagating methacrylic radical to the allyl group, contributed to rationalizing the experimental behavior of the three copper-catalyst systems employed in this work. This study demonstrates that modulating the kinetic of polymerization by properly selecting ligands and reaction temperatures represents a useful strategy towards the reduction of undesired secondary reactions of molecules with sensitive functional groups such as bio-derived phenols; moreover, such preserved functional groups would serve as possible post-functionalization sites (i.e. epoxidation) allowing for the preparation of new materials with tailored properties.

This review reports an up-to-date overview of the synthetic methodologies developed for the preparation of large cyclic organic carbonates with ≥6-membered rings (6M-CCs and above), highlighting the most sustainable synthetic pathways employing diols (including renewable-based ones) and nonhazardous carbonyl sources, e.g., linear organic carbonates, in mild operating conditions. The lower thermodynamic stability of 6M-CCs compared to 5-membered ones allows for a straightforward preparation of biocompatible aliphatic polycarbonates (APCs), occurring via ring-opening polymerization (ROP), in the presence of various active organo- and/or biocatalysts. Moreover, ROP processes can be tuned for the selective preparation of copolymers with different thermomechanical properties and can be further applied to structurally complex, larger cyclic carbonate derivatives. Finally, the end-of-life fate of APCs, particularly the recently reported controlled depolymerization strategies, is critically discussed focusing on chemoselectivity toward cyclic carbonate or epoxide monomers. This timely overview highlights the open challenges as well as the opportunities associated with the synthesis of APCs and chemical recycling and highlights their potential as circular and sustainable plastics.

Plastic pollution represents a persistent global issue, with catastrophic effects on ecosystems. Due to unique properties, these synthetic materials do not break down into biodegradable compounds when naturally dispersed, but degrade into smaller fragments, known as micro- (MPs) and nanoplastics (NPs), that easily enter the food chain. Among plastics, polypropylene (PP) is one of the most common, whose consumption has dramatically increased in recent years for single-use packaging and surgical masks. In this context, given the widespread detection of PP-MPs and NPs in various biological matrices, investigating their toxicity in living organisms is crucial. For these reasons, this study aims to assess how PP-MPs and NPs affect tissue regeneration following injury, proposing the freshwater leech Hirudo verbana as an established experimental model. Injured leeches were examined at different time points after plastic administration, and analyses were conducted using microscopy, immunofluorescence, and molecular biology techniques. The results demonstrate that plastic exposure induces fibrosis, disrupts tissue reorganization, delays wound repair, and activates the innate immune and oxidative stress responses. In summary, this project provides new insight into the adverse effects of PP particles on living organisms, highlighting for the first time their negative impact on proper tissue regeneration.

Synthetic polymer surfaces provide an excellent opportunity for developing materials with inherent antimicrobial and/or biocidal activity, therefore representing an answer to the increasing demand for antimicrobial active medical devices. So far, biologists and material scientists have identified a few features of bacterial cells that can be strategically exploited to make polymers inherently antimicrobial. One of these is represented by the introduction of cationic charges that act by killing or deactivating bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). Among the possible cationic functionalities, the antimicrobial activity of polymers with quaternary ammonium centers (QACs) has been widely used for both soluble macromolecules and non-soluble materials. Unfortunately, most information is still unknown on the biological mechanism of action of QACs, a fundamental requirement for designing polymers with higher antimicrobial efficiency and possibly very low toxicity. This mini-review focuses on surfaces based on synthetic polymers with inherently antimicrobial activity due to QACs. It will discuss their synthesis, their antimicrobial activity, and studies carried out so far on their mechanism of action.

Star copolymer films were produced by using spin-coating, drop-casting, and casting deposition techniques, thus obtaining ultrathin and thick films, respectively. The morphology is generally flat, but it becomes substrate-dependent for ultrathin films where the planarization effect of films is not efficient. The indentation hardness of films was investigated by Force Volume Maps in both the air and liquid. In the air, ultrathin films are in the substrate-dominated zone and, thus, the elastic modulus E is overestimated, while E reaches its bulk value for drop-casted ultrathin and thick films. In liquid (water), E follows an exponential decay for all films with a minimum soaked time t0 of 0.37 and 2.65 h for ultrathin and drop-casted ultrathin and thick films, respectively. After this time, E saturates to a value on average 92% smaller than that measured in the air due to film swelling. Such results support the role of film morphology in the antimicrobial activity envisaged in the literature, suggesting also an additional role of film hardness.

Production of the high industrial value cis,cis-muconic acid (ccMA) from renewable biomasses is of main interest especially when biological (green) processes are used. We recently generated a E. coli strain expressing five recombinant enzymes to convert vanillin (VA, from lignin) into ccMA. Here, we optimized a growing cell approach in bioreactor for the ccMA production. The medium composition, fermentation conditions, and VA addition were tuned: pulse-feeding VA at 1 mmol/h allowed to reach 5.2 g/L of ccMA in 48 h (0.86 g ccMA/g VA), with a productivity 4-fold higher compared to the resting cells approach, thus resulting in significantly lower E-factor and Process Mass Intensity green metric parameters. The recovered ccMA has been used as building block to produce a fully bioderived polymer with rubber-like properties. The sustainable optimized bioprocess can be considered an integrated approach to develop a platform for bio-based polymers production from renewable feedstocks.

Synthetic polymer surfaces provide an excellent opportunity for developing materials with inherent antimicrobial and/or biocidal activity, therefore representing an answer to the increasing demand for antimicrobial active medical devices. So far, biologists and material scientists have identified a few features of bacterial cells that can be strategically exploited to make polymers inherently antimicrobial. One of these is represented by the introduction of cationic charges that act by killing or deactivating bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). Among the possible cationic functionalities, the antimicrobial activity of polymers with quaternary ammonium centers (QACs) has been widely used for both soluble macromolecules and non-soluble materials. Unfortunately, most information is still unknown on the biological mechanism of action of QACs, a fundamental requirement for designing polymers with higher antimicrobial efficiency and possibly very low toxicity. This mini-review focuses on surfaces based on synthetic polymers with inherently antimicrobial activity due to QACs. It will discuss their synthesis, their antimicrobial activity, and studies carried out so far on their mechanism of action.

The increasingly intense consumption of plastics and, above all, their improper disposal in the environment are causing serious environmental concerns. Great efforts have been made for the development of new methods aimed at facilitating and speeding up the identification and sorting of different materials in the plastic recycling process. In this field, new strategies based on fluorescent tagging have been developed. This work concerns the synthesis and characterization of new fluorescent copolymers of polyethylene (PE) and polystyrene (PS), which are among the most produced and consumed plastic materials. The synthesized copolymers are potentially suitable for use as fluorescent markers of PE and PS. Ethylene-co-N-pentenyl carbazole (P(E-co-PK)) and styrene-co-4-(N-carbazolyl)methyl styrene (P(S-co-SK)) copolymers were prepared by Ziegler–Natta and free radical polymerization, respectively. If excited at 300 nm, both P(E-co-PK)s and P(S-co-SK)s give fluorescence emissions resulting in them being optically active. Moreover, due to the low amount of fluorescent units, they show chemico-physical properties such as those of their corresponding homopolymers (PE and PS). P(E-co-PK)s and P(S-co-SK)s have been also tested as fluorescent markers of PE and PS. The experimental results demonstrate that from PE/P(E-co-PK) and PS/P(S-co-SK) blends prepared using only 1% by weight of fluorescent copolymer, distinguishable fluorescent emissions can be still detected.

Hydrogen bonds between carboxylic groups of hydrophilic polyacids and anionic moieties in surfactant headgroups may reduce the critical concentration above which surfactants aggregate provided the interaction is sufficiently strong. As undissociated acid groups are needed, the reduction should depend on the solution pH and acid concentration. Pyrene fluorescence was employed to investigate the impact that polyacrylic acid has on the critical concentration of two sulfonate containing surfactants, sodium dodecylbenzene sulfonate and lauryl sulfobetaine, as a function of pH and polyacid concentration. Non-ionic Tween80 was instead used to gauge if polyacid hydrophobicity plays any role. Monte Carlo simulations were also run to better understand the impact of changing composition variables. No change in Tween80 critical concentration was detected, suggesting that polyacrylic acid hydrophobicity has a negligible impact on aggregation modalities. A marked reduction of the critical aggregation concentration of the ionic surfactants was instead measured titrating solutions containing 0.05 and 0.2% (w/w) of polyacrylic acid, its impact found to be pH and concentration dependent. Albeit qualitatively agreeing with experiments and rationalizing the lowering of sodium dodecylbenzene sulfonate critical concentration at high pH, Monte Carlo results indicated the need for a model re-parameterization.

In this work, two compounds belonging to the BODIPY family, and previously investigated for their photosensitizing properties, have been bound to the amino-pendant groups of three random copolymers, with different amounts of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the backbone. The P(MMA-ran-DMAEMA) copolymers have inherently bactericidal activity, due to the amino groups of DMAEMA and to the quaternized nitrogens bounded to BODIPY. Systems consisting of filter paper discs coated with copolymers conjugated to BODIPY were tested on two model microorganisms, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). On solid medium, irradiation with green light induced an antimicrobial effect, visible as a clear inhibition area around the coated disks. The system based on the copolymer with 43% DMAEMA and circa 0.70 wt/wt% of BODIPY was the most efficient in both bacterial species, and a selectivity for the Gram-positive model was observed, independently of the conjugated BODIPY. A residual antimicrobial activity was also observed after dark incubation, attributed to the inherently bactericidal properties of copolymers.

Plastics are a heterogeneous class of synthetic compounds that, due to their unique characteristics find numerous applications both in industrial and civil fields. However, despite the great advantages that these materials brought in everyday life, the plastic wastes resulting from their massive use represent one of the main environmental problems at the global level. Once released, plastics persist for a long time and are subjected both to biotic and abiotic processes leading to the formation of small particles, known as micro and to nanoplastics, that interact with organisms, accumulating inside tissues and risking to enter in the trophic chain. Among the different types of plastic, polypropylene (PP) is one of the diffused, widely exploited in food and textile industries for disposable packaging and to produce surgical masks. Owing to the huge distribution and the resultant abundant presence of PP waste products, it results necessary investigate the possible toxicity on living organisms. For these reasons, here we analyzed the effects of PP micro and nanoplastics dispersed in freshwater, using the medicinal leech Hirudo verbana as invertebrate model. To better follow the plastics fate, fluorescent particles, labeled with a fluorophore, have been used. Animals were examined at various timings after plastics exposure and results were analyzed by means of microscopy, immunofluorescent and molecular biology analyses. After assessing the entrance of PP fragments into leech tissues, the activation of the innate immune response was evaluated. The results show that the presence of micro and nanoplastics induces an initial physical protection that consists in the secretion of mucus, followed by an increase of blood vessels and the recruitment of immune cells, in particular macrophages. Moreover, macrophages were directly involved in both phagocytic and encapsulation processes, as demonstrated by acid phosphatase (ACP) histoenzymatic and Thioflavin-T assays, expressing specific pro-inflammatory factors, such as HvRNASET2 and HmAIF-1, as demonstrated by immunolocalization and qPCR experiments. Finally, the expression levels of genes related to oxidative stress-induced enzymes have been investigated, in order to evaluate the possible increase in reactive oxygen species (ROS), due to the entry into the leech tissues of PP micro and nanoplastics. This work allows deepening the current knowledge of the possible harmful effects on human health deriving from micro and nanoplastics dispersion, leading new insight about freshwater ecosystems that often represent the first environments interested in plastic pollution.

The adaptation of polymeric matrices to tailor their drug release characteristics requires the complete understanding of the mechanism involved. We thus explored how chemical and structural modifications of film forming polymethyl methacrylate (PMMA), a polymer often used for its biocompatibility, impact on its release features. Comparing Diclofenac Sodium (NaD) salt release from pure PMMA, mPEG-b-(PMMA)(n), and mPEG-b- (PMMA-ran-DMAEMA)n polymeric films (n = 1, 2), we evidenced the impact of successive polymer modifications on the release rate and equilibrium. Thus, PEGylation increased both the release rate and the amount of NaD desorbed (up to 53%) introducing, however, a "burst phase " not present with pure PMMA; the latter released only 3% of NaD. The presence of DMAEMA in mPEG-b-(PMMA-ran-DMAEMA)(n), instead, decreased the release rates and led to the complete NaD desorption at physiological conditions. We rationalized our observations with electronic structure calculations and lattice stochastic simulations. The former suggested a tendency for NaD to accumulate in the hydrophilic mPEG portion via the coordination of the sodium cation in low polarity casting solvents. Stochastic simulations, instead, suggested that mPEG ought to form small domains on the film surface favouring fast NaD desorption in the release medium. Importantly, DMAEMA reduced the NaD tendency to accumulate in the mPEG portion due to the coordination on MMA-DMAEMA motifs. In physiological conditions (i.e., pH +/- 6.4), the basic monomer also dampens the burst phase and reduces the release rate compared to the other matrices thanks to salt bridges between the drug and amino group.

Hypothesis: The critical concentration above which micelles form from zwitterionic surfactant solutions and their thermodynamic stability is affected by the interaction with weak Bronsted polyacid chains (A(n)) via the formation of charged hydrogen bonds between the latter and anionic moieties. Experiments: The interaction between zwitterionic micelles and polyacids capable of forming hydrogen bonds, and its dependence on the environmental pH and polymer structure, has been studied with constant-pH simulations and a restricted primitive model for all electrolytes. Findings: At low pH, the formation of polyacid/micelle complexes is witnessed independently of the poly-mer size or structure, so that the concentration above which micelles form is substantially decreased compared to polyacid-free cases. Upon rising pH, polymer desorption takes place within a narrow range of pH values, its location markedly depending on the size and structure of polyacids, and on the relative disposition between headgroup charged moieties. Thus, the desorption onset for long linear polyacids (A(60)) interacting with sulphobetainic headgroups is roughly two pH units higher than for six decameric chains (6A(10)) adsorbed onto micelles bearing phosphorylcholinic headgroups. This effect, together with the preferential desorption of chain ends at intermediate pH, may be exploited for drug delivery purposes or building advanced metamaterials. (C) 2021 Elsevier Inc. All rights reserved.

Hypothesis: The stronger motional coupling between monovalent counterions neutralizing homogeneously like-charged surfaces induced by an increase in charge density is known to foster inter-surface attraction. Compared to a uniformly distributed charge, point-like charges generate locally more intense fields, so that the correlation induced between counterions may be even stronger despite an identical total charge. It should thus be possible to induce surface attraction at lower charge densities than commonly expected. Experiments: Monte Carlo simulations on primitive electrolyte models have been exploited to compute potential of mean force profiles and mobile ion densities for systems composed of two parallel surfaces bearing surface-tethered monovalent like-charged pendants as a function of the surface distance and pendant densities. Findings: Surfaces bearing like-charged pendants are found to attract each other over a wide range of distances despite the presence of very low charge densities. Notwithstanding the attractive contribution to the inter-surface forces provided by electrostatic interactions, the entropic component of the system Helmholtz energy is found to play the key role in defining the overall magnitude. The latter finding appears justified by an increase in the relative delocalization of counterions upon decreasing the surface distance.

Fluorescent polypropylenes for the detection of PP-derived microplastic pollutants in organic tissues.