ABSTRACT Silicone rubbers have been widely employed in advanced polymeric materials and lab‐on‐a‐chip devices owing to their ease of fabrication, biocompatibility, transparency, and oxygen permeability. However, their practicality is often limited by deformability, surface tackiness, drug sorption, and leaching of low‐molecular‐weight siloxanes, which raises cytocompatibility concerns. Here, we present a systematic study on the bulk modification of silicone rubber via electron beam (EB) irradiation at practically relevant doses (100–1000 kGy). EB irradiation increased the compressive modulus, slightly enhanced hydrophilicity, and significantly reduced surface tackiness, while maintaining high oxygen permeability and optical transparency. The process also markedly reduced low‐molecular‐weight cyclic siloxanes, including D4, a compound known for cytotoxicity. Correlation analysis indicated that the reduction in tackiness strongly corresponded with the decrease in low‐molecular‐weight siloxane content. Although drug sorption remained unchanged, likely due to the intrinsic porosity of silicone rubber, these results demonstrate that EB irradiation is a practical bulk modification strategy that enhances mechanical robustness and cytocompatibility while preserving key physicochemical properties. The process is suitable for batch‐scale industrial manufacturing. Furthermore, an EB‐modified spheroid formation device was fabricated to demonstrate its functional utility, enabling the high‐throughput generation of human induced pluripotent stem cell (iPSC) aggregates while alleviating hypoxic conditions.

ABSTRACT Metal‐free polymerization is required to prevent contamination of polymeric materials by residual metal catalysts. In this study, the ring‐opening polymerization (ROP) of ε ‐caprolactone (CL) is investigated under bulk conditions at 100°C using benzyl alcohol (BnOH) as the initiator and seven environmentally benign organic acids (EBOAs) as activators (catalysts). In all cases, ROP yields poly( ε ‐caprolactone) (PCL) with narrow polydispersities ( Ð ). Kinetic analysis shows first‐order behavior, indicating a controlled process. The reaction rate constant ( k ) correlates with the acidity (p K a ) of EBOAs, with stronger acids (lower p K a ) exhibiting higher catalytic activity among those tested. Substituting BnOH with alternative alcohol initiators produces PCL bearing well‐defined heterotelechelic end groups, such as ally or polyethylene glycol moieties. Hydroxy‐terminated PCL enables further post‐polymerization, including chain extension and block polymerization (poly( ε ‐caprolactone)– b– poly( δ ‐valerolactone); PCL– b– PVL) with δ ‐valerolactone using EBOAs, while preserving narrow Ð . Moreover, the composition unit in PCL– b– PVL can be tuned by selecting EBOAs of different acidity, directly influencing catalytic activity. This controlled EBOA‐based system is useful for applications where metal contamination must be avoided, such as polymeric biomaterials.

ABSTRACT The selection of the appropriate materials and structures for enhanced energy absorption is paramount in the design of protective gear, regardless of the final application. This research addresses a long‐standing academic debate regarding the effectiveness of auxetic structures in mitigating impacts relative to open‐cell foam counterparts by developing a comparative, energy‐based framework to conclusively establish auxetic structures as the superior option. The framework calculates the energetic performance across the elastic, plateau, and densification regions, utilizing consistent bulk material: polyurea, irrespective of the type of cellular solid (open‐cell foam vs. re‐entrant auxetic). The material properties were found to play a major role in the mechanical performance of open‐cell foams; therefore, they were investigated parametrically. Furthermore, the study examines the critical effect of the auxetic structure's characteristic re‐entrant angle on its energy absorption mechanisms. The results demonstrate that the auxetic structures significantly outperform the open‐cell foams, reporting a four‐fold increase in specific energy absorption. This outcome definitively concludes the discussion in favor of auxetic metamaterials. Crucially, amplifying the initial auxetic angle resulted in a significant seven‐fold increase in energy absorption across the explored re‐entrant range (50° to 85°), providing mechanical designers with a powerful new tool for tailoring energy absorption properties.

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.

ABSTRACT Chronic wounds affect millions of people worldwide, and their treatment can often be ineffective, resulting in substantial healthcare costs. Due to their prolonged healing time and susceptibility to infections, their treatment can be complex. Although there are various treatments available (scaffolds, dressings, etc.), there are limited studies outlining the use of external stimuli, particularly electrical stimulation, to facilitate wound healing. It is well established that electric fields influence the migration, proliferation, and differentiation of cells, along with re‐epithelialization and vascularization of wounds. Thus, exogenous electrostimulation may be a promising strategy to replicate or enhance these effects and improve wound healing outcomes. In this study, the fabrication of conductive polypyrrole films with encapsulated antimicrobial agent, nisin, for electro‐responsive drug delivery is presented. The films were fabricated via electrodeposition, and in vitro experiments demonstrated good biocompatibility with fibroblast and keratinocyte cells. Additionally, the release of the entrapped drug was observed using a minimal applied potential, and the films showed significantly low bacterial cell adhesion and increased adhesion of HeLa cells, including electrically triggered shape transformations. The findings in this proof‐of‐concept study highlight the potential of electro‐responsive films to enhance the efficacy of wound healing and drug delivery combinatory therapies using external stimuli.

ABSTRACT Improving the treatment of nerve diseases through the development of a suitable hydrogel scaffold is currently an unmet clinical need. This study investigates the fabrication and optimization of a conductive hydrogel scaffold produced from Gelatin Methacryloyl (GelMA), chitosan, polypyrrole (PPy), and multi‐walled carbon nanotubes (MWCNT). Following optimization of GelMA (15 w/v%) and chitosan (2 w/v%) composition, PPy was incorporated at varying concentrations (0.5, 1, and 2 w/v%), and comprehensive physiochemical and mechanical characterizations were performed. PPy at 1 w/v% was chosen as the optimized concentration. Functionalized MWCNTs were then added at 0.5, 1, and 2 w/v% to the optimized composition to create a conductive composite with enhanced characteristics suitable for nervous tissue. A significant increase in electrical conductivity was recorded with the addition of 1% MWCNT, enhancing the conductivity from 0.91 to 1.54 S m −1 . Additionally, the biocomposite hydrogels exhibited compressive strength and modulus of 0.75 MPa and 2.95 MPa, respectively. With an increase in MWCNT, cell proliferation and adhesion of PC12 and SH‐SY5Y were found to be more effective in GelMA‐Chitosan‐1% PPy‐1% MWCNT. Vitamin C was incorporated into the optimized system as a model therapeutic agent, exhibiting release behavior consistent with the Korsmeyer‐Peppas model, while significantly enhancing antioxidant activity and reducing reactive oxygen species. Overall, these findings suggest that the developed hydrogel represents a promising platform for nerve tissue repair.

ABSTRACT Novel biobased polymers based on lignin building blocks are synthesized and systematically characterized. The three prominent aromatic aldehydes that can be obtained from oxidative degradation of lignin, namely p‐hydroxybenzaldehyde (H), vanillin (V), and syringaldehyde (S), are chemically modified into radically polymerizable styrenic monomers presenting either a methoxy or butoxy (‐OBu) group at the para‐position. The transformation of these molecules is accomplished and optimized individually on each compound. Subsequently, polymers are successfully prepared by free radical polymerization in homogeneous conditions (in solution using ethyl lactate as green solvent) and in heterogeneous conditions (in aqueous emulsion using a biosourced surfactant). Novel polymeric materials with high thermal stability and a glass transition temperature (Tg) tunable between 40°C and 110°C are obtained, depending on the monomer used.

ABSTRACT The methacrylation of Beech organosolv Lignin with methacrylic anhydride (MA) at 65°C under [4‐ (dimethylamino) pyridine] (DMAP) base catalysis is monitored by the FTIR OH‐stretch at 3340cm −1 and the C═C vibrations associated with the methacrylate group at 780, 810, 945, and 1637 cm −1 . Methacrylation extent increases with the MA: lignin OH molar ratio, the DMAP: MA wt%, and their interactions. Monitoring these vibrations over 48 h suggests side reactions, liberating new OH functionalities and, in turn, new grafting sites. Under these conditions, zero‐ and second‐order kinetics fit the kinetics of lignin methacrylation equally well. Lignin methacrylate derivatives cure readily under UV light, and both the cure rate and full cure extent increase with increasing methacrylate conversion of lignin OH. The Sestak‐Berggren autocatalytic kinetic model successfully describes UV‐photocure, whereby the product autocatalytic (m) and reactant's exhaustion retardation (n) effects decrease with increasing methacrylation extent, from ca. 0.34 to 0.28 and from ca. 1.05 to 0.67, respectively. Lignin methacrylation can thus be tuned to adjust rheological and photocuring properties of methacrylate lignins for UV light induced processing, such as 3D printing.

ABSTRACT Poly(trimethylene terephthalate) (PTT) is a widely used engineering polyester, but its petroleum‐derived monomers conflict with current efforts to reduce reliance on fossil feedstocks. Poly(trimethylene 2,5‐furandicarboxylate) (PTF), a fully bio‐based analogue with properties comparable to PTT, is a promising alternative, yet the impact of chemical modifications such as copolymerization remains poorly explored. This work combines mathematical modeling with experimental characterization to predict and validate key thermal and structural properties of bio‐based polyesters and copolyesters. This study underlined the successful synthesis of two series of bio‐based copolymers, i.e. poly(trimethylene terephthalate‐co‐trimethylene glutarate) PTT‐co‐PTG and poly(trimethylene 2,5‐furandicarboxylate‐co‐trimethylene glutarate) (PTF‐co‐PTG) via melt polycondensation. The chemical structure and composition of the copolymers were confirmed with the use of 1 H NMR spectroscopy. Limiting viscosity numbers (LVNs) ranging from 0.643 to 0.759 dL/g were obtained, indicating that the desired values were achieved. The influence of the incorporation of PTG units on thermal properties and morphology was investigated using differential scanning calorimetry (DSC). There were no significant differences in thermal stability and activation energy between the homopolymer and the corresponding copolymers.