Oil spill is a serious threat to the environment. Six spills over 700 tons and four spills of 7-700 tons due to tanker accidents were recorded in 2024 [1]. Large oil spills can have irreversible effects on water resources and ecosystems [2]. One innovative method to solve this problem is the development of polycaprolactone-based polymeric sorbents [3]. Porous polymeric sorbents are materials that can absorb petroleum derivatives and BTEX solvents with high efficiency thanks to their porous structures. The porous structure increases the absorption capacity of the sorbent by providing a large surface area [4]. At the same time, apolar groups can selectively attract pollution thanks to their chemical compatibility with organic pollutants. The pore structure is created by using different types of porogens. Various sorbent systems are designed using solid and liquid porogens by themselves or as hybrids. The effects of these different systems on sorbent capacity were investigated. At the same time, the syntheses were carried out using bulk polymerization without using any solvent, initiator, or catalyst.
Sorbents are easy to use and collect during application and can quickly absorb large amounts of pollution because of their high absorption capacity. Sorbents repel water and collect only organic pollutants due to their hydrophobic property. In addition, sorbents can be reused, thus offering an economical and sustainable solution.
In conclusion, porous sorbents offer both an environmentally friendly and effective approach to prevent oil pollution. Such technologies can be an important step towards protecting ecosystems and providing a clean environment.

For several decades, biological materials, such as mollusk byssus, have been a source of inspiration to develop a new class of stiff and tough materials with self-repair capacity.(1) These properties are often related to the presence of sacrificial bonds releasing hidden length.(1) While giving interesting properties to the network, weak bonds have major drawbacks (lower mechanical strength, bad shape persistence, e.g.) due to an overall lower strength and faster dynamics. Therefore, developing a strategy to exploit weak bonds while limiting their drawbacks presents a strong interest.

Even though the concepts of sacrificial bond and hidden length have been explored in several materials such as elastomers or hydrogels(2,3), their use has not yet been exploited to its full potential due to the mostly empirical approaches used to develop these materials.(4) In this project our aim is to investigate in depth the impact of inserting tethered weak bonds into polymeric materials. The studied networks rely on metallo-supramolecular weak bonds connected by an oligo (ethylene glycol) linker.

Here, we present the development of an “ideal” model network based on 4-arm star poly(ethylene glycol) linked by tethered metal-ligand coordination bonds. We develop first the design and synthesis strategies for obtaining such network using a terpyridine-based crosslinker. Then, we use a combination of solid-state and DQ-NMR to gain insight into the composition and structure of the network. Finally, we highlight the dynamic behavior of the metal-ligand bonds through rheological and mechanical measurements .

Many efforts in polymer science aim towards new materials by controlling stability and the state of suitable bonds. The introduction of crosslinks, physical or covalent, between polymer chains leads to the formation of polymer networks with unique properties. In comparison to polymer networks with permanent covalent crosslinks, networks with dynamic covalent crosslinks feature chain mobility and adaptivity to external triggers. This is frequently fused in the design of shape-memory, self-healing materials and stimuli-responsive polymer gels.¹ It is desirable to transfer bond reversibility under ambient conditions also to the class of polyesters, rendering materials with tunable mechanical properties and often inherent degradability.

This project investigates the physical, thermal and morphological properties of the dynamic covalent networks derived from polycaprolactone-based copolyesters. These properties are examined via copolymers of caprolactone and either α-chloro-ε-caprolactone (αClεCL) or 1,4,8-trioxaspiro-[4.6]-9-undecanone (TOSUO) with crosslinkable chlorine and hydroxyl functionalities respectively. The dynamic covalent bond between the chains varies from a disulphide bridge to an imine bond concerning the chlorine and the hydroxyl functionality on the copolymer side-chain. The type of the dynamic bond in return, determines the stimuli such as light, pH or temperature with which bond reversibility occurs (Figure 1). Characterization techniques primarily include differential scanning calorimetry, thermo gravimetric analysis, small and wide-angle X-ray scattering, proton NMR spectroscopy and size exclusion chromatography.

Conventional polyurethane (PU) foams are thermoset materials that are profusely exploited in our society. However, they are produced from toxic isocyanates and are difficult to recycle. CO₂ self-blown polyhydroxyurethane (PHU) foams represent a promising alternative. Their production from the polyaddition between polycyclic carbonates and polyamines enables the introduction of hydroxyurethane linkages, which are dynamic through transcarbamoylation reactions. This intrinsic dynamicity within a thermoset material characterizes PHU foams as covalent adaptable networks (CANs), a crucial asset for their recyclability. However, as transcarbamoylation reactions are slow and require high temperatures (~160 °C), side reactions occur during the recycling. Therefore, we elaborated new PHU foams that feature dual dynamic bonds, through the incorporation of dynamic disulfide bonds via the use of cystamine in the formulation. These additional dynamic bonds facilitate the reprocessing of the material through a momentary de-crosslinking under milder heat stimulus. This was attested through the fast and easy (5 min, 120 °C, < 1 ton) reprocessing of cystamine-based PHU foams into films. The dynamicity of disulfide bonds was further studied through stress-relaxation experiments. This highlighted a clear correlation between the relaxation of the network and both the disulfide-bond concentration and the relaxation temperature. More importantly, this study enabled the discovery of a water-dependant relaxation of our cystamine-based samples, with significantly reduced relaxation times in presence of water. Finally, we established that our samples could be used as adhesives, particularly for stainless steel, with performance similar to commercially available glues, with higher creep resistance, and unique reusability after breakage.

Amphiphilic block copolymers self-assemble into micelles of different shapes in aqueous solutions and form hydrogels if the polymer concentration is sufficiently high [1]. The micelle and gel formation of triblock terpolymers with pH- and thermoresponsive blocks are of particular interest, as the incorporation of functional segments in block copolymers enhances the tunability of the nanostructures. Here, the effect of temperature and pH value on the self-assembly of a dual-responsive terpolymer featuring three different blocks is addressed. It consists of the hydrophobic polymethyl methacrylate (PMMA, A), the pH- and thermoresponsive poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, B) with a pKa of 7.6, and the poly(N-(2-methacryloyloxyethyl)pyrrolidone) (PNMEP, C) with a pKa of 5.2 [2]. More specifically, a PDMAEMA29-b-PMMA30-b-PNMEP16 (ABC) triblock terpolymer is investigated in aqueous solution.
Synchrotron small-angle X-ray scattering (SAXS) measurements on a 1 wt% solution in H2O of this polymer elucidate the effect of the charge state and temperature on the self-assembly into micelles. When the pH value is lower than the pKa of either of the responsive blocks, the micellar structure shows only a weak temperature dependence, because the charges hinder the coil-to-globule transition even when the temperature is above the cloud point of responsive blocks. When the pH is above both pKa values, the blocks are uncharged and flexible, which allows a temperature-induced cylinder-to-sphere shape change of the micelles. Thus, the self-assembly behavior of the triblock terpolymer in aqueous solution is largely governed by the water solubilities and the charge states of the blocks.

Polymer-based adhesives commonly used to join different materials present several issues at the end-of-life of composite structures. To enhance the circularity of bonded polymer parts, de-bondable on-demand adhesives present a promising method to disassemble composites in a viable timeframe, to recover the joint components without damages, and to reuse them.1 External stimuli, including temperature and light, can trigger cohesive and/or adhesive failure of bonded structures.2,3 A prominent strategy involves the use of polymer networks with dynamic covalent bonds that are able to undergo bond exchange reactions when exposed to specific triggers. The related change in the viscoelastic properties (at elevated temperature) is then exploited for debonding processes. In our work, we introduced a chemical amplification mechanism in which a single external trigger induced a cascade of subsequent reactions in dynamic polymer networks.3,4 Upon thermal activation, a super acid is released, which on the one hand removes protecting group (t-BOC) from hydroxy functions in the polymer and on the other hand acts as transesterification catalyst.5
In the presence of the activated catalyst and the free -OH groups available, the network is able to undergo thermo-activated transesterification, which is evidenced by a rapid decrease in stress relaxation. Transferring this concept to adhesives, we followed the change in the bonding performance prior to and after activation of the cascade reaction as a function of selected external stimulus.

Amines play a significant role in materials science, especially as crosslinkers [1]. In the field of polymers and, in particular, in the contest of covalent adaptable networks (CANs)[2,3], multifunctional amino-terminated molecules have become crucial in the development of recyclable materials based on various exchange chemistries [2,3]. This drives a significant interest in the development of novel polyamine crosslinkers. Moreover, the precise control over the macromolecular architecture, obtainable by Atom Transfer Radical Polymerization (ATRP), can be used to fine-tune the mechanical properties of the resulting materials.
Herein, we describe the use of star-shaped amino-terminated polystyrenes, obtained by Activators Regenerated by Electron Transfer (ARGET) ATRP, as rigid crosslinkers in both conventional thermosets and CANs.

Biomolecular condensates and coacervates are liquid droplets formed by liquid-liquid phase separation1,2. Coacervates are often used as mimics of condensates, but there is a fundamental difference between them. In cells, biomolecular condensates appear and disappear, and their properties change over time in a process called aging. On the other hand, coacervates are normally studied as equilibrium structures whose properties remain constant.

The formation of coacervates can be influenced by pH, temperature, ionic strength, and other parameters. Here, we aim to develop a protocol to do aging in coacervates. Our objective is to find a general method that works for all coacervates, so instead of targeting the chemical structure of the polyelectrolytes we target the salt – we have to find a salt that changes over time. For this purpose, we used ammonium carbonate, a salt known to evaporate.

In this project, as ammonium carbonate evaporates, we observe the formation and subsequent disappearance of coacervates as the salt concentration crosses the critical salt concentrations of the system. The rate of volatilization of ammonium carbonate is affected by various conditions such as temperature, and stirring rate. By stirring and heating, we can increase the evaporation rate of salt, thereby controlling the times at which coacervates form and precipitate.

Controlling supramolecular interactions is challenging, yet critical to many applications. Even for “simple” supramolecular architectures, self-assembly in non-optimal conditions can lead to multiple structures with different properties.[1] A similar case can be made for crystallization; for instance, forming protein crystals requires a non-trivial optimization of the conditions to obtain well-defined structures.[2,3] To facilitate these processes, we aim to develop new solvents where supramolecular interactions can be precisely tuned.

Coacervates are liquid droplets that form spontaneously due to the interactions of a single polymer with itself, or between two oppositely charged polyelectrolytes. They are aqueous, but they contain most of the polymer chains from the solution, which makes them relatively hydrophobic while containing a larger density of charges.[4] Due to this unusual combination of hydrophobicity and charges, coacervates solubilize most molecules. Both polar and apolar solutes are more soluble in the coacervate phase than in water, which leads to their spontaneous concentration and compartmentalization into coacervate droplets, and their depletion from the rest of the solution.[5]

In this study, we investigate how the unique environment within coacervates influences supramolecular self-assembly and crystallization, and study how the responsiveness of the coacervate phase translates to the compartmentalized structures. By tuning the ionic strength and polyelectrolyte composition, we explore how different properties of the coacervates affect crystalline nucleation and growth. Finally, we introduce lipid membranes around coacervates, allowing for salt exchange while restricting macromolecule diffusion.[4] This permits us to gradually tune the solubility of the compartmentalized molecules, leading to localized supersaturation and controlled crystallization.

Metallopolymers combine the advantages of “classical” organic polymers, such as lightweight, tunability, and cost-effectiveness¹ with the unique properties of metal complexes, including catalytic activity, bioactivity,² and conductivity.³ This synergy makes them promising materials for different applications, such as self-healing polymers,⁴ shape memory polymers, and smart materials.⁵ However, a key challenge lies in understanding their structural dynamics.
In this study, we investigate terpyridine-based metallopolymers complexed with iron(II) or zinc(II) ions to gain deeper insights into their dynamic behavior. These materials were synthesized and characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and elemental analysis (EA). Rheological methods including dynamic mechanical thermal analysis (DMTA), frequency sweeps, stress relaxation, and time-temperature superposition were employed to examine their viscoelastic properties. Additionally, temperature-dependent Raman spectroscopy and density functional theory (DFT) calculations provided insights on the molecular level. Our findings reveal a reversible activation of the metal complexes in zinc(II)-containing metallopolymers, as observed in frequency sweep measurements. Raman spectroscopy confirmed these results, showing morphological changes in the polymer matrix without structural modifications of the metal complex. Furthermore, it was possible to calculate the activation energies for dynamic interactions within the metallopolymers. This study provides a more comprehensive understanding of the dynamic behavior of metallopolymers that could lead to the development of new smart materials with tunable properties.

Polyesters are a versatile and widely used class of polymers, integral to numerous industrial applications, functioning as either thermoplastic materials or thermosetting (crosslinked) resins.1 While the ester bonds in thermoplastics allow for recycling, the process often compromises material integrity trough molecular weight reduction caused by high thermal input.2 Conversely, thermosetting materials face significant challenges in recycling due to their rigid, crosslinked structure, which limits reprocessability.3
The introduction of vitrimeric properties into polyester systems offers a promising pathway to address these challenges. Vitrimers, characterized by their dynamic covalent bonds, allow the thermosetting polymers to be reprocessed without compromising their mechanical integrity at service temperatures. For thermoplastics, vitrimeric behaviour mitigates molecular weight reduction by facilitating bond exchange reactions that restore and maintain network integrity.
In this work, we focus on the development of latent catalysts tailored to impart vitrimeric dynamic properties to polyesters. These catalysts, based on amine base salts4 and N-heterocyclic carbenes5, remain inactive under standard service conditions but activate upon the application of heat. Upon activation these catalysts promote transesterification reactions, facilitating dynamic bond exchange while ensuring material stability during regular use. Using a model system, we optimized these catalysts to refine their activation profiles, thermal thresholds, and catalytic efficiency. The resulting catalysts were then incorporated into polyester materials, demonstrating precise control over reprocessing conditions and bond exchange kinetics. This approach enhances the functional versatility of polyesters, enabling sustainable recycling and reprocessing while maintaining or improving material performance.

Coatings are essential in many everyday products, but their complex, multiphase structures pose significant challenges for recycling, often resulting in coated materials being discarded in landfills. To advance sustainability, it is crucial to design coatings that not only perform effectively but can also be removed on demand without damaging the underlying substrate. Phosphate esters, known for their strong ability to bind to metal substrates, are effective as adhesion promoters in various industrial applications. In this work, we develop phosphate triester networks with β-hydroxy groups protected by o-nitrobenzyl photocleavable groups to create a removable coating for metal substrates. Inspired by the self-cleaving backbone structure of RNA, our group previously developed dynamic covalent networks based on phosphate triesters incorporating neighboring β-hydroxy groups, which are highly prone to hydrolytic degradation under mild conditions.(1) In contrast, standard phosphate triester networks without these neighboring groups exhibit negligible hydrolysis at room temperature,(2) due to a high energetic barrier to transesterification in the absence of β-hydroxy-mediated exchange via a cyclic intermediate. By adding a protecting group to the β-hydroxy groups, we design a coating that resists degradation during use but can be easily dissolved upon photodeprotection. Bis-epoxy protected β-hydroxy phosphate triester monomers are synthesized and used to create versatile networks. This approach has significant potential to enhance the lifetime and recycling of metal substrates, offering a crucial step toward advancing sustainable practices in industries reliant on metal components.

Covalent adaptable networks (CANs) are crosslinked polymer structures that undergo dynamic bond exchange reactions when exposed to heat, enabling a reorganization of their topology. This distinctive property enables these polymers to combine the durability and chemical resistance of thermosets with the processing versatility and recyclability of thermoplastics. [1]

Figure 1: Thiol-Thioester exchange mechanism

We focused on thiol-thioester exchange reactions (Figure 1), which, with suitable catalysts, can proceed rapidly even at low temperatures, a characteristic that is especially relevant for biomedical applications. Initially, we produced vinyl monomers with thioester functionalities to promote network formation through a thiol-ene click reaction under visible light exposure. To achieve a spatial resolution of dynamic exchange reactions, 5 variations of TMG-based photobase generators (TMG-PLBs) were synthesized. These TMG-PLBs incorporate 1,1,3,3-Tetramethylguanidine as a strong base, along with phenylglyoxylic acid or its derivatives, which are modified with spacers or side groups. The purity of the monomers and the TMG-PLBs was characterized by 1H- and 13C-NMR spectroscopy. Via pH-measurements in water and ethanol, the basicity of the synthesized compounds in dependency on the irradiation dose was determined. Subsequently, by using equimolar amounts of thiol and vinyl monomer, 3mol% TMG-PLB and 1 mol% phenyl-bis(2,4,6-trimethylbenzoyl)phosphinoxide (BAPO), the photosensitive resin was prepared. After curing the resin via 450 nm irradiation, spatially resolved activation of the photobase was accomplished through 365 nm UV-light illumination. To explore the resulting dynamic behavior, we conducted stress relaxation measurements at various temperatures. Additionally, differential scanning calorimetry and thermogravimetric measurements were performed to investigate the thermal material properties.