The increase consumer demand for long-wear cosmetics necessitates sustainable alternatives to traditional petroleum-based film-formers, which pose significant environmental concerns due to their limited biodegradability. Bio-based polymers, particularly polysaccharides, have found widespread use as stabilizers and film-forming agents in cosmetic formulations1. Among these, polyhydroxyalkanoates (PHAs) represent promising candidates to replace petroleum-derived polymers owing to their biodegradability, film-forming capabilities, low glass transition temperatures (Tg), and excellent adhesion properties2,3.
Specifically, poly(3-hydroxynonanoate) (PHN), a bio-sourced polymer, has been identified as a pioneering natural oil-based film-former for long-wear cosmetics4. This high molecular weight, semi-crystalline polymer demonstrates remarkable in vivo dry resistance, which can be further enhanced by the incorporation of natural sunflower wax. Scanning Probe Microscopy and Spectroscopy techniques, including PeakForce Quantitative Nanomechanical Mapping (PF-QNM) and Nano-Dynamic Mechanical Analysis (nano-DMA), were employed to investigate the nanoscale mechanical properties of these films. Topological images show a particle ‘like’ structuration of the PHN film exhibiting an elastic modulus of ~140 MPa. Wax addition appears to alter the film structure while preserving its mechanical properties. Furthermore, to simulate physiological skin conditions and the influence of environmental factors, polymer coatings were deposited on ex-vivo isolated skin’s outermost layer, the stratum corneum. The mechanical and viscoelastic behavior of these coatings was characterized as a function of temperature and relative humidity. Results clearly indicate enhanced miscibility under elevated temperature and humidity conditions, concomitant with a significant reduction in stiffness and good filming properties.
This study highlights the potential of the PHN platform for developing novel bio-sourced cosmetic ingredients with tunable properties. Moreover, characterizing the influence of temperature and humidity bridges the gap between laboratory measurements and real-world cosmetic performances, providing valuable insights into material behavior under conditions mimicking skin physiological parameters.

Polymers are a versatile class of materials with almost unlimited combinations of functional groups being present in close proximity. This in combination with a widely tunable solubility has enabled quite a range of examples where building blocks for light-driven catalysis (i.e., photosensitizers and catalysts) are immobilized using either covalent anchoring or non-covalent interactions. During recent years, we have developed different soft matter matrices for either light-driven hydrogen evolution (HER) or water oxidation (WOC) based on unimolecular graft copolymers, block copolymer micelles, hydrogels, or nanoporous block copolymer membranes.[1] In all cases, close proximity of the immobilized building blocks facilitated light-driven reactivity, but we also observed additional effects during our studies, such as prolonged lifetime of photosensitizers, altered degradation pathways, or the possibility to repair / exchange catalysts or sensitizers. Herein, we focus on water oxidation catalysis (WOC) using varying soft matter matrices, mainly graft copolymers and hydrogels[2, 3] – with particular emphasis on whether the matrix suffers oxidation or degradation during these processes. Altogether, we hope to derive some general guidelines for the design of (charged) soft matter matrices for light-driven catalysis.[4]

Green fluorescent protein (GFP) is a widely used genetically encoded, non-invasive marker in biological research. The GFP chromophore is formed through autocatalytic dehydration and oxidation of a Ser-Tyr-Gly tripeptide, which undergoes excited-state proton transfer, transferring a proton from the phenolic oxygen to the protein matrix, resulting in a strong green fluorescence. Upon denaturation, GFP’s fluorescence decreases by about four orders of magnitude. To mimic GFP’s photophysical properties, several synthetic chromophores have been developed. However, these generally exhibit weak fluorescence (Φ < 10–2) in bulk solutions at room temperature, mainly due to rapid internal conversion caused by unrestricted rotational movement of the chromophores involved leading to non-radiative decay. 1-3
Due to their photophysical properties related to fluorescence and their rigid heteroaromatic structure that can limit the intramolecular motions 4, diketopyrrolopyrroles (DPPs) present a promising class of dyes for the development of GFP analogues. For this reason, in this work novel emissive monomers based on N-alkylated DPP have been designed and properly polymerized to obtain copolyesters with specific design. The conformation of the polymer chain reduces π–π interactions between chromophores, and the fluorophore’s geometry limits unwanted rotational and vibrational motions, leading to enhanced fluorescence. These structures help to improve the emissive properties compared to traditional synthetic chromophores. Furthermore, the photophysical and thermal characteristics of these materials can be tuned by modifying the DPP functionalization and adjusting the copolymer composition. This enables precise control over the fluorescence behaviour, making these DPP-based copolyesters promising candidates for applications requiring stable, efficient light emission.

The increasing demand for sustainable, energy-efficient water disinfection highlights the need for innovative advanced oxidation methods powered by renewable energy. Among these, photodynamically active polymer-based systems offer a promising route for residue-free disinfection by generating reactive oxygen species (ROS) under light exposure.
Phthalocyanine derivatives, well-known for their strong absorption in the red and near-infrared regions, serve as efficient photosensitizers (PS) in photodynamic therapy (PDT).[1] When integrated with electrospun polymer carriers, these systems provide enhanced stability, controlled ROS release, and improved antimicrobial activity.[2]
The polymer matrix not only influences key factors such as hydrophilicity, porosity, and mechanical properties but also photosensitizer dispersion and photoinduced efficacy.[3] By tailoring the structure and composition of both the photosensitizer and polymer, the performance of PDT-based antimicrobial materials can be significantly improved. The design, synthesis, and structure-activity relationships of such nanoscale systems, aiming to advance their effectiveness and expand their application scope in biomedical and environmental disinfection technologies will be presented.

Filled elastomers are a major class of nanocomposites with numerous applications including tyres. Such materials are constituted of a sulfur vulcanized dienic rubber containing about 20 vol.% of a stiff filler (either carbon black, or silica covered with a sulfur containing reagent) strongly interacting with the elastomer network. Cellulose nanocrystals constitute an attractive alternative filler thanks to their specific features (biosourced, low density, anisotropic morphology and mechanical properties). A key step toward their employement is the possibility to introduce disulfide groups onto their surface. While conventional cellulose chemistries shall be efficient, they are not sustainable (organic solvent, large excess of reagent) and we recently investigated two greener strategies to solve that issue. The first one is suited for the conventional melt processing of rubber materials with filler powders. Herein the chemical modification is performed along a solvent free gas-phase surface esterification of high specific surface area cellulose nanocrystals powders. [1] The second one is adapted to an emerging alternative processing, the so called liquid phase mixing, which relies on the coagulation of binary colloidal mixtures obtained from water dispersions of rubber and cellulose nanocrystals. In such case an aqueous two steps strategies have been investigated (cellulose surface oxidation, followed by the coupling of an amino disulfide reagent). [2] In this talk, I will detail the efficiency of such chemical modification pathways, and present some data on the microstructure and mechanical properties of the resulting materials obtained by these two processing routes.

Concentrated nanocarbon dispersions of MWCNT and graphene have been prepared by top-down processing in water stabilized by poly(ionic liquid)s, PILs, derived from imidazolium-based ionic liquids. Advanced materials of such dispersions are produced by scalable coating methods, including shear (draw-down bar), electrospinning, and controlled destabilization-sedimentation. Shear-coating produces conformal coatings of MWCNT, multiwall carbon nanotubes (Figure 1a), and graphene (Figure 1b) of nominal electrical conductivity but of very high thermal conductivity, 3 kW/m/K, in the case of MWCNT. Electrospinning produces novel heterostructured coatings of graphene (Figure 1c) and MWCNT (Figure 1d) of high specific surface area that are promising materials for electrodes and catalytic membranes. Controlled destabilization-sedimentation utilizes the stimuli-responsiveness of the PIL stabilizer to produce meso-crystallization of graphene (Figure 1e and Figure 1f). Coating mechanisms, applications, stimuli-responsiveness, and limitations of such advanced coating materials are presented.