BASF (Switzerland)

Understanding interactions between reactive species and surfaces is a central task in materials science and heterogeneous catalysis. Decades of research have produced strategies to automatically detects surface active sites on computationally modeled slabs, leveraging symmetry, tessellation or relying on efficient dynamics. Regardless of the method or protocol, the quality of starting configurations (fragment-surface structures) remains pivotal. However, a universal, systematic approach for placing any molecular species on any surface remains lacking. For complex interfaces, where automatic protocols reach their limit, human curation of configurations is required, making the study of such systems slow, biased and unscalable. Machine learning approaches offer a promising alternative, but they demand large, diverse, and unbiased datasets—highlighting the need for better data generation strategies. We introduce Surrogate-SMILES (*SMILES), a representation of molecules and their fragments bound to surfaces, along with AutoAdsorbate, an automated method for generating chemically meaningful configurations of any molecule (or fragment) on any surface. Our approach enables uniform sampling and the creation of high-quality datasets, supporting both physics-based simulations and data-driven models—including one-shot learning and efficient initialization of active learning protocols for interatomic potentials. This advancement expands applications across catalysis, nanotechnology, and environmental science, where precise control over surface interactions is essential for the rational design of functional materials.

Liquid acrylic oligourethanes are components of photocurable thermoset resins for applications ranging from coatings to 3D printing technologies like stereolithography. Traditionally they are derived from isocyanates which are highly moisture sensitive and do not tolerate hydroxy groups. Herein we report on a versatile non-isocyanate route toward tailoring hydroxyurethane methacrylates (HUMA) and their oligomers for photo cross-linking and 3D printing. The key intermediate is (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate, also referred to as methacrylated glycerol carbonate, obtained by the chemical fixation of carbon dioxide with glycidyl methacrylate. Upon aminolysis with di- and polyfunctional aliphatic amines, the ring-opening reaction of the cyclic carbonate group yields HUMA. No handling of isocyanates is required. The HUMA molecular architectures govern photo cure as well as thermal and mechanical properties. An alternative strategy toward molecular design of polyfunctional acrylics exploits chemical modification of the pendant hydroxy groups, e.g., by esterification with methacrylic acid anhydride. The resulting higher acrylate functionality accounts for improving Young's modulus from 3160 to 4200 MPa and increasing the glass transition temperature from 86 to 173 °C with respect to HUMA-based formulations.

This article describes some selected results of my 30 years as an industrial researcher. During this time, I had the chance to work on many very different projects. About two thirds of them were dealing with the fascinating interaction of radicals and polymers. Of the more than 350 million tons of industrial polymers produced worldwide every year, about 50% are made by the radical polymerization of monomers that are often stabilized against undesired premature polymerization by addition of polymerization inhibitors. Stabilizers are necessary to protect the majority of polymeric materials during their service life from radical degradation processes triggered by oxygen, heat or light. Modification of the polymeric architecture can be easily achieved via radical polymer analogous reactions. One of the most important developments in polymer science in the last 25 years is controlled radical polymerization. Recently, radical bearing redox-active polymers emerged as promising in energy storage applications, for example, in organic radical batteries. Our contributions to the fields mentioned above are described with examples of: a) novel benzofuranone stabilizers for polymers; b) the serendipidous discovery of novel dyestuffs; c) eco-friendly polymerization inhibitors; d) novel nitroxides and alkoxyamines for the first industrial realization of controlled radical polymerization; e) novel and safe radical initiators; f) nitroxide radicals bearing polymers for electrochemical applications.

Crucial to the development and refinement of organic electronics is a fundamental understanding of how deposition processes affect the active material’s resulting microstructure in the thin film. Meniscus-guided coating (MGC) methods are attractive because of their amenability to high-throughput, industrially relevant continuous processes like roll-to-roll deposition, but the mechanism of solid film formation has not been elucidated and is valuable for the precise control of thin-film morphology and thus ultimate device performance. Here, in this work, we investigate the microstructural evolution of thin films of a diketopyrrolopyrrole–terthiophene donor–acceptor polymer semiconductor using both in situ and ex situ X-ray diffraction methods. On the basis of a comparison of disorder between the film bulk and the top surface and a depth profiling of the out-of-plane orientation of crystallites, we find that faster coating speeds introduce more disorder into the resulting films because the stochastic nucleation of disordered crystallites at the meniscus air–liquid interface becomes more dominant than substrate-mediated nucleation. Our results suggest that there exist three separate deposition regimes—namely the shear-dominate, disorder-dominate, and Landau–Levich–Derjaguin regimes—revealed by observing both polymer alignment via dry film thickness and optical dichroism, a property sensitive to the flow and shear fields. At low coating speeds, the shear strain imparted upon the solution directly induces polymer alignment, causing an increase in dichroism as a function of coating speed. When solvent evaporation becomes too rapid as coating speeds increase, a decrease in the dichroic ratio is observed before the classical Landau–Levich–Derjaguin regime occurs at the highest coating speeds, resulting in isotropic films. The preservation of out-of-plane crystalline texture throughout the thickness of the films is seen only for lower coating speeds, and a study of different deposition temperatures similarly indicates that the lower overall solvent evaporation is conducive to this process. Increased paracrystalline disorder (i.e., peak broadening) is observed by grazing-incidence wide-angle X-ray diffraction at the top interface of the dry films and at higher coating speeds. Together, these results indicate that more rapid solvent evaporation at higher coating speeds causes increased disorder, which can cause the nucleation of misaligned crystallites, affect the dichroic ratio, and may frustrate the alignment of polymer molecules in the amorphous regions of the film. Finally, because the polymer studied and the deposition technique used are representative models, these results are likely general for aggregating, semicrystalline donor–acceptor polymers deposited with MGC.

Novel glazing with embedded micro-mirrors can significantly reduce the energy consumption due to cooling and lighting in buildings. Especially promising are large arrays of periodic micro compound-parabolic-concentrators (CPCs) with angular-selected transmittance. For the production of micro CPCs, curved sidewall grooves with a controlled optical surface and an aspect ratio of about 2.3 are fabricated on polycarbonate substrates by scanning nanosecond 248-nm excimer laser ablation. The likewise obtained microstructures can be used as master mold for replication. The cross-sections of the micro grooves are characterized by confocal microscopy, and the extracted morphologies are used for the ray-tracing simulation of the optical devices. Prior to the scanning ablation using a suitable mask in the optical path, the depth profiles under static ablation are investigated to identify ablation rate, imaging resolution and produced surface. Interestingly for the width of the mask opening being less than 6 μm, the ablation rate is increased due to optical interference and /or less shielding by debris. Concerning the scanning ablation, the depth of the curved sidewall grooves ranges from 48 μm to 114 μm, corresponding to the width of the groove opening being in the range from 20 μm to 50 μm. The observed final shapes in cross-sections are in good agreement with the design of the mask. For both theoretical and fabricated groove shapes, the angular-selected transmittance profiles predicted from ray-tracing simulations are highly similar. Scanning nanosecond excimer laser ablation is therefore a promising approach for the realization of high-quality micro CPCs.

The charge-carrier mobility of organic semiconducting polymers is known to be enhanced when the energetic disorder of the polymer is minimized. Fused, planar aromatic ring structures contribute to reducing the polymer conformational disorder, as demonstrated by polymers containing the indacenodithiophene (IDT) repeat unit, which have both a low Urbach energy and a high mobility in thin-film-transistor (TFT) devices. Expanding on this design motif, copolymers containing the dithiopheneindenofluorene repeat unit are synthesized, which extends the fused aromatic structure with two additional phenyl rings, further rigidifying the polymer backbone. A range of copolymers are prepared and their electrical properties and thin-film morphology evaluated, with the co-benzothiadiazole polymer having a twofold increase in hole mobility when compared to the IDT analog, reaching values of almost 3 cm2 V-1 s-1 in bottom-gate top-contact organic field-effect transistors.

Diketopyrrolopyrroles (DPP) are a relatively new class of organic high-performance pigments. The present inhalation and particle characterization studies were performed to compare the effects of five DPP-based pigments (coarse and fine Pigment Red 254, coarse and fine meta-chloro DPP isomer and one form of mixed chlorinated DPP isomers) and compare it to coarse and fine inorganic Pigment Red 101. Wistar rats were exposed head-nose to atmospheres of the respective materials for 6 h/day on 5 consecutive days. Target concentrations were 30 mg/m3 as high dose for all compounds and selected based occupational exposure limits for respirable nuisance dust. Toxicity was determined after end of exposure and after 3-week recovery using broncho-alveolar lavage fluid (BALF) and microscopic examinations of the entire respiratory tract. Mixed chlorinated DPP isomers and coarse meta-chloro DPP isomer caused marginal changes in BALF, consisting of slight increases of polymorphonuclear neutrophils, and in case of coarse meta-chloro DPP increased MCP-1 and osteopontin levels. Mixed chlorinated DPP isomers, Pigment Red 254, and meta-chloro DPP caused pigment deposits and phagocytosis by alveolar macrophages, slight hypertrophy/hyperplasia of the bronchioles and alveolar ducts, but without evidence of inflammation. In contrast, only pigment deposition and pigment phagocytosis were observed after exposure to Pigment Red 101. All pigments were tolerated well and caused only marginal effects in BALF or no effects at all. Only minor effects were seen on the lung by microscopic examination. There was no evidence of systemic inflammation based on acute-phase protein levels in blood.

Targeting flexible display backplanes and circuitry, BASF is developing high performance materials for Organic Field‐Effect Transistors. Here we present our recent development focusing on directly photo‐patternable semiconductors and dielectrics, as well as new semiconductors for solution‐processed transistors with mobilities of up to 4 cm 2 /Vs.

Because of ethical and regulatory reasons, several nonanimal test methods to assess the skin sensitization potential of chemicals have been developed and validated. In contrast to in vivo methods, they lack or provide limited metabolic capacity. For this reason, identification of pro-haptens but also pre-haptens, which require molecular transformations to gain peptide reactivity, is a challenge for these methods. In this study, 27 pre- and pro-haptens were tested using nonanimal test methods. Of these, 18 provided true positive results in the direct peptide reactivity assay (DPRA; sensitivity of 67%), although lacking structural alerts for direct peptide reactivity. The reaction mechanisms leading to peptide depletion in the DPRA were therefore elucidated using mass spectrometry. Hapten-peptide adducts were identified for 13 of the 18 chemicals indicating that these pre-haptens were activated and that peptide binding occurred. Positive results for five of the 18 chemicals can be explained by dipeptide formations or the oxidation of the sulfhydryl group of the peptide. Nine of the 27 chemicals were tested negative in the DPRA. Of these, four yielded true positive results in the keratinocyte and dendritic cell based assays. Likewise, 16 of the 18 chemicals tested positive in the DPRA were also positive in either one or both of the cell-based assays. A combination of DPRA, KeratinoSens, and h-CLAT used in a 2 out of 3 weight of evidence (WoE) approach identified 22 of the 27 pre- and pro-haptens correctly (sensitivity of 81%), exhibiting a similar sensitivity as for directly acting haptens. This analysis shows that the combination of in chemico and in vitro test methods is suitable to identify pre-haptens and the majority of pro-haptens.

It is shown that the performance of inverted organic solar cells can be significantly improved by facilitating the formation of a quasi‐ohmic contact via solution‐processed alkali hydroxide (AOH) interlayers on top of n‐type metal oxide (aluminum zinc oxide, AZO, and zinc oxide, ZnO) layers. AOHs significantly reduce the work function of metal oxides, and are further proven to effectively passivate defect states in these metal oxides. The interfacial energetics of these electron collecting contacts with a prototypical electron acceptor (C60) are investigated to reveal the presence of a large interface dipole and a new interface state between the Fermi energy and the C60 highest occupied molecular orbital for AOH‐modified AZO contacts. These novel interfacial gap states are a result of ground‐state electron transfer from the metal hydroxide‐functionalized AZO contact to the adsorbed molecules, which are hypothesized to be electronically hybridized with the contact. These interface states tail all the way to the Fermi energy, providing for a highly n‐doped (metal‐like) interfacial molecular layer. Furthermore, the strong “light‐soaking” effect is no longer observed in devices with a AOH interface.