We demonstrate an exceptional ability of a high-polarization 3D ferroelectric liquid to form freely suspended fluid fibers at room temperature. Unlike fluid threads in modulated smectics and columnar phases, where translational order is a prerequisite for forming liquid fibers, recently discovered ferroelectric nematic forms fibers with solely orientational molecular order. Additional stabilization mechanisms based on the polar nature of the mesophase are required for this. We propose a model for such a mechanism and show that these fibers demonstrate an exceptional nonlinear optical response and exhibit electric field-driven instabilities.

Oxidation barrier coatings on the base of a perhydropolysilazane precursor with different amounts of Si, B, SiB₆ and Mo₅SiB₂ (T2) fillers for the oxidation protection of Mo-Si-B alloys were developed. The influence of different filler compositions as well as the influence of pyrolysis conditions (temperature and atmosphere) was studied. The coating slurries were examined with respect to their rheological behavior, which allows optimization of the coating slurry. Dilatometry studies show that the coefficient of thermal expansion of the composites can be matched to refractory, especially molybdenum alloy based, substrates by varying the content and the composition of the filler. The pyrolyzed coating systems offer a low porosity, which is one of the key parameters to a high oxidation protection capability.

Digital light processing (DLP) has gained substantial interest in recent years as a versatile additive manufacturing technique across different disciplines. However, many materials used in DLP 3D printing are from non-sustainable sources. The use of renewable resources like lignin, a complex aromatic polymer derived from plant biomass and an industrial byproduct produced in ton-scale, in resins promotes the development of sustainable and environmentally friendly additive manufacturing processes and applications. Therefore, we first present a cost-effective and reproducible acrylation synthesis route that enables the modification of lignin using acryloyl chloride as a functionalization reagent. Further, we systematically investigate the effects of different contents of unmodified lignin up to 20 wt % and modified lignin with acrylate groups up to 30 wt % in resins using a time-efficient, self-developed step test to achieve optimal printing parameters with the smallest possible feature size. These parameters are used for high-resolution DLP 3D printing of microneedles for potential medical applications, which is why the cytotoxicity of the lignin resins is determined as well. The addition of lignin to resins influences their rheological properties and printability remarkably as well as the mechanical performance of the corresponding 3D-printed objects. Notably, higher lignin concentrations are found to enhance the mechanical strength of 3D-printed parts. Furthermore, we assess the effects of lignin acrylation in photopolymer formulations leading to improved solubility, substantial change in rheological properties from thixotropic to non-thixotropic behavior, and an enhanced E-modulus of 3D-printed materials. As a result, we showcase the feasibility to 3D-print with up to 30 wt % of modified lignin and present a 3D-printed material with 15 wt % of modified lignin, which is classified as non-cytotoxic according to EN ISO 10993-5. However, further increasing lignin content generally adversely affects the printability due to increased resin viscosity as well as light scattering and pronounced UV light absorption.