Columnar supramolecular phases with polarization along the columnar axis have potential for the development of ultrahigh‐density memories as every single column might function as a memory element. By investigating structure and disorder for four columnar benzene‐1,3,5‐trisamides by total X‐ray scattering and DFT calculations, we demonstrate that the column orientation, and thus the columnar dipole moment, is receptive to geometric frustration if the columns aggregate in a hexagonal rod packing. The frustration suppresses conventional antiferroelectric order and heightens the sensitivity towards collective intercolumnar packing effects. The latter finding allows for the building up of mesoscale domains with spontaneous polarization. Our results suggest how the complex interplay between steric and electrostatic interactions is influenced by a straightforward chemical design of the molecular synthons to create spontaneous polarization and to adjust mesoscale domain size.

With regard to upcoming regulations of common chemical blowing agents for epoxy foams, carbamates provide suitable alternatives. They act as blowing agents releasing CO 2 and cure epoxy resins after decomposition and amine release. Thus, no undesired byproducts occur. In this study, a detailed analysis of the chemical structures, the decomposition, and the curing behavior of the carbamates received from N-aminoethylpiperazine (B-AEP), 4methylcyclohexane-1,3-diamine (B-DMC), and isophorone diamine (B-IPDA) was attempted. The carbamates were finally used for foaming of diglycidylether of bisphenol-A (DGEBA)-based epoxy resins at different temperatures. By this, the performance of the carbamates in a foaming experiment could be qualitatively compared. The results show that all carbamates are suitable for foaming at specifically adapted temperatures. While B-DMC is able to foam properly only at 80 °C, B-IPDA requires 100−120 °C, and B-AEP is best used for foaming in the range between 120 and 140 °C.

Controlling the solid-state morphology of semiconducting polymers is crucial for the function and performance of optoelectronic and photonic devices. Nucleation is a commonly used and straightforward approach to tailor the solid-state morphology of semi-crystalline polymers. However, efficient nucleating agents for semiconducting polymers are still rare. Here, we present a conceptual approach to tailor supramolecular nucleating agents for the semiconducting polymer, poly(3-hexylthiophene) (P3HT). Using this approach, we developed a class of supramolecular nucleating agents, which can achieve outstanding nucleation efficiencies of more than 95% at concentrations as low as 0.1 wt %. Such efficiencies can be achieved by combining an exceptionally high epitaxial match with highly regularly arranged donor−acceptor interactions between the nucleating agent and the polymer. Notably, the supramolecular agents do not induce trap states in thin films of P3HT and are beneficial for the film stability by controlling the solid-state morphology. We anticipate that this approach can be transferred to other semi-crystalline conjugated polymers, resulting in defined solid-state morphologies.

The efficiency of dynamic nuclear polarization (DNP) enhanced 19F MAS NMR spectroscopy without 19F-containing solvents and matrices, which transport polarization via 19F–19F spin diffusion, is demonstrated. By preventing solvent and matrix signals respectively masking the corresponding resonances, this enables the detection of fluorinated target molecules in nanomolar amounts. As model compound, 1,3,5-tris­(2-fluoro-2-methylpropionylamino)­benzene (F-BTA) is investigated in a frozen 1,1,2,2-tetrachloroethane (TCE) solution and incorporated into a matrix of isotactic polypropylene (i-PP). While the polarizing agent is homogeneously dissolved within the frozen solution, for the i-PP/F-BTA blend, it is distributed via the incipient wetness impregnation (IWI) technique. For the frozen solutions with an F-BTA concentration of 187.5 mM an εon/off of 260 was obtained. For F-BTA concentrations of 10 and 2.5 mM the sensitivity trend suggests even higher DNP gains. The substantial enhancements could be achieved by direct polarization transfer over distances up to at least 20 Å, derived from a simple geometric model assuming a homogeneous solution, engaging a large part of the sample volume. Cross-polarization (CP) to 13C nuclei allowed selection of the NMR spectroscopic resonances of the minority species in the i-PP/F-BTA blend suppressing the otherwise dominating resonances of the IWI solvent and the polymer matrix. The possibility of exciting 19F via DNP directly and of transferring the polarization to other heteronuclei within close proximity enables spatial spectral editing to clear up spectra otherwise crowded by matrix and solvent signals. We thus expect direct polarization transfer techniques for DNP enhanced NMR spectroscopy to become more important in the future.

Polystyrene foams have become more and more important owing to their lightweight potential and their insulation properties. Progress in this field is expected to be realized by foams featuring a microcellular morphology. However, large-scale processing of low-density foams with a closed-cell structure and volume expansion ratio of larger than 10, exhibiting a homogenous morphology with a mean cell size of approximately 10 µm, remains challenging. Here, we report on a series of 4,4′-diphenylmethane substituted bisamides, which we refer to as kinked bisamides, acting as efficient supramolecular foam cell nucleating agents for polystyrene. Self-assembly experiments from solution showed that these bisamides form supramolecular fibrillary or ribbon-like nanoobjects. These kinked bisamides can be dissolved at elevated temperatures in a large concentration range, forming dispersed nano-objects upon cooling. Batch foaming experiments using 1.0 wt.% of a selected kinked bisamide revealed that the mean cell size can be as low as 3.5 µm. To demonstrate the applicability of kinked bisamides in a high-throughput continuous foam process, we performed foam extrusion. Using 0.5 wt.% of a kinked bisamide yielded polymer foams with a foam density of 71 kg/m3 and a homogeneous microcellular morphology with cell sizes of ≈10 µm, which is two orders of magnitude lower compared to the neat polystyrene reference foam with a comparable foam density.