7 research outputs found
Crystal Engineering of Supramolecular 1,4-Benzene Bisamides by Side-Chain Modification : Towards Tuneable Anisotropic Morphologies and Surfaces
Benzene bisamides are promising building blocks for supramolecular nanoâobjects. Their functionality depends on morphology and surface properties. However, a direct link between surface properties and molecular structure itself is missing for this material class. Here, we investigate this interplay for two series of 1,4âbenzene bisamides with symmetric and asymmetric peripheral substitution. We elucidated the crystal structures, determined the nanoâobject morphologies and derived the wetting behaviour of the preferentially exposed surfaces. The crystal structures were solved by combining singleâcrystal and powder Xâray diffraction, solidâstate NMR spectroscopy and computational modelling. Bulky side groups, here tâbutyl groups, serve as a structureâdirecting motif into a packing pattern, which favours the formation of thin platelets. The use of slim peripheral groups on both sides, in our case linear perfluorinated, alkyl chains, selfâassemble the benzene bisamides into a second packing pattern which leads to ribbonâlike nanoâobjects. For both packing types, the preferentially exposed surfaces consist of the ends of the peripheral groups. Asymmetric substitution with bulky and slim groups leads to an ordered alternating arrangement of the groups exposed to the surface. This allows the hydrophobicity of the surfaces to be gradually altered. We thus identified two leitmotifs for molecular packings of benzene bisamides providing the missing link between the molecular structure, the anisotropic morphologies and adjustable surface properties of the supramolecular nanoâobjects
Highly Efficient Supramolecular Nucleating Agents for Poly(3-hexylthiophene)
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
CCDC 2103040: Experimental Crystal Structure Determination
Related Article: Felix A. Wenzel, Hannes Welz, Kasper P. van der Zwan, Sebastian StĂ€ter, Klaus Kreger, Richard Hildner, JĂŒrgen Senker, Hans-Werner Schmid|2022|Macromolecules|55|2861|doi:10.1021/acs.macromol.1c0228