Titel Deelnemers "Korte inhoud" "Two-Leg Molecular Ladders Formed by Hierarchical Self-Assembly of an Organic Radical" "Chris Van Haesendonck, Mark Van der Auweraer, Steven De Feyter" "The supramolecular organization of a new polychlorotriphenyl (PTM) radical bearing three long alkyl chains has been studied by scanning tunneling microscopy (STM) at the liquid-solid interface. This radical hierarchically self-assembles on graphite forming head-to-head dimers that organize in rows following an interesting spin-containing two-leg molecular ladder topology, in which the alkyl chains determine the space between the radical rows and act as diamagnetic barriers. In addition, these double-rows also self-assemble three-dimensionally, leading to a multilayer organization which is still influenced by the HOPG substrate symmetry. The observed nanostructures are sustained by different intermolecular interactions such as Cl center dot center dot center dot Cl, Cl center dot center dot center dot Ph, pi-pi, van der Waals, and CH center dot center dot center dot pi interactions. Theoretical calculations were used to model the observed assemblies, and the results were in complete agreement with the experimental data. Remarkably, atomic force microscopy (AFM) studies confirmed that this tendency to form double rows composed by the PTM magnetic heads surrounded by the alkyl chains is maintained after the complete evaporation of the solvent. The electrochemical and magnetic properties of these PTM nanostructures were also demonstrated." "Hierarchical growth of curved organic nanowires upon evaporation induced self-assembly" "Steven De Feyter" "Self-assembly of a TTF derivative capable of forming self-assembled monolayers at the surface of graphite displays hierarchical growth of multilayers and concentric nanorings upon evaporation of the solvent as observed by AFM." "Engineering hierarchical nanostructures by elastocapillary self-assembly" "Michaël De Volder" "Surfaces coated with nanoscale filaments such as silicon nanowires and carbon nanotubes are potentially compelling for high-performance battery and capacitor electrodes, photovoltaics, electrical interconnects, substrates for engineered cell growth, dry adhesives, and other smart materials. However, many of these applications require a wet environment or involve wet processing during their synthesis. The capillary forces introduced by these wet environments can lead to undesirable aggregation of nanoscale filaments, but control of capillary forces can enable manipulation of the filaments into discrete aggregates and novel hierarchical structures. Recent studies suggest that the elastocapillary self-assembly of nanofilaments can be a versatile and scalable means to build complex and robust surface architectures. To enable a wider understanding and use of elastocapillary self-assembly as a fabrication technology, we give an overview of the underlying fundamentals and classify typical implementations and surface designs for nanowires, nanotubes, and nanopillars made from a wide variety of materials. Finally, we discuss exemplary applications and future opportunities to realize new engineered surfaces by the elastocapillary self-assembly of nanofilaments." "Hierarchical self-assembly of enantiopure and racemic helicenes at the liquid/solid interface: from 2D to 3D" "Hai Cao, Johannes Seibel, Deepali Waghray, Zhi Li, Kunal Mali, Wim Dehaen, Steven De Feyter" "The performance of organic nanostructures is closely related to the organization of the functional molecules. Frequently, molecular chirality plays a central role in the way molecules assemble at the supramolecular level. Herein we report the hierarchical self-assembly of benzo-fused tetrathia[7]helicenes on solid surfaces, from a single surface-bound molecule to well-defined microstructures, using a combination of various characterization techniques assisted by molecular modeling simulations. Similarities as well as discrepancies are revealed between homochiral and heterochiral aggregations by monitoring the hierarchical nucleation of helicenes on surfaces, where the impact of enantiopurity, concentration and adsorbate-substrate interaction on molecular organization are disclosed." "Hierarchical Self-Assembly of a Supramolecular Protein-Metal Cage Encapsulating a Polyoxometalate Guest" "Laurens Vandebroek, Luc Van Meervelt, Arnout Voet, Tatjana Vogt" "3D interconnected hierarchically macro-mesoporous $TiO_{2}$ networks optimized by biomolecular self-assembly for high performance lithium ion batteries" "Xiao-Ning Ren, Liang Wu, Jun Jin, Jing Liu, Zhiyi Hu, Yu Li, Tawfique Hasan, Xiao-Yu Yang, Staf Van Tendeloo, Bao-Lian Su" "Biomolecular self-assembly is an effective synthesis strategy for material fabrication with unique structural complexity and properties. For the first time, we integrate inner-particle mesoporosity in a three-dimensional (3D) interconnected macroporous TiO2 structure via the mediation of biomolecular self-assembly of the lipids and proteins from rape pollen coats and Pluronic P123 to optimize the structure for high performance lithium storage. Benefitting from the hierarchically 3D interconnected macro-mesoporous structure with high surface area, small nanocrystallites and good electrolyte permeation, such a unique porous structure demonstrates superior electrochemical performance, with high initial coulombic efficiency (94.4% at 1C) and a reversible discharge capacity of 161, 145, 127 and 97 mA h g−1 at 2, 5, 10 and 20C for 1000 cycles, with 79.3%, 89.9%, 90.1% and 87.4% capacity retention, respectively. Using SEM, TEM and HRTEM observations on the TiO2 materials before and after cycling, we verify that the inner-particle mesoporosity and the Li2Ti2O4 nanocrystallites formed during the cycling process in interconnected macroporous structure greatly enhance the cycle life and rate performance. Our demonstration here offers opportunities towards developing and optimizing hierarchically porous structures for energy storage applications via biomolecular self-assembly." "How Does Chemisorption Impact Physisorption? Molecular View of Defect Incorporation and Perturbation of Two-Dimensional Self-Assembly" "Brandon Hirsch, Peter Walke, Jeremy Harvey, Steven De Feyter" "© 2018 American Chemical Society. Chemical and structural defects in otherwise pristine materials can result in either an improved or degraded material performance. Unfortunately, little is known about the role of these defects in complex hierarchical processes, such as self-assembly. Here, the influence of defective surfaces on physisorbed self-assembly occurring at liquid/solid interfaces is investigated. Covalently bound defects on graphite surfaces are generated by electrochemically activating diazonium cations. After creating the defective substrates, a solution containing self-assembling molecules was deposited on the surface. Subsequent scanning probe investigations expose how the chemisorbed molecular units can either be incorporated within a porous hexagonal network, or generate local perturbations in the form of partial or full desorption of the physisorbed molecules. Overall, the chemisorbed molecules alter the local energy landscape for self-assembly to isolate new molecular packing arrangements. With a single-molecule perspective, this work outlines how chemical defects contribute to the formation of metastable assemblies and their evolutionary pathways toward higher-symmetry networks." "Fast Self-Assembly Dynamics of a β-Sheet Peptide Soft Material" "Jolien Bertouille, Sandor Kasas, Charlotte Martin, Ulrich Hennecke, Steven Ballet, Ronnie Willaert" "Peptide-based hydrogels are promising biocompatible materials for wound healing, drug delivery, and tissue engineering applications. The physical properties of these nanostructured materials depend strongly on the morphology of the gel network. However, the self-assembly mechanism of the peptides that leads to a distinct network morphology is still a subject of ongoing debate, since complete assembly pathways have not yet been resolved. To unravel the dynamics of the hierarchical self-assembly process of the model β-sheet forming peptide KFE8 (Ac-FKFEFKFE-NH2 ), high-speed atomic force microscopy (HS-AFM) in liquid is used. It is demonstrated that a fast-growing network, based on small fibrillar aggregates, is formed at a solid-liquid interface, while in bulk solution, a distinct, more prolonged nanotube network emerges from intermediate helical ribbons. Moreover, the transformation between these morphologies has been visualized. It is expected that this new in situ and in real-time methodology will set the path for the in-depth unravelling of the dynamics of other peptide-based self-assembled soft materials, as well as gaining advanced insights into the formation of fibers involved in protein misfolding diseases." "Self-assembly of poly(2-alkyl-2-oxazoline)s by crystallization in ethanol-water mixtures below the upper critical solution temperature" "Christina Diehl, Ina Dambowsky, Richard Hoogenboom, Helmut Schlaad" "Multifunctional Tricarbazolo Triazolophane Macrocycles: One-Pot Preparation, Anion Binding, and Hierarchical Self-Organization of Multilayers" "Brandon Hirsch" "Programming the synthesis and self-assembly of molecules is a compelling strategy for the bottom-up fabrication of ordered materials. To this end, shape-persistent macrocycles were designed with alternating carbazoles and triazoles to program a one-pot synthesis and to bind large anions. The macrocycles bind anions that were once considered too weak to be coordinated, such as PF6 (-) , with surprisingly high affinities (β2 =10(11)  M(-2) in 80:20 chloroform/methanol) and positive cooperativity, α=(4 K2 /K1 )=1200. We also discovered that the macrocycles assemble into ultrathin films of hierarchically ordered tubes on graphite surfaces. The remarkable surface-templated self-assembly properties, as was observed by using scanning tunneling microscopy, are attributed to the complementary pairing of alternating triazoles and carbazoles inscribed into both the co-facial and edge-sharing seams that exist between shape-persistent macrocycles. The multilayer assembly is also consistent with the high degree of molecular self-association observed in solution, with self-association constants of K=300 000 M(-1) (chloroform/methanol 80:20). Scanning tunneling microscopy data also showed that surface assemblies readily sequester iodide anions from solution, modulating their assembly. This multifunctional macrocycle provides a foundation for materials composed of hierarchically organized and nanotubular self-assemblies."