To date, crystallization studies conducted in space laboratories, which are prohibitively costly and unsuitable to most research laboratories, have shown the valuable effects of microgravity during ...crystal growth and morphogenesis. Herein, an easy and highly efficient method is shown to achieve space‐like experimentation conditions on Earth employing custom‐made microfluidic devices to fabricate 2D porous crystalline molecular frameworks. It is confirmed that experimentation under these simulated microgravity conditions has unprecedented effects on the orientation, compactness and crack‐free generation of 2D porous crystalline molecular frameworks as well as in their integration and crystal morphogenesis. It is believed that this work will provide a new “playground” to chemists, physicists, and materials scientists that desire to process unprecedented 2D functional materials and devices.
How to achieve simulated microgravity conditions on Earth? The art of growing and processing 2D porous crystalline molecular frameworks in simulated microgravity is presented.
•Role of interstitial solvent molecules and ultrasound in the delamination of 2D-CPs.•Ultrasound assisted synthesis of 2D coordination polymers.•Influence of the sonication time in the final ...delamination product.•Catalytic activity of nanosheets obtained by ultrasound assisted delamination.
Large blue rectangular crystals of the 2D layered coordination polymer 1 have been obtained. The interest for this complex is two-fold. First, complex 1 is made of 2D layers packing along the (0–11) direction favored by the presence of lattice and coordinated water molecules. And second, nanostructures that could be derived by delamination are potentially suitable for catalytic purposes. Therefore it represents an excellent example to study the role of interlayer solvent molecules on the ultrasound-assisted delamination of functionally-active 2D metal-organic frameworks in water, a field of growing interest. With this aim, ultrasound-assisted delamination of the crystals was optimized with time, leading to stable nanosheet colloidal water suspensions with very homogeneous dimensions. Alternative bottom-up synthesis of related nanocrystals under ultrasound sonication yielded similar shaped crystals with much higher size dispersions. Finally, experimental results evidence that the nanostructures have higher catalytic activities in comparison to their bulk counterparts, due to larger metallic center exposition. These outcomes confirm that the combination of liquid phase exfoliation and a suitable synthetic design of 2D coordination polymers represents a very fruitful approach for the synthesis of functional nanosheets with an enhancement of catalytic active sites, and in general, with boosted functional properties.
•Combined ultrasound and solvent assisted synthesis of 2D coordination polymers.•Role of interstitial solvent molecules in the delamination of 2D-CPs.•Influence of the sonication time in delamination ...and nanostructuration processes.•Morphological and supramolecular transformations in 2D-CPs.
Herein, a new 2-dimensional coordination polymer based on copper (II), {Cu2(L)(DMF)2}n, where L stands for 1,2,4,5-benzenetetracarboxylate (complex 1) is synthesized. Interestingly, we demonstrate that both solvent and sonication are relevant in the top-down fabrication of nanostructures. Water molecules are intercalated in suspended crystals of complex 1 modifying not only the coordination sphere of Cu(II) ions but also the final chemical formula and crystalline structure obtaining {Cu(L)(H2O)3·H2O}n (complex 2). On the other hand, ultrasound is required to induce the nanostructuration. Remarkably, different morphologies are obtained using different solvents and interconversion from one morphology to another seems to occur upon solvent exchange. Both complexes 1 and 2, as well as the corresponding nanostructures, have been fully characterized by different means such as infrared spectroscopy, x-ray diffraction and microscopy.
•Use of active metal ions/triphenylene ligands for the fabrication of MOFs and COFs.•Conductive properties.•2D materials.•Synthesis approaches towards control grain boundaries and crystal ...anisotropy.•Emerging devices.
Triphenylene (TP) based materials have experienced a great expansion in the latest years. TP molecules have interesting optoelectronic properties, arising from the aromatic core, which have been exploited in functional two-dimensional (2D) Metal-Organic Frameworks (MOFs) and Covalent Organic Frameworks (COFs) aside other organic polymers. In this review we summarize synthetic approaches of TP-based 2D MOFs and COFs emphasizing on the resulting morphology, crystalline domains and orientation, proven to have great impact on the properties and performance of these materials in functional devices. Specifically, we report a detailed description on the different TP-based 2D structures detailing the influence of the chemical and crystalline structure on the electronic properties, specially the in-plane and out-of-plane contribution to the electrical conductivity. Finally, we give also attention and present several examples of functional devices made out with these electronic materials with great impact in the literature as well as in future technological applications.
Electronic skins (e-skins), composed of various flexible sensors, mimic the sensing functions of human skin aiming for both healthcare monitoring and prosthetics development applications. So far ...different multi-component e-skin devices aimed to fulfill different requirements (biocompatibility, skin adhesion, flexibility, conductivity, sensitivity towards biological stimuli and stretchability) have been reported. However, the obtaining of such devices combining all the above requirements within a single material that simplifies not only cost but specially functioning still remains a challenge. For this, catechol-based materials have attracted special attention due to their adhesive properties, compatibility and melanin-like electrical conduction. In this work, 2,3,6,7,10,11 – hexahydroxy triphenylene (HHTP) was used as catechol moiety in a typical melanin-like polymerization, resulting in a free-standing melanin-inspired film (MN-film). The obtained MN-film showcased good conductivities with dual charge carriers (electrons and ions) under different environments, i.e. pure water and buffers simulating sweat. Large biocompatibility, adhesion and conformability to skin were obtained as well, allowing to implement the film in wearable electronic on-skin devices on porcine skin. Measurements in wearable devices indicated large sensitivity towards different stimuli (strain, motion and temperature) under sweat-like conditions.
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•Melanin-like free-standing films have been successfully designed and synthesized.•Films showcase large conductivities and adhesion to ex-vivo and human skin.•E-skin devices with the films show sensitivity to sweat, motion and temperature.
Microgravity has proved to be an ideal condition to grow crystals. In article number 2101777, Raphael Pfattner, Tiago Sotto Mayor, Daniel Ruiz‐Molina, Josep Puigmartí‐Luis, and co‐workers demonstrate ...how to generate simulated microgravity on Earth to grow 2D porous crystalline molecular frameworks such as 2D metal–organic frameworks and 2D covalent organic frameworks.
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