RESUMEN
Wearable electronics have the potential to advance personalized health care, alleviate disability, enhance communication, and improve homeland security. Development of multifunctional electronic textiles (e-textiles) with the capacity to interact with the local environment is a promising strategy for achieving electronic transduction of physical and chemical information. This paper describes a simple and rapid approach for fabricating multifunctional e-textiles by integrating conductive two-dimensional (2D) metal-organic frameworks (MOFs) into fabrics through direct solution-phase self-assembly from simple molecular building blocks. These e-textiles display reliable conductivity, enhanced porosity, flexibility, and stability to washing. The functional utility of these integrated systems is demonstrated in the context of chemiresistive gas sensing, uptake, and filtration. The self-organized frameworks on textiles (SOFT)-devices detect and differentiate important gaseous analytes (NO, H2S, and H2O) at ppm levels and maintain their chemiresistive function in the presence of humidity (5000 ppm, 18% RH). With sub-ppm theoretical limits of detection (LOD for NO = 0.16 ppm and for H2S = 0.23 ppm), these constitute the best textile-supported H2S and NO detectors reported and the best MOF-based chemiresistive sensors for these analytes. In addition to sensing, these devices are capable of capturing and filtering analytes.
RESUMEN
The synthetically tunable properties and intrinsic porosity of conductive metal-organic frameworks (MOFs) make them promising materials for transducing selective interactions with gaseous analytes in an electrically addressable platform. Consequently, conductive MOFs are valuable functional materials with high potential utility in chemical detection. The implementation of these materials, however, is limited by the available methods for device incorporation due to their poor solubility and moderate electrical conductivity. This manuscript describes a straightforward method for the integration of moderately conductive MOFs into chemiresistive sensors by mechanical abrasion. To improve electrical contacts, blends of MOFs with graphite were generated using a solvent-free ball-milling procedure. While most bulk powders of pure conductive MOFs were difficult to integrate into devices directly via mechanical abrasion, the compressed solid-state MOF/graphite blends were easily abraded onto the surface of paper substrates equipped with gold electrodes to generate functional sensors. This method was used to prepare an array of chemiresistors, from four conductive MOFs, capable of detecting and differentiating NH3, H2S and NO at parts-per-million concentrations.
RESUMEN
Supramolecular chemistry of conjugated and conformationally rigid arylene ethynylene macrocycles (AEMs) has been the subject of increasing recent interest. AEMs are suited to function as supramolecular building blocks and hosts for small molecular guests thanks to their well-defined, non-collapsible central cavities and the potential for long range ordering through intermolecular π-stacking. Their syntheses are highly modular--albeit typically lengthy--allowing access to a great structural variety of AEM candidates for applications as carbon-rich mesogens and ligands in liquid crystals, nanoporous solids, molecular electronics, and chemical sensors. In this perspective, we highlight our recent work on the inclusion complexes and porous materials constructed from AEMs. Through this prism, we reflect on the recent advances and the remaining challenges in the supramolecular chemistry of AEMs.
RESUMEN
The facile self-assembly of nanoscale boronate ester rectangles from linear bis-catechols and 1,4-benzene diboronic acid is described. Spectroscopic and computational analyses reveal the influence of extended π-conjugation on the rectangles' absorption and fluorescence properties. The rectangles represent a new class of discrete, organic soluble covalent organic polygons.