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, HS, and HO) 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 HS = 0.23 ppm), these constitute the best textile-supported HS 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.

Characterization of MOFs and full devices. Comprehensive sensing data and variance (PDF).

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.

The vibrational characteristics of 28 different boronic acid, boroxine anhydride, and boronate ester species have been systematically investigated using a combination of experimental infrared (IR) spectroscopy and computational modeling. IR bands characteristic to each boron-containing functionality have been categorized and assigned in conjunction with density functional theory (B3LYP/6-31G­(d)), with the aim of better understanding and distinguishing the vibrational characteristics of covalent organic frameworks (COFs) built from boronic acids. In several cases, vibrational assignments differ from those previously reported in the literature on boronic acid-based COFs. Vibrations commonly regarded as diagnostic for one functionality are found in regions of the IR spectrum where other functionalities also show characteristic peaks. The collective experimental and computational results reveal that several alternative bands in the IR region can be used to more diagnostically distinguish between boronic acid, boroxine anhydride, and boronate ester species. The results presented herein provide the tools for straightforward characterization of boroxine anhydride and boronate ester species using IR spectroscopy. The results can be applied to additional theoretical studies of larger COF-like assemblies as well as the analysis of other boronic-acid-based materials.

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γ-Cyclodextrin can assemble in the presence of KOH or RbOH into metal–organic frameworks (CD–MOFs) with applications in gas adsorption and environmental remediation. Crystalline CD–MOFs are grown by vapor diffusion and their reversible adsorption of CO2(g) is analyzed both qualitatively and quantitatively. The experiment can be tailored to high school through advanced undergraduate laboratories and engages students in several areas of fundamental chemistry (crystallization, chemical equilibria, acid–base reactions, gas laws), advanced materials (MOFs), and broader impacts of chemistry (renewable resources and environmental chemistry).

Polycyclic aromatic hydrocarbons (PAHs) are used as adhesives that can be removed on-demand by sublimation without application of solvent or mechanical force. These adhesives are polycrystalline solids that enable bonding of glass, metal, and plastic with lap shear forces ranging from 5 to 50 N cm −2 . Systematic examination of factors governing bonding suggests that favorable chemical interactions between bonded surfaces and PAHs, and structural features at the surface of the substrate influence both the lap shear force and the mechanism of failure. Utilizing sublimable PAHs enables sequential bonding and release of substrates, as well as control of actuation of electronic systems through mechanical work.

Six variably functionalized phenanthrene‐based bis(catechol) derivatives have been synthesized and their ability to undergo dynamic covalent assembly with 1,4‐benzenediboronic acid (BDBA) to give discrete, shape‐persistent [2+2] assemblies has been investigated. Systematically varying the functionality of the bis(catechol) derivatives is found to influence both the reaction conditions necessary to promote their self‐assembly with BDBA as well as the stability of the resulting assemblies in the presence of protic solvents. A model is proposed to describe how solvent choice and starting material functionality must be carefully balanced in order to shift many competing equilibria toward the formation of discrete, soluble covalent organic polygons. The results are expected to provide additional insight into optimizing the synthesis of other boronate ester polygons/polyhedra as well as related, “infinite” covalent organic frameworks (COFs).