Functionalized Amphiphilic Block Copolymers and Complex Emulsions for Selective Sensing of Dissolved Metals at Liquid-Liquid Interfaces.

Increasing contamination in potable water supplies necessitates the development of sensing methods that provide the speed and selectivity necessary for safety. One promising method relies on recognition and detection at the liquid-liquid interface of dynamic complex emulsions. These all-liquid materials transduce changes in interfacial tensions into optical signals via the coupling of their chemical, physical, and optical properties.

Multiplexed and continuous microfluidic sensors using dynamic complex droplets.

Emissive complex droplets with reconfigurable morphology and dynamic optical properties offer exciting opportunities as chemical sensors due to their stimuli-responsive characteristics. In this work, we demonstrated a real-time optical sensing platform that combines poly(dimethylsiloxane) (PDMS) microfluidics and complex droplets as sensing materials. We utilized a mechanism, called directional emission, to transduce changes in interfacial tension into optical signals.

Detection of PFAS and Fluorinated Surfactants Using Differential Behaviors at Interfaces of Complex Droplets.

Contamination of per- and polyfluoroalkyl substances (PFAS) in water supplies will continue to have serious health and environmental consequences. Despite the importance of monitoring the concentrations of PFAS at potential sites of contamination and at treatment plants, there are few suitable and rapid on-site methods. Many nonconventional techniques do not possess the necessary selectivity and sensitivity to distinguish PFAS from other surface-active components and to quantify the low concentrations in real-world conditions.

Rapid Detection of Sepsis: Recent Advances in Biomarker Sensing Platforms.

Sepsis is a major cause of mortality among hospitalized patients worldwide. Rapid diagnosis is critical as early treatments have been demonstrated to improve survival. Despite the importance of early detection, current technologies and clinical methods are often insufficient due to their lack of the necessary speed, selectivity, or sensitivity.

Fluorescent Janus emulsions for biosensing of .

Here we report a sensing method for based on the agglutination of all-liquid Janus emulsions. This two-dye assay enables the rapid detection of trace in less than 2 h via an emissive signal produced in response to binding. The biorecognition interface between the Janus emulsions is assembled by attaching antibodies to a functional surfactant polymer with a tetrazine/transcyclooctene click reaction.

Precision pH Sensor Based on WO Nanofiber-Polymer Composites and Differential Amplification.

We report a new type of potentiometric pH sensor with sensitivity exceeding the theoretical Nernstian behavior (-59.1 mV/pH). For the pH-sensitive electrode, 1D tungsten oxide (WO) nanofibers (NFs) were prepared to obtain large surface area and high porosity.

Chemiresistive Sensor Array and Machine Learning Classification of Food.

Successful identification of complex odors by sensor arrays remains a challenging problem. Herein, we report robust, category-specific multiclass-time series classification using an array of 20 carbon nanotube-based chemical sensors. We differentiate between samples of cheese, liquor, and edible oil based on their odor.

Rapid Detection of via Directional Emission from Carbohydrate-Functionalized Dynamic Double Emulsions.

Reliable early-stage detection of foodborne pathogens is a global public health challenge that requires new and improved sensing strategies. Here, we demonstrate that dynamically reconfigurable fluorescent double emulsions can function as highly responsive optical sensors for the rapid detection of carbohydrates fructose, glucose, mannose, and mannan, which are involved in many biological and pathogenic phenomena. The proposed detection strategy relies on reversible reactions between boronic acid surfactants and carbohydrates at the hydrocarbon/water interface leading to a dynamic reconfiguration of the droplet morphology, which alters the angular distribution of the droplet's fluorescent light emission.

Janus Graphene: Scalable Self-Assembly and Solution-Phase Orthogonal Functionalization.

Orthogonal functionalization of 2D materials by selective assembly at interfaces provides opportunities to create new materials with transformative properties. Challenges remain in realizing controllable, scalable surface-selective, and orthogonal functionalization. Herein, dynamic covalent assembly is reported that directs the functionalization of graphene surfaces at liquid-liquid interfaces.

Stretchable and Degradable Semiconducting Block Copolymers.

This paper describes the synthesis and characterization of a class of highly stretchable and degradable semiconducting polymers. These materials are multi-block copolymers (BCPs) in which the semiconducting blocks are based on the diketopyrrolopyrrole (DPP) unit flanked by furan rings and the insulating blocks are poly(ε-caprolactone) (PCL). The combination of stiff conjugated segments with flexible aliphatic polyesters produces materials that can be stretched >100%.

Waveguide-based chemo- and biosensors: complex emulsions for the detection of caffeine and proteins.

We report on a new modular sensing approach in which complex emulsions serve as efficient transducers in optical evanescent field-based sensing devices. Specifically, we leverage the tunable refractive index upon chemically triggered changes in droplet morphology or orientation. Variations in the optical coupling result in readily detectable changes in the light transmitted from a waveguide.

Effects of flexibility and branching of side chains on the mechanical properties of low-bandgap conjugated polymers.

This paper describes effects of the flexibility, length, and branching of side chains on the mechanical properties of low-bandgap semiconducting polymers. The backbones of the polymer chains comprise a diketopyrrolopyrrole (DPP) motif flanked by two furan rings and copolymerized by Stille polycondensation with thiophene (DPP2FT). The side chains of the DPP fall into three categories: linear alkyl (C8, C14, or C16), branched alkyl (ethylhexyl, EH, or hexyldecyl, HD), and linear oligo(ethylene oxide) (EO3, EO4, or EO5).

Morphology-Dependent Luminescence in Complex Liquid Colloids.

Complex liquid colloids hold great promise as transducers in sensing applications as a result of their tunable morphology and intrinsic optical properties. Herein, we introduce meta-amino substituted green fluorescence protein chromophore (GFPc) surfactants that localize at the organic-water interface of complex multiphase liquid colloids. The meta-amino GFPc exhibits hydrogen-bonding (HB) mediated fluorescence quenching, and are nearly nonemissive in the presence of protic solvents.

Modular Synthesis of Polymers Containing 2,5-di(thiophenyl)-N-arylpyrrole.

A modular facile route has been developed to synthesize functionalized 2,5-di(thiophen-2-yl)-1-H-arylpyrroles from readily available starting materials. These units are compatible with various polymerization conditions and are versatile building blocks for conjugated polymers. The polymers show high thermal stability and solubility in a number of solvents.

Carbon Nanotube Chemical Sensors.

Carbon nanotubes (CNTs) promise to advance a number of real-world technologies. Of these applications, they are particularly attractive for uses in chemical sensors for environmental and health monitoring. However, chemical sensors based on CNTs are often lacking in selectivity, and the elucidation of their sensing mechanisms remains challenging.

Insights into Magneto-Optics of Helical Conjugated Polymers.

Materials with magneto-optic (MO) properties have enabled critical fiber-optic applications and highly sensitive magnetic field sensors. While traditional MO materials are inorganic in nature, new generations of MO materials based on organic semiconducting polymers could allow increased versatility for device architectures, manufacturing options, and flexible mechanics. However, the origin of MO activity in semiconducting polymers is far from understood.

Bio-Inspired Carbon Monoxide Sensors with Voltage-Activated Sensitivity.

Carbon monoxide (CO) outcompetes oxygen when binding to the iron center of hemeproteins, leading to a reduction in blood oxygen level and acute poisoning. Harvesting the strong specific interaction between CO and the iron porphyrin provides a highly selective and customizable sensor. We report the development of chemiresistive sensors with voltage-activated sensitivity for the detection of CO comprising iron porphyrin and functionalized single-walled carbon nanotubes (F-SWCNTs).

Janus Emulsions for the Detection of Bacteria.

Janus emulsion assays that rely on carbohydrate-lectin binding for the detection of bacteria are described. Surfactants containing mannose are self-assembled at the surface of Janus droplets to produce particles with lectin binding sites. Janus droplets orient in a vertical direction as a result of the difference in densities between the hydrocarbon and fluorocarbon solvents.

Mechanical Properties of Organic Semiconductors for Stretchable, Highly Flexible, and Mechanically Robust Electronics.

Mechanical deformability underpins many of the advantages of organic semiconductors. The mechanical properties of these materials are, however, diverse, and the molecular characteristics that permit charge transport can render the materials stiff and brittle. This review is a comprehensive description of the molecular and morphological parameters that govern the mechanical properties of organic semiconductors.

Interfacial Polymerization on Dynamic Complex Colloids: Creating Stabilized Janus Droplets.

Complex emulsions, including Janus droplets, are becoming increasingly important in pharmaceuticals and medical diagnostics, the fabrication of microcapsules for drug delivery, chemical sensing, E-paper display technologies, and optics. Because fluid Janus droplets are often sensitive to external perturbation, such as unexpected changes in the concentration of the surfactants or surface-active biomolecules in the environment, stabilizing their morphology is critical for many real-world applications. To endow Janus droplets with resistance to external chemical perturbations, we demonstrate a general and robust method of creating polymeric hemispherical shells via interfacial free-radical polymerization on the Janus droplets.

Effect of Broken Conjugation on the Stretchability of Semiconducting Polymers.

Increasing the flexibility of polymer chains is a common method of increasing the deformability of solid polymeric materials. Here, the effects of "conjugation-break spacers" (CBSs)-aliphatic units that interrupt the sp -hybridized backbone of semiconducting polymers-on the mechanical and photovoltaic properties of a diketopyrrolopyrrole-based polymer are described. Unexpectedly, the tensile moduli and cracking behavior of a series of polymers with repeat units bearing 0%, 30%, 50%, 70%, and 100% of the CBS are not directly related to the percent incorporation of the flexible unit.

Mechanical Properties of Solution-Processed Small-Molecule Semiconductor Films.

Advantages of semiconducting small molecules-as opposed to semiconducting polymers-include synthetic simplicity, monodispersity, low cost, and ease of purification. One purported disadvantage of small-molecule films is reduced mechanical robustness. This paper measures the tensile modulus and crack-onset strain for pure films of the high-performance solution-processable small-molecule donors 7,7'-[4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl]bis[6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazole] (DTS(FBTTh2)2), 2,5-di(2-ethylhexyl)-3,6-bis(5″-n-hexyl-[2,2',5',2″]terthiophen-5-yl)-pyrrolo[3,4-c]pyrrole-1,4-dione (SMDPPEH), and 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene), the acceptor 5,5'-(2,1,3-benzothiadiazole-4,7-diyldi-2,1-ethenediyl)bis[2-hexyl-1H-isoindole-1,3(2H)-dione] (HPI-BT), blends of DTS(FBTTh2)2 and SMDPPEH with [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) and with HPI-BT, and bulk heterojunction films processed with the additives 1,8-diiodooctane (DIO) and polystyrene (PS).

Yield Point of Semiconducting Polymer Films on Stretchable Substrates Determined by Onset of Buckling.

Mechanical buckling of thin films on elastomeric substrates is often used to determine the mechanical properties of polymers whose scarcity precludes obtaining a stress-strain curve. Although the modulus and crack-onset strain can readily be obtained by such film-on-elastomer systems, information critical to the development of flexible, stretchable, and mechanically robust electronics (i.e.

Metal-assisted exfoliation (MAE): green, roll-to-roll compatible method for transferring graphene to flexible substrates.

Graphene is expected to play a significant role in future technologies that span a range from consumer electronics, to devices for the conversion and storage of energy, to conformable biomedical devices for healthcare. To realize these applications, however, a low-cost method of synthesizing large areas of high-quality graphene is required. Currently, the only method to generate large-area single-layer graphene that is compatible with roll-to-roll manufacturing destroys approximately 300 kg of copper foil (thickness = 25 μm) for every 1 g of graphene produced.