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Electrospinning was employed to synthesize a Ag nanoparticle (NP)-impregnated partially aligned and free-standing carbon nanofibers (CNFs) mat using a polyacrylonitrile (PAN) and silver nitrate blend followed by carbonization. Pyrolyzation of the PAN/AgNO 3 blend produced the nanoporous CNFs, and the Ag NPs were grown within the CNFs via thermal decomposition of AgNO 3 . The fiber diameters of the synthesized CNFs ranged from 130 to 190 nm, and the size of the impregnated Ag NPs was ∼30 nm. The presence of the Ag NPs enhanced the electrical conductivity and promoted graphitization of the CNFs via the templating effect of the Ag NPs. These synthesized CNFs and AgCNFs nanocomposite were electrophoretically deposited onto indium tin oxide electrodes for detection of triglyceride molecules. Oxygen plasma treatment of the CNFs and AgCNFs surfaces resulted in enhanced loading of lipase and glycerol dehydrogenase bienzymes. The AgCNFs nanocomposite exhibited faster electron transfer than the CNFs, as corroborated by electrochemical impedance spectroscopy and cyclic voltammetry studies. Covalent functionalization via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/ N -hydroxysuccinimide coupling chemistry on a nanoporous CNFs surface led to higher stability of the fabricated biosensor toward triglyceride detection. The sensitivity was four-fold higher for the AgCNFs (1.232 μA mg/dL −1 cm −2 ) bioelectrode compared with the CNFs (0.33 μA mg/dL −1 cm −2 ) over a wide detection range (25–500 mg/dL). These biosensors exhibited excellent selectivity, good reproducibility, and faster response (10 s). Thus, enhanced graphitization and electrical conductivity of nanoporous CNFs via incorporation of Ag NPs yields a promising platform for the detection of triglyceride (TG) biomolecules. [ABSTRACT FROM AUTHOR]

We present a straightforward method for fabricating functional micro-, submicro-, and nano-channels embedded in a porous carbon film and the application of this microfluidic platform for electrochemical sensing. A skin layer of poly(methyl methacrylate) (PMMA) fibers was first electrospun on a thoroughly cleaned Si wafer substrate, followed by spin coating of a polyacrylonitrile (PAN) film on top of the skin. High-temperature carbonization of the composite film decomposed the PMMA fibers and produced embedded microchannels in the PAN-derived amorphous monolithic carbon electrode. The channels were decorated with Pt nanoparticles by in situ thermal decomposition of a precursor metal salt to enhance functionality of the carbon electrode. Carbon electrodes decorated with Pt nanoparticles (carbon-Pt), with and without embedded microchannels, were used to detect the food toxin aflatoxin B1 (AFB1) by surface biofunctionalization with the antibodies of AFB1 (anti-AFB1) via an electrochemical impedance technique. The aligned nanochannels in the porous carbon film act as a reaction chamber for antigen–antibody interactions and provide channels for fast electron transport toward the electrode from the electrolyte, resulting in improved electrochemical performance of the biosensor. The fabricated immunosensor is highly sensitive to 1 pg/mL of AFB1 with a concentration range of 10 −12 –10 −7 g/mL. [ABSTRACT FROM AUTHOR]

This paper reports a combined experimental-modeling study on the adhesion at glass/poly(vinyl butyral) (PVB) interfaces. PVB is a critical component in laminated glasses that provides impact resistance and prevents spallation in the event of glass breakage. We characterize the mode I (normal) and mode II (shear) interfacial fracture behaviors in glass/PVB/glass laminates and obtained independent cohesive (traction–separation) laws for the two modes. We observe a pronounced rate dependence of both traction-separation laws. Specifically, with increasing loading rate, the interfacial stiffness, the peak stress, and the fracture toughness increase while the critical opening or shear displacement decreases. These measured traction-separation laws are used as inputs in finite element analysis to predict the mechanical behavior of the peel test, which agrees reasonably well with the experimental results. Finite element analysis of a glass laminate subjected to impact loading demonstrates how the measured interfacial properties can be used to predict the mechanical behavior and failure of laminated glass. [ABSTRACT FROM AUTHOR]

With the technological advancement in micro-electro-mechanical systems (MEMS), microfabrication processes along with digital electronics together have opened novel avenues to the development of small-scale smart sensing devices with improved sensitivity with a lower cost of fabrication and relatively small power consumption. This article aims to provide the overview of the recent work carried out on the fabrication methodologies adopted to develop silicon based resonant sensors. A detailed discussion has been carried out to understand critical steps involved in the fabrication of the silicon-based MEMS resonator. Some challenges starting from the materials' selection to the final phase of obtaining a compact MEMS resonator device for its fabrication have also been explored critically. [ABSTRACT FROM AUTHOR]

Highlights: [•] One step synthesis of macroporous polymer and carbon sub-micron films by spin coating. [•] Dewetting produces films with hole density in the range of 108–109 percm2. [•] Composite carbon/nanoparticle films compatible with roll-to-roll processing. [•] Catalytic conversion of para-nitrophenol to para-aminophenol by Ag/carbon composite. [Copyright &y& Elsevier]

Wearable electronic devices (WEDs) are receiving significant attention because of the increasing interest in soft robotics, electronic skin, and wearable sensors. Liquid metals (LMs) are compelling for WEDs owing to their metallic conductivity, fluidic nature, and low toxicity. Herein, we fabricated stretchable and soft WEDs using LM (eutectic gallium-indium alloy) wires (LMWs) patterned via force wetting through custom-made stencils on an elastic substrate. LMWs can generate thermal energy via Joule heating upon current application and deliver it to the substrate, resulting in wearable polymeric heaters. The LM mixed with carbonyl iron particles (CIPs) can also be patterned while preserving fluidic behavior. The degree of thermal energy generated through the LMWs can be manipulated as a function of the CIP concentration in the LM and geometrical factors of the electrode patterns, i.e., width and length. An elastic film patterned with LMWs attached to the human body exhibits changes in the effective electrical resistance depending on applied strain, demonstrating potential as a wearable strain sensor. This LM utilized WED that can generate thermal energy upon current application through the LMWs and detect the bodily motion has significant potential for application in wearable thermotherapy, electronic skin, and soft sensors. [Display omitted] • Soft and stretchable wearable heaters and strain sensors utilizing liquid metal electrode. • Wearable devices exhibiting ultrasoftness (116 kPa), ultrastretchability (>1300 %) and strong adhesion to the surfaces. • Wearable devices exhibiting ultrasoftness (Young's modulus of 116 kPa), ultrastretchability (elongation at break of > 1300 %) and strong adhesion to the surfaces. • Wearable devices generating thermal energy by Joule-heating through liquid metal wires. • Liquid metal wires changing electrical resistance by deformation upon strain. [ABSTRACT FROM AUTHOR]