We present the electrical transport control of conductive nanocomposites by in-situ generated hierarchically structured silver nanosatellite (AgNS) particles [1, 2]. The AgNS particles are synthesized by the in-situ etching and reduction reaction of Ag flakes embedded in matrix polymer [1, 2]. The etching is controlled by THF peroxide, resulting in an interparticle distance of 4.37 nm. The strain-invariant resistance is obtained over 30 % strain if the barrier height is negligible by matching the work function of silver and electron affinity of polymer (electrode application) [1]. In contrast, transport is changed to quantum tunneling if the barrier height is gradually increased by employing different matrix polymers with smaller electron affinities. In such case, strain-sensitive resistance change is obtained for sensor application [1]. The recent progress in our laboratory will also be introduced. References [1] Science Advances, 8(32), eabn3365. [2] Nature Communications, 11, 2252.

The importance of wearable devices increases steadily as they can provide realtime physical feedback, posses versatile functionality, and the best of all, a decent comfort to the wearer. While different kinds of actuators, such as motor driven tendon, pneumatics, and electromagnetic, t were applied to wearable devices, they all require rigid and bulky system attached to the wearer which can cause discomfort. Shape memory alloy (SMA) that can change its physical shape and stiffness by temperature change can be used as a wearable actuator, especially when SMA wires are processed into fabrics. Here, we developed SMA fabric which was prepared by knotting the SMA wires and expanding them into 2D fabrics. Also, the knotted SMA fabric was designed to have auxetic property which can dedicate to increasing compliance of wearable SMA fabric to the 3D-curved human body. Knotted auxetic-SMA fabric was successfully applied as a wearable haptic to deliver thermomechanical feedback to the wearer.

Continuous production of cost-effective and high-strength nanocellulose long filaments (NCLFs) is critical in the field of natural fiber-reinforced polymer composites (NFRPCs).Herein, we present an integrated wet-spinning system that incorporates a few previously researched filament production processes with the goal of mass fabrication of strong and tough continuous NCLFs.The spinning speed, bobbin winder speed, and NCLF drying conditions were experimentally optimized. The efficacy of the designed wet-spinning system was evaluated by its sustainability in delivering continuous NCLFs for an hour or longer without any interruptions.The two significant parameters considered for calibrating the integrated wet-spinning system are the mechanical characteristics and morphology of the fabricated NCLFs.The study has also incorporated external alignment techniques such as electric field and mechanical stretching of NCLFs to demonstrate the versatility of the designed integrated spinning system.

Depleting fossil fuels and environmental concerns have emphasized the necessity for more sustainable resources for high-performance structural applications. High strength, lightweight, and abundant bioresources make cellulose long filaments (CLFs) an excellent reinforcement for high-performance structural applications. At the same time, high strength and thermally stable vanillin epoxy can efficiently replace petroleum-based epoxies. This study introduces the combination of unidirectional CLFs and vanillin epoxy by using vacuum-assisted resin transfer molding for novel biobased composites. Owing to the low density of CLFs, the proposed composite material possessed very low density, high specific flexural strength, and excellent thermal and hydrophobic properties. The FTIR analysis demonstrated good interfacial adhesion between CLFs and vanillin epoxy. The sustainable resources, hydrophobicity, and good mechanical performance make unidirectional CLFs reinforced Vanillin epoxy composite an excellent candidate for high-performance structural applications.

Condition-based monitoring has emerged as one of the important monitoring tools in power plants to continuously supply high-quality power. This paper, we describe a monitoring mechanism for high-voltage electrical equipment using thermal imaging with the aim of detecting faults in the power system in advance and reducing losses.

Piezoelectric ceramics, lead zirconate titanate (PZT), have been widely used for sensors and actuators due to their high electromechanical properties. However, the brittle nature of ceramics limits their applications to only small deformations as the flexibility and durability of these materials are the main essential factors required for practical applications. The flexible piezoelectric materials can be developed by blending PZT with flexible polymeric materials such as nanocellulose fibers. The bio-based nanocellulose fibers (CNF) have been reported as a type of electroactive polymer with a piezoelectric response exhibiting excellent mechanical strength and modulus. In this regard, the present study focuses on enhancing the mechanical strength and load-bearing capability of PZT by blending 20 and 30wt% of PZT powder with 80 and 70wt% CNF to obtain a flexible piezoelectric composite film via 3D printing. The 3D printed films' structural, morphological, and mechanical properties were investigated through XRD, SEM, and tensile tests. The SEM images and XRD analysis demonstrated that the PZT powder was uniformly dispersed in the CNF films and showed the morphotropic phase boundary (MPB) in PZT/CNF films. The addition of CNF in PZT has improved the mechanical strength significantly.

For environment-friendly renewable energy, blue energy, which is ocean-related energy, has gained an increasing interest due to its huge potential and vast wasted energy. This study suggests a promising buoy-type ocean energy harvesting structure based on a thermoplastic polymer, poly(methyl methacrylate) (PMMA) as a dielectric film for ocean monitoring system. The PMMA dielectric thin film can be easily fabricated with nanopatterned morphological characteristics by thermal nanoimprinting lithography. The buoy-type suggested energy harvesting structure can convert ocean wave energy into electrical energy to power a commercially available Li-ion battery using a regulator-based circuit.

Extrusion-based 3D printing is widely used to fabricate precise and accurate 3D structures with nanocellulose suspensions due to its excellent material flow control and system stability. The current issues related to high concentration nanocellulose 3D structures are low printability, layers adhesion, shape fidelity, and mechanical strength. Herein, the issues associated with 3D printed concentrated nanocellulose structures were resolved by mixing different concentrations of tannic acid. The printing parameters of a twin-screw extruder, tannin acid content, and drying conditions were optimized for concentrated nanocellulose paste. The mechanical results showed that tannic acid effectively improved the adhesion between printed layers, as confirmed by a scanning electron microscope.

In this study, the Surface Acoustic Wave (SAW) sensor was designed according to the length of the delay line, and its performance during the detection was studied as the design variable. Dimethyl methylphosphonate (DMMP), which imitates the chemical structure of nerve agent sarin and is relatively less toxic, was used to study the performance of gas detection in which POSS-TU (polyhedral oligomeric silsesquioxane – thiourea) was used as the sensing material. The experiments showed the frequency shift characteristics of the sensors. Among the sensors with the design error values, a specific sensor had the largest difference in the frequency shift between the first and second peaks. Also, both the noise and reactivity were better than other sensors. The fastest reversible characteristics in the recovery time were observed.

Ultra-wideband terahertz (THz) and infrared (IR) absorbers offer enormous technical and economic promise for applications such as THz/IR-imaging, medical diagnoses, communication, spectroscopy, explosive detection, and weather monitoring. However, their usefulness is limited since they suffer from fabrication difficulty due to multi layered complex structure, narrowband and weak absorption. It is highly challenging to develop absorbers having compact, wide bandwidth, high gain and good radiation efficiency. We have here proposed a planar absorber that gives the most promising solutions to the rapid development of the aforementioned technologies. In this article a new design concept of gradient planar absorber based on the combination of circular split rings and log-spiral structures has been proposed for ultra-wideband EM wave absorption. A large absorption bandwidth of 46 THz (4 THz to 50 THz) covering the terahertz (THz) and mid-infrared (MIR) frequency bands with a mean absorption h

In this study, the effect of anionic surfactant, sodium dodecyl sulfate (SDS), on the structure and thermal insulation properties of the citric acid crosslinked CNF foam is investigated. The addition of the SDS improves the foam structure, and the prepared CNF foam indicates a porosity of around 99% and a density of around 20 mg/cm3 with very low shrinkage. SEM and FTIR are used to examine the morphology and chemical interactions. Further, the effect of the SDS on the thermal conductivity of the foam is investigated, and the foam shows thermal conductivity comparable with polyurethane foam.