Development Of Sensors Research Articles

A flexible pressure sensor with wide detection range and high sensitivity based on glycerol@phosphoric acid nanofibers for human posture recognition applications

Flexible pressure sensors are widely used in wearable devices, especially in the field of human–computer interaction. Hence, the development of flexible pressure sensors with excellent sensitivity and detection range is essential. This paper introduces a flexible capacitive pressure sensor based on glycerol@phosphoric acid nanofibers, showcasing remarkable properties, including high sensitivity (53.97 kPa−1 at 300–1200 kPa), exceptionally wide detection range (1800 kPa), faster response/recovery time than human skin (14.4/9.6 ms), extremely low detection limit (5 Pa), outstanding stability (>10,000 fatigue tests), and excellent biocompatibility. In addition, the sensor was seamlessly integrated with deep learning algorithms, embedded systems, and internet technologies to develop a comprehensive human posture recognition system, which can adeptly capture and identify intricate human movements with an accuracy rate over 98 %. This system establishes a diagnostic channel between home patients and rehabilitation experts. Owing to its excellent sensitivity and detection range, the developed sensor presents promising prospects for future advancements in human–computer interaction.

Development of carbon dioxide sensor using fiber optic-based refractometer

In this work, a fiber optic-based refractometer has continuously been developed for measuring carbon dioxide (CO2) using the evanescent wave method. Consequently, this technique is utilized to determine the light absorption values. Further, the chemical compound is also used to coat onto the modified sensing probe. However, this probe is, generally, made from multi-mode fiber (MMF). Moreover, the principle of altering the refractive index (RI) value is applied by removing the cladding of the sensing probe using hydrofluoric acid (HF). In addition, the zinc oxide (ZnO) mixed with the sodium silicate (Na2SiO3), known for its CO2 absorption capabilities, is used as a compound to coat the modified cladding. Besides, the sensing probe has been developed in three selected lengths (L) which are 10, 20, and 25 mm, and then tested from 0 to 40 % of CO2 concentration. Moreover, a biogas analyzer has been operated as a standard reference instrument. Afterward, an engineering application software is also developed for data processing to analyze the data in the relationship between the differential voltage, percentage of attenuation, and percentage of concentration versus time domain, respectively. The experimental results reported that the developed sensing can detect CO2 in any sensing length from 8.11 to 38.25 % with a sensitivity of 0.0102 mV/%concentration. In addition, a percentage attenuation of 2.11 %, 14.52 %, and 29.29 % is achieved in whole sensing lengths. However, this analyzes that at 10 mm the probe is more suitable due to its high responsibility to detect the CO2. Furthermore, the experimental results showed that the selected compound can recover with a recovery time of approximately 6 min.

Construction of a Liquid Crystal Biosensor and Detection of Heavy Metal Ions and Organic Phosphate

Since the discovery of liquid crystal molecules have been widely used in electronic display devices. At the same time, as special “sensitive elements”, liquid crystal molecules have also been introduced into the field of sensors in recent years, especially in life science research, where they have been used to for constructing liquid crystal biosensors, the first appearance. Liquid crystal biosensors are fast, simple and low-cost, label-free, highly sensitive, and with low detection limits. Therefore, the development of new liquid crystal sensors is undoubtedly a great development in the field of chemical biosensors.

Review of Vision-Based Environmental Perception for Lower-Limb Exoskeleton Robots.

The exoskeleton robot is a wearable electromechanical device inspired by animal exoskeletons. It combines technologies such as sensing, control, information, and mobile computing, enhancing human physical abilities and assisting in rehabilitation training. In recent years, with the development of visual sensors and deep learning, the environmental perception of exoskeletons has drawn widespread attention in the industry. Environmental perception can provide exoskeletons with a certain level of autonomous perception and decision-making ability, enhance their stability and safety in complex environments, and improve the human-machine-environment interaction loop. This paper provides a review of environmental perception and its related technologies of lower-limb exoskeleton robots. First, we briefly introduce the visual sensors and control system. Second, we analyze and summarize the key technologies of environmental perception, including related datasets, detection of critical terrains, and environment-oriented adaptive gait planning. Finally, we analyze the current factors limiting the development of exoskeleton environmental perception and propose future directions.

Ultrasensitive and On‐Site Detection of Nitroaromatic Explosives Through a Dual‐Mode Hydrogel Sensor Utilizing Portable Devices

AbstractThe development of straightforward and dependable explosive sensors for on‐site identification is essential to preserving public safety concerns and lowering the safety risks related to explosions. However, one of the main barriers to the advancement of on‐site explosives detection in the future is the complexity of detection process. Here, a flexible hydrogel‐based sensing platform based on 3,4‐bis (4‐(1,2,2‐triphenylvinyl) phenyl) thiophene (TPE‐Z) and a methyl red design concept is shown that simultaneously achieves all targeted properties, including being quick, portable, reliable, and resistant to external interference. This composite fluorescent probe demonstrates outstanding detection capabilities, including low detection limits (0.48 mg L−1) and rapid response times (<5 s), which can be combined with smartphones for on‐site 2,4,6‐trinitrophenol (picric acid, PA) detection. Two independent fluorescence and colorimetric channels on the sensor showed selective response to PA under fluorescence and visible light irradiation, respectively. Meanwhile, the hydrogel sensor's distinct “turn on” and “turn off” response modes to PA can be utilized to construct “YES” and “NO” logic gates, which subsequently proves that they can be employed to differentiate PA on‐site. This sensing platform based on hydrogel is envisaged to offer in‐depth insights in advancing the on‐site detection of nitroaromatic explosives.

Recent progress of optical tactile sensors: A review

Over the past decade, flexible electronics has become a cutting-edge technology owing to its broad applications in robotics, health monitoring, and human-machine interface. The recent development of flexible electrical tactile sensor triggers the research of optical tactile sensors due to their potentials in high-sensitivity, high-precision, low power consumption, and anti-electromagnetic interference. Here, this review mainly discusses the advances and applications of silica fiber, polymer fiber, hydrogel, and micro/nanofiber based tactile sensors, specifically, focusing on the latest research results and on the necessary technologies to enable the health monitoring, robotics, and human-machine interface applications. Furthermore, future outlooks in developing skin-like optical tactile sensors are also presented.

Advanced Multiparallel-Connected Piezoresistive Physical Sensors: Elevating Performance Reliability of Flexible Strain and Pressure Sensors.

A physical sensor with a sensing medium comprising multiparallel-connected (MPC) piezoresistive pathways in both the vertical and horizontal directions was developed to achieve improved sensing performance. The MPC sensing medium reduces the total resistance and offsets noise, offering enhanced signal stability and device reliability and providing a high-performance sensing platform. The signal change and gauge factor (GF) of the 3PW-5L strain sensor (comprising three lines and five layers of piezoresistive pathways horizontally and vertically, respectively) were, respectively, 5.9 and 4.7 times higher than those of the 1PW-1L sensor composed of a monosensing pathway; the hysteresis of the detected signal was also significantly reduced. The linearity of the detected signal increased from 0.912 for 1PW-1L to 0.995 for 3PW-5L, indicating a greater sensing reliability. The direction of the applied tensile strain was successfully detected using the MPC sensing medium with an orthogonal configuration. The MPC piezoresistive sensor composing vertically stacked piezoresistive pathways demonstrated excellent performance as a pressure sensor; the 3PW-5L pressure sensor afforded a GF of 0.121 ± 0.002 kPa-1 with a linearity of 0.998 under an applied pressure ≥16.4 kPa. The MPC piezoresistive physical sensor offers a superior sensing performance and should contribute to the future development of wearable sensors and electronic devices.

Dual-parameter combined measurement sensor based on tri-metal structure

Simultaneous measurement of strain and temperature in vibrating environments has always been a key technical issue in the field of structural health monitoring. To address the bottleneck of inadequate dual-parameter measurement performance in existing Fiber Bragg Grating (FBG) strain and temperature sensors, a new type of fiber optic grating sensor with anti-vibration capabilities for the measurement of both strain and temperature is proposed. The sensor utilizes a flexible hinge structure made of 304 steel with high elastic modulus for strain sensitization and a bimetallic structure composed of 7075 aluminum and 4 J36 Invar alloy for temperature sensitization, integrating both types of sensors. Theoretical analysis of the sensor was conducted, followed by the fabrication of a prototype and the establishment of a testing system for performance evaluation. The results show that the designed dual-parameter FBG sensor has a strain sensitivity of approximately 3.06 pm/µε, about 2.62 times that of a bare FBG, and a temperature sensitivity of about 50.2 pm/℃, roughly 4.97 times that of a bare FBG. In anti-vibration performance tests between 5–100 Hz, the wavelength drift of the strain and temperature sections of the FBG in the sensor were both within 1 pm, meeting the requirements for simultaneous measurement of strain and temperature in vibrating environments. These findings provide a reference for the development of similar sensors and further improvement of the measurement performance of FBG strain and temperature sensors.

Development of an Innovative Biosensor Based on Graphene/PEDOT/Tyrosinase for the Detection of Phenolic Compounds in River Waters.

Phenolic compounds, originating from industrial, agricultural, and urban sources, can leach into flowing waters, adversely affecting aquatic life, biodiversity, and compromising the quality of drinking water, posing potential health hazards to humans. Thus, monitoring and mitigating the presence of phenolic compounds in flowing waters are essential for preserving ecosystem integrity and safeguarding public health. This study explores the development and performance of an innovative sensor based on screen-printed electrode (SPE) modified with graphene (GPH), poly(3,4-ethylenedioxythiophene) (PEDOT), and tyrosinase (Ty), designed for water analysis, focusing on the manufacturing process and the obtained electroanalytical results. The proposed biosensor (SPE/GPH/PEDOT/Ty) was designed to achieve a high level of precision and sensitivity, as well as to allow efficient analytical recoveries. Special attention was given to the manufacturing process and optimization of the modifying elements' composition. This study highlights the potential of the biosensor as an efficient and reliable solution for water analysis. Modification with graphene, the synthesis and electropolymerization deposition of the PEDOT polymer, and tyrosinase immobilization contributed to obtaining a high-performance and robust biosensor, presenting promising perspectives in monitoring the quality of the aquatic environment. Regarding the electroanalytical experimental results, the detection limits (LODs) obtained with this biosensor are extremely low for all phenolic compounds (8.63 × 10-10 M for catechol, 7.72 × 10-10 M for 3-methoxycatechol, and 9.56 × 10-10 M for 4-methylcatechol), emphasizing its ability to accurately measure even subtle variations in the trace compound parameters. The enhanced sensitivity of the biosensor facilitates detection and quantification in river water samples. Analytical recovery is also an essential aspect, and the biosensor presents consistent and reproducible results. This feature significantly improves the reliability and usefulness of the biosensor in practical applications, making it suitable for monitoring industrial or river water.

Electrochemical detection of regorafenib using a graphite sheet electrode modified with nitrogen-doped reduced graphene oxide nanocomposite

Regorafenib (RGF) is a multi-kinase inhibitor drug used for treating various cancers, posing challenges for detection in biological samples due to low solubility and stability. This paper presents a novel electrochemical sensor based on a monolith reduced graphene oxide (M-RGO) nanocomposite modified graphite sheet electrode. M-RGO was synthesized via a hydrothermal method and characterized extensively. The electrochemical performance was assessed using cyclic voltammetry and differential pulse voltammetry. The sensor demonstrated exceptional electrocatalytic activity for RGF oxidation, featuring two linear response ranges (31 nM to 600 nM and 600 nM to 920 nM) with a detection limit of 1.7 nM. The sensor exhibited good selectivity, stability, and reproducibility. Successful application in determining RGF in human serum and urine samples demonstrated the potential of M-RGO nanocomposite as a promising material for the development of electrochemical sensors for pharmaceutical analysis.

Doped rare earth elements enhance gas sensing properties of hollow spiral-like Mn(OH)F semiconductor sensors for acetate esters detection

This study successfully synthesized a series of Mn(OH)F hollow structures doped with rare earth elements (Sm, Nd, Ce, and Tb) using a hydrothermal method. A comprehensive analysis was conducted on the influence of these dopant elements on the morphology and gas-sensitive properties of Mn(OH)F. The gas-sensing performance of Mn(OH)F nanomaterials doped with Sm, Nd, Ce, and Tb was extensively investigated at 150℃ for methyl acetate, ethyl acetate, propyl acetate, and butyl acetate. The results demonstrated good gas-sensing capabilities, with responses reaching 2.0, 2.0, 2.0, and 2.5, respectively. Compared to undoped Mn(OH)F nanomaterials, the operating temperature of these sensors was reduced by about 100℃, and the response values were nearly tripled. Exceptional selectivity and stability were also observed. In addition, an in-depth exploration was conducted into the underlying mechanisms behind the enhanced gas response due to rare earth element doping. This study provides strong theoretical support for the development of efficient acetate ester gas sensors, demonstrating broad prospects for their widespread application in the industrial field.

Novel virtual sensors development based on machine learning combined with convolutional neural-network image processing-translation for feedback control systems of internal combustion engines

Physical sensors are commonly used to record performance data of internal combustion engines (ICEs) for online feedback control and calibration, but they are prone to diagnostic and increased development costs. Lookup tables are commonly used in conventional calibration and feedback control; however, the table parameters increase with the advancement of ICE technologies under transient operations. Consequently, the calibration and control systems are time-consuming. This work proposes novel virtual sensors to address these issues by predicting the combustion, performance, and emission of ICEs using neural networks and image processing/translation. The novel sensors are targeted for onboard feedback control systems under transient driving. Firstly, a virtual diesel engine (VDE) was developed and calibrated against experimental data taken from a production 2.2 L turbocharged diesel engine. The VDE was calibrated under WLTC, JC08, and NEDC transient operations and was used to generate teaching data. Next, the virtual sensors are developed using five machine learning (ML) regressors. The result shows that the coefficient of determination R2 from all ML regressors exceeded 0.94, and the XG-Boost outperforms other ML techniques with R2 > 0.977. XG-Boost parameter estimations were 8 times faster than that on a desktop simulation. Then, an image classification model using a deep convolutional neural network (D-CNN) is constructed, and the dependency of performance parameters and exhaust emissions with the rate of heat release (R.H.R) and in-cylinder pressure profile is confirmed. The performance parameters and emissions dependency was compared individually with R.H.R. and the in-cylinder pressure profile. As a result, a strong correlation between the performance and R.H.R. was observed. Finally, a generative adversarial network (GAN) model was constructed to translate the in-cylinder pressure profile to R.H.R. profile. A novel method to develop virtual sensors for advanced feedback control of any type of ICEs is proposed for the first time.

Symmetrical Ligand's Fabricated Porous Silicon Surface Based Photoluminescence Sensor for Metal Detection and Entrapment.

This study was based on the development of surface-based photoluminescence sensor for metal detection, quantification, and sample purification employing the solid sensory chip having the capability of metal entrapment. The Co(II), Cu(II) and Hg(II) sensitive fluorescence sensor (TP) was first synthesized and characterized its sensing abilities towards tested metal ions by using fluorescence spectral investigation while the synthesis and complexation of the receptor was confirmed by the chromogenic, optical, spectroscopic and spectrometric analysis. Under optical investigation, the ligand solution exhibited substantial chromogenic changes as well as spectral variations upon reacting with copper, cobalt, and mercuric ions, while these behaviors were not seen for the rest of tested metallic ions i.e., Na+, Ag+, Ni2+, Mn2+, Pd2+, Pb2+, Cd2+, Zn2+, Sn2+, Fe2+, Fe3+, Cr3+, and Al3+. These colorimetric alterations and spectral shifting could potentially be employed to detect and quantify these specific metal ions. After the establishment of the ligand's selective complexation ability towards selected metals, it was fabricated over the substituted porous silicon surface (FPS) keeping in view of the development of surface-based photoluminescence sensor (TP-FPS) for the selected metal sensation and entrapment to purify the sample just be putting off the metal entrapped sensory solid chip. Surface characterization and ligand fabrication was inspected by plan and cross sectional electron microscopic investigations, vibrational and electronic spectral analysis. The sensitivity of the ligand (TP) in the solution phase metal discrimination was determined by employing the fluorescence titration analysis of the ligand solution after progressive induction of Co2+, Cu2+, and Hg2+, which afford the detection limit values of 2.14 × 10- 8, 3.47 × 10- 8 and 3.13 × 10- 3, respectively. Concurrently, photoluminescence titration of the surface fabricated sensor (TP-FPS) revealed detection limit values of 3.14 × 10- 9, 7.43 × 10- 9, and 8.21 × 10- 4, respectively, for the selected metal ions.

Development of toxic gas sensor from anthocyanin-embedded polycaprolactone-co-polylactic acid nanofibrous mat

The colorless ammonia gas has been a significant intermediate in the industrial sector. However, prolonged exposure to ammonia causes harmful effects to organs or even death. Herein, an environmentally friendly solid-state ammonia sensor was developed utilizing colorimetric polycaprolactone-co-polylactic acid nanofibrous membrane. Pomegranate (Punica granatum L.) peel contains anthocyanin (ACN) as a naturally occurring spectroscopic probe. A mordant (potassium aluminum sulfate) is used to immobilize the anthocyanin direct dyestuff inside nanofibers, generating mordant/anthocyanin (M/ACN) coordinated complex nanoparticles. When exposed to ammonia, the color change of anthocyanin-encapsulated polycaprolactone-co-polylactic acid nanofibrous membrane from purple to transparent was examined by absorbance spectra and CIE Lab color parameters. With a quick colorimetric shift, the polycaprolactone-co-polylactic acid fabric exhibits a detection limit of 5–150 mg/L. The absorbance spectra showed a hypsochromic shift when exposed to ammonia, displaying an absorption shift from 559 nm to 391 nm with an isosbestic point of 448 nm. Scanning electron microscopy (SEM) images revealed that the polycaprolactone-co-polylactic acid nanofibers had a diameter of 75–125 nm, whereas transmission electron microscopy (TEM) images revealed that M/ACN nanoparticles exhibited diameters of 10–20 nm.

Thiourea‐Modified Multiwalled Carbon Nanotubes as Electrochemical Biosensor for Ultra‐Precise Detection of Dopamine

Functionalized multi‐walled carbon nanotubes (MWCNTs) have enticed remarkable attention in the field of electrochemical sensing applications. Dopamine (DA) is a monoamine neurotransmitter released in the brain acting as a chemical messenger that communicates messages between nerve cells and the rest of the body. Therefore, there is a significant technological urge for the development of electrochemical sensors for DA in body fluids. In this context, nitrogen‐functionalized MWCNTs (TM‐CNT600) were fabricated by thermal annealing of carboxylic acid functionalized MWCNTs with thiourea at 600 oC under N2 atmosphere. The XPS spectrum reveals the presence of nitrogen‐containing functionalities in the as‐prepared TM‐CNT600. FTIR results show the presence of ‐OH, C‐N and C‐S functional groups. XPS further corroborates the FTIR results and quantifies the predominant functional groups in as‐prepared material. The material was investigated as a potential electrochemical sensor for the detection of dopamine (DA). In the case of TM‐CNT600/GCE, a linear relationship for DA concentration was observed in the range of 10.7 ‐ 24.2 μM with the limit of detection (LOD) of 1.42 μM using linear sweep voltammetry (LSV). These results highlight the potential of TM‐CNT600 modified GCE as an efficient sensor for the electrochemical detection of DA in body fluids.

An easy-to-prepare AIE fluorescent sensor based on bis-(naphthyl acetyl)-hydrazone for selectively relay detection of Fe3+, F− and H2PO4−

It is important to identify and detect ions as they are essential in the life system. The development of fluorescent sensors with easy-to-prepare and high sensitivity has always been a topic of widespread concern. Herein, an easily prepared fluorescent sensor based on bis-(naphthyl acetyl)-hydrazone (BNH) was successfully synthesized. Remarkably, the BNH exhibits blue aggregation-induced emission (AIE) fluorescence. The blue fluorescence of BNH was quenched by the addition of Fe3+, and then enhanced by the addition of F− and H2PO4−, while the fluorescence opened by F− was quenched again by Al3+. The LODs (limits of lowest detection) of BNH for Fe3+ is 4.46 × 10−7 M. This study provides a simple and feasible AIE fluorescence sensor synthesis method for efficient and sensitive detecting Fe3+, F− and H2PO4−.

Dual straight-wing FBG accelerometer for low-frequency vibration measurement

Fiber optic accelerometers have a wide range of applications in low-frequency vibration measurement, such as in earthquake monitoring, disaster early warning, underground resource exploration, and anti-seismic monitoring projects for critical structures like dams and bridges. In response to the current issues of Fiber Bragg Gratings (FBG) accelerometers being insensitive to low-frequency vibration signals and challenging to apply in engineering, a dual straight-wing FBG accelerometer for low-frequency vibration measurement is proposed. Firstly, a sensor model is established and theoretically analyzed. Secondly, the impact of the sensor's main structural parameters on sensitivity and natural frequency is analyzed, and the sensor is simulated using ANSYS. Finally, a prototype of the sensor is developed, and a low-frequency vibration testing system is set up to test the sensor's performance. Experimental results show that the accelerometer has a natural frequency of 39.1 Hz, operates in the 5–22 Hz frequency band, and has a sensitivity of 171.7 p.m./g, a dynamic range of 69.82 dB, and a transverse interference resistance of less than 9.5%. This research provides a new reference for the development of similar sensors.

Optimal Design and Development of Magnetic Field Detection Sensor for AC Power Cable.

The state detection of power cables is very important to ensure the reliability of the power supply. Traditional sensors are mostly based on electric field detection. The operation is complex, and its efficiency needs to be improved. This paper optimizes the design and development of the magnetic field detection sensor for AC power cables. First, through the establishment of the magnetic field sensor model, it is determined that permalloy is the material of the magnetic core, the optimal aspect ratio of the magnetic core is 20, and the ratio of coil length to core length is 0.3. Second, the coil-simulation model is established, and it is determined that the optimal number of turns of the coil is 11,000 turns, the diameter of the enameled copper wire is 0.08 mm, and the equivalent magnetic field noise of the sensor is 0.06 pT. Finally, the amplifying circuit based on negative magnetic flux feedback is designed, the sensor is assembled, and the experimental circuit is built for the sensitivity test. The results show that the sensitivity of the magnetic field sensor is 327.6 mV/μT. The sensor designed in this paper has the advantages of small size, high sensitivity, ease of carry, and high reliability.

Critical Assessment of Micellar Surface Charge-Dependent Disaggregation and Reaggregation of a Bis-Indole Self-Aggregate: What Should Be Our Case-Dependent Choice?

"Aggregation-caused quenching" is a deep-seated mechanism and has been widely used by the researchers as the possible basis for new sensor development. Contrast to aggregation, its turn around process, disaggregation, has gained much less consideration so far. Unfortunately, study of the further scope for reaggregation of the disaggregated probe assembly in the same solution, as and when required, is still under the rare category. The central theme of the current study is focused on this aspect. For this purpose, the effects of headgroup charge (cationic, anionic, and nonionic) and polarity of the micelles on the degree of disaggregation and subsequent emission amelioration of a synthesized bis-indole derivative, 3,3'-bisindolyl(phenyl)methane (BIPM), are studied using steady-state and time-resolved spectroscopic techniques. The relative emission yield of BIPM (φf = 0.01) is significantly enhanced in the presence of cetyltrimethylammonium bromide (φf = 0.21) and polyoxyethylene (20) sorbitan monolaurate (φf = 0.24), whereas comparatively less emission enhancement is recorded within the sodium dodecyl sulfate system (φf = 0.07). In contrast, addition of an external biophilic agent, uric acid, causes requenching of the enhanced emission because of the reaggregation of the disaggregated probes. Detailed microscopic and calorimetric studies are also adopted to investigate the disaggregation-reaggregation mechanism of BIPM associations. The study will provide prior insights about the use of suitable micellar systems for the required degree of disaggregation as well as for the modulation of emission efficiency by controlled tuning of the disaggregation-reaggregation equilibrium for similar probe associations in pure aqueous medium avoiding any chemical transformation.

PEGgel‐Based Multimodal Soft Sensors Capable of Decoupling Thermal and Mechanical Stimuli

AbstractInspired by human skin, soft sensors that are capable of sensing various external signals have been an active area of research. However, the vast majority of the developed soft sensors still lag far behind human skin in terms of multimodal sensing capability. Herein, this work reports on a multimodal soft sensor that can decouple thermal and mechanical signals. The sensor is made of poly(ethylene glycol) gel (PEGgel) containing ionic liquid, which is stretchable and transparent and shows decent strain and temperature sensing performances. Importantly, analysis of the ion relaxation dynamics shows that the charge relaxation time and capacitance change of the sensor are independently sensitive to the variations of temperature and mechanical deformation, respectively. By measuring the charge relaxation time and capacitance, the thermal and mechanical signals detected by the PEGgel sensor can be nicely decoupled without signal interference. Such a multimodal soft sensor may serve as a starting point for the development of lifelike soft sensors for high‐tech applications in a variety of fields such as soft robotics, the internet of things, and human–machine interaction.