Development Of Soft Materials Research Articles

Three‐in‐One Portable Electronic Sensory System Based on Low‐Impedance Laser‐Induced Graphene On‐Skin Electrode Sensors for Electrophysiological Signal Monitoring

AbstractOn‐skin sensors can precisely perceive important electrophysiological signals, including electroencephalogram (EEG), electrocardiogram (ECG), and electromyogram (EMG). Despite significant advances in the development of soft materials as electrode sensors, data acquisition (DAQ) unit—another indispensable component of on‐skin electronic sensory systems—typically exhibits bulkiness or unimodal sensing, which is detrimental to the portability of the sensory system or the comprehensiveness of the perceived information. Here, a portable and multimodal DAQ unit to tackle these challenges is designed. By assembling the DAQ unit with low‐impedance (<100 Ω) laser‐induced graphene on‐skin electrode sensors, a wireless communication module, a power supply module, and a 3D printed protective shell, the completed sensory system can realize three‐in‐one monitoring of EEG, ECG, and EMG with a light weight of 22 g and a low cost of $25. Moreover, a mobile App is developed to display the perceived electrophysiological signals in real time. Human–machine interface and embedded machine learning are demonstrated using the designed sensory system, indicating its potential applications in artificial intelligence. The success of this inexpensive three‐in‐one portable electronic sensory system sheds light on design, fabrication, and commercialization of multifunctional wearable electronics with wide applications in fitness tracking, medical diagnostics, and human–machine interface.

The Machines from Our Future

Abstract While the last sixty years have defined the field of industrial robots and empowered hard-bodied robots to execute complex assembly tasks in constrained industrial settings, the next sixty years will usher in our time with pervasive robots that come in a diversity of forms and materials and help people with physical tasks. The past sixty years have mostly been inspired by the human form, but the form diversity of the animal kingdom has broader potential. With the development of soft materials, machines and materials are coming closer together: machines are becoming compliant and fluid-like materials, and materials are becoming more intelligent. This progression raises the question: what will be the machines from our future?

Progress on triboelectric nanogenerator with stretchability, self-healability and bio-compatibility

Remarkable progress has been made recently in the development of soft materials and devices for human-machine interface. Emerging soft-electronics with skin-inspired stretchable, healable and bio-degradable properties have diffused the boundaries of electronics and biology. Practical utilisation of these electronics relies on the development of a skin-inspired soft energy harvester to power them. Mechanical energy harvesters including triboelectric and piezoelectric nanogenerators have emerged as promising energy harvesters for soft-electronics. In this review, we highlight the recent progress in stretchable, self-healing, and bio-compatible soft triboelectric nanogenerators. We explicitly discussed the operating mechanism, design strategies, fabrication techniques, and performances of the stretchable and self-healing energy harvesters. Additionally, the progress of bio-compatible energy harvesters for effective interaction with biological systems is discussed. Finally, we present the perspectives, existing challenges and future road-map for the development of skin-inspired soft mechanical energy harvesters.

3D printed electrically-driven soft actuators

Soft robotics is an emerging field enabled by advances in the development of soft materials with properties commensurate to their biological counterparts, for the purpose of reproducing locomotion and other distinctive capabilities of active biological organisms. The development of soft actuators is fundamental to the advancement of soft robots and bio-inspired machines. Among the different material systems incorporated in the fabrication of soft devices, ionic hydrogel–elastomer hybrids have recently attracted vast attention due to their favorable characteristics, including their analogy with human skin. Here, we demonstrate that this hybrid material system can be 3D printed as a soft dielectric elastomer actuator (DEA) with a unimorph configuration that is capable of generating high bending motion in response to an applied electrical stimulus. We characterized the device actuation performance via applied (i) ramp-up electrical input, (ii) cyclic electrical loading, and (iii) payload masses. A maximum vertical tip displacement of 9.78 ± 2.52 mm at 5.44 kV was achieved from the tested 3D printed DEAs. Furthermore, the nonlinear actuation behavior of the unimorph DEA was successfully modeled using an analytical energetic formulation and a finite element method (FEM).

Bio-inspired metal-coordinate hydrogels with programmable viscoelastic material functions controlled by longwave UV light.

Control over the viscoelastic mechanical properties of hydrogels intended for use as biomedical materials has long been a goal of soft matter scientists. Recent research has shown that materials made from polymers with reversibly associating transient crosslinks are a promising strategy for controlling viscoelasticity in hydrogels, for example leading to systems with precisely tunable mechanical energy-dissipation. We and others have shown that bio-inspired histidine:transition metal ion complexes allow highly precise and tunable control over the viscoelastic properties of transient network hydrogels. In this paper, we extend the design of these hydrogels such that their viscoelastic properties respond to longwave UV radiation. We show that careful selection of the histidine:transition metal ion crosslink mixtures allows unique control over pre- and post-UV viscoelastic properties. We anticipate that our strategy for controlling stimuli-responsive viscoelastic properties will aid biomedical materials scientists in the development of soft materials with specific stress-relaxing or energy-dissipating properties.

Advances in Soft Functional Materials Research

Advances in Soft Functional Materials Research

Three-dimensional digital image correlation measurement of mechanical properties of soft materials

The rapid development of soft materials in recent years gives revolutionary impact on electronics and biomedical industries. To better control the quality and key technology, mechanical properties of soft materials employed in electronics and biomedical industries must be accurately determined. By employing the non-destructive, non-contact and whole-field characteristics of the three-dimensional (3D) digital image correlation (DIC) method, mechanical properties of three kinds soft materials, i.e. epoxy resin used in photoviscoelasticity, optical films used in backlight modules of the thin film transistor liquid display (TFT-LCD) and artificial meshes used in biomedical applications were investigated in this paper. It was found that satisfactory accuracy and measurement range can be obtained from the 3D-DIC method on the measurement of mechanical properties of soft materials.

Applications and Development of Soft Materials in DC/DC Converter Modules

DC/DC converter modules have been used in military and civil industrials on a large scale. This paper mainly elaborates the application scope and characteristics of soft materials, which are used in DC/DC converter modules, and the effect of core type and integrating method on converter modules were researched. The development trend is pointed out combining with the technology of DC/DC converter modules.

イオン液体とソフトマテリアル

イオン液体とソフトマテリアル