scholarly journals Effect of Viscosity on the Formation of Porous Polydimethylsiloxane for Wearable Device Applications

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1471
Author(s):  
Dong-Hyun Baek ◽  
Hachul Jung ◽  
Jeong Hun Kim ◽  
Young Wook Park ◽  
Dae Wook Kim ◽  
...  
Keyword(s):  
Porous Structure ◽  
Three Dimensional ◽  
Cost Effective ◽  
Soft Materials ◽  
Wearable Devices ◽  
Porous Structures ◽  
Relative Resistance ◽  
Patch Type ◽  
Device Applications ◽  
Initial Resistance

Medical devices, which enhance the quality of life, have experienced a gradual increase in demand. Various research groups have attempted to incorporate soft materials such as skin into wearable devices. We developed a stretchable substrate with high elasticity by forming a porous structure on polydimethylsiloxane (PDMS). To optimize the porous structure, we propose a manufacturing process that utilizes a high-pressure steam with different viscosities (400, 800, 2100, and 3000 cP) of an uncured PDMS solution. The proposed method simplifies the manufacturing of porous structures and is cost-effective compared to other technologies. Porous structures of various viscosities were formed, and their electrical and mechanical properties evaluated. Porous PDMS (3000 cP) was formed in a sponge-like three-dimensional porous structure, compared to PDMS formed by other viscosities. The elongation of porous PDMS (3000 cP) was increased by up to 30%, and the relative resistance changed to less than 1000 times with the maximum strain test. The relative resistance increased the initial resistance (R0) by approximately 10 times during the 1500-times repeated cycling tests with 30% strain. As a result, patch-type wearable devices based on soft materials can provide an innovative platform that can connect with the human skin for robotics applications and for continuous health monitoring.

Fabrication of Functionally Porous Structures by the Sheet Lamination Method

2007 ◽  
Vol 561-565 ◽  
pp. 1711-1714 ◽  
Author(s):  
K. Yamasaki ◽  
S. Fukuda ◽  
Takashi Murakami ◽  
K. Maekawa
Keyword(s):  
Porous Structure ◽  
Cross Sections ◽  
Fractal Structure ◽  
Three Dimensional ◽  
Tissue Growth ◽  
Porous Structures ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Recent Trends ◽  
Materials Used

Recent trends in bio technology have resulted in the need for accurate fabrication of pore structure of sophisticated porous materials used in advanced applications such as substrates for tissue growth, and various kinds of implants. Control of pore size is important for promoting growth of blood vessels and adequate fluid flow. In the present study, an attempt has been made to fabricate functionally porous structures using titanium, including an internally controlled three-dimensional (3-D) fractal structure. A novel 3-D modeling method that combines rapid prototyping with spark plasma sintering (SPS) is proposed, which enables us to control the internal porous structure. Titanium powder-tape or sheet is sintered or cut by a pulsed Nd:YAG laser to form 2-D fractal cross-sections. These 2-D layers are temporarily laminated in a carbon mold, being then jointed by the SPS method to maintain the internal porous structure. Process parameters for the sheet lamination method have extensively been investigated.

scholarly journals Three-dimensional highly conductive silver nanowires sponges based on cotton-templated porous structures for stretchable conductors

RSC Advances ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Chun-Hua Zhu ◽  
Li-Ming Li ◽  
Jian-Hua Wang ◽  
Ye-Ping Wu ◽  
Yu Liu
Keyword(s):  
Mechanical Properties ◽  
Porous Structure ◽  
Silver Nanowires ◽  
Three Dimensional ◽  
Porous Structures ◽  
Binary Structure ◽  
Stretchable Conductors ◽  
Stretchable Conductor

A stretchable conductor was explored by embedding a binary structure fabricated from an interconnected porous structure of cotton as skeleton along with supported 2D AgNWs network into PDMS, which showed excellent electrical and mechanical properties.

scholarly journals High-Porosity Foam-Based Iontronic Pressure Sensor with Superhigh Sensitivity of 9280 kPa−1

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Qingxian Liu ◽  
Yuan Liu ◽  
Junli Shi ◽  
Zhiguang Liu ◽  
Quan Wang ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Mechanical Stability ◽  
Three Dimensional ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Cost Effective ◽  
Soft Materials ◽  
Polyurethane Foams ◽  
High Porosity ◽  
Functional Layer

Abstract Flexible pressure sensors with high sensitivity are desired in the fields of electronic skins, human–machine interfaces, and health monitoring. Employing ionic soft materials with microstructured architectures in the functional layer is an effective way that can enhance the amplitude of capacitance signal due to generated electron double layer and thus improve the sensitivity of capacitive-type pressure sensors. However, the requirement of specific apparatus and the complex fabrication process to build such microstructures lead to high cost and low productivity. Here, we report a simple strategy that uses open-cell polyurethane foams with high porosity as a continuous three-dimensional network skeleton to load with ionic liquid in a one-step soak process, serving as the ionic layer in iontronic pressure sensors. The high porosity (95.4%) of PU-IL composite foam shows a pretty low Young’s modulus of 3.4 kPa and good compressibility. A superhigh maximum sensitivity of 9,280 kPa−1 in the pressure regime and a high pressure resolution of 0.125% are observed in this foam-based pressure sensor. The device also exhibits remarkable mechanical stability over 5,000 compression-release or bending-release cycles. Such high porosity of composite structure provides a simple, cost-effective and scalable way to fabricate super sensitive pressure sensor, which has prominent capability in applications of water wave detection, underwater vibration sensing, and mechanical fault monitoring.

scholarly journals Reprogrammable shape morphing of magnetic soft machines

2020 ◽  
Vol 6 (38) ◽  
pp. eabc6414 ◽  
Author(s):  
Yunus Alapan ◽  
Alp C. Karacakol ◽  
Seyda N. Guzelhan ◽  
Irem Isik ◽  
Metin Sitti
Keyword(s):  
High Throughput ◽  
Design Space ◽  
High Spatial Resolution ◽  
Three Dimensional ◽  
Soft Materials ◽  
Wearable Devices ◽  
Soft Robot ◽  
Magnetic Domains ◽  
Metamaterial Structure ◽  
Shape Morphing

Shape-morphing magnetic soft machines are highly desirable for diverse applications in minimally invasive medicine, wearable devices, and soft robotics. Despite recent progress, current magnetic programming approaches are inherently coupled to sequential fabrication processes, preventing reprogrammability and high-throughput programming. Here, we report a high-throughput magnetic programming strategy based on heating magnetic soft materials above the Curie temperature of the embedded ferromagnetic particles and reorienting their magnetic domains by applying magnetic fields during cooling. We demonstrate discrete, three-dimensional, and reprogrammable magnetization with high spatial resolution (~38 μm). Using the reprogrammable magnetization capability, reconfigurable mechanical behavior of an auxetic metamaterial structure, tunable locomotion of a surface-walking soft robot, and adaptive grasping of a soft gripper are shown. Our approach further enables high-throughput magnetic programming (up to 10 samples/min) via contact transfer. Heat-assisted magnetic programming strategy described here establishes a rich design space and mass-manufacturing capability for development of multiscale and reprogrammable soft machines.

Discotic columnar liquid-crystalline polymer semiconducting materials with high charge-carrier mobility via rational macromolecular engineering

2017 ◽  
Vol 8 (21) ◽  
pp. 3286-3293 ◽  
Author(s):  
Bin Mu ◽  
Xingtian Hao ◽  
Jian Chen ◽  
Qian Li ◽  
Chunxiu Zhang ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Cost Effective ◽  
Crystalline Polymer ◽  
Charge Carrier Mobility ◽  
Optoelectronic Device ◽  
Side Chain ◽  
Liquid Crystal Polymers ◽  
Semiconducting Materials ◽  
Organic Semiconducting Materials ◽  
Device Applications

Well-prepared side-chain discotic liquid crystal polymers with shorter spacers in ordered columnar phases are fascinating and promising cost-effective, solution-processable organic semiconducting materials for various potential optoelectronic device applications.

scholarly journals Design of Thermal Insulation Materials with Different Geometries of Channels

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2217
Author(s):  
Daniela Șova ◽  
Mariana Domnica Stanciu ◽  
Sergiu Valeriu Georgescu
Keyword(s):  
Thermal Conductivity ◽  
Porous Structure ◽  
Base Material ◽  
Cost Effective ◽  
Heat Radiation ◽  
Average Temperature ◽  
Temperature Regimes ◽  
The Face ◽  
Inclined Channels ◽  
Air Channels

Investigating the large number of various materials now available, some materials scientists promoted a method of combining existing materials with geometric features. By studying natural materials, the performance of simple constituent materials is improved by manipulating their internal geometry; as such, any base material can be used by performing millimeter-scale air channels. The porous structure obtained utilizes the low thermal conductivity of the gas in the pores. At the same time, heat radiation and gas convection is hindered by the solid structure. The solution that was proposed in this research for obtaining a material with porous structure consisted in perforating extruded polystyrene (XPS) panels, as base material. Perforation was performed horizontally and at an angle of 45 degrees related to the face panel. The method is simple and cost-effective. Perforated and simple XPS panels were subjected to three different temperature regimes in order to measure the thermal conductivity. There was an increase in thermal conductivity with the increase in average temperature in all studied cases. The presence of air channels reduced the thermal conductivity of the perforated panels. The reduction was more significant at the panels with inclined channels. The differences between the thermal conductivity of simple XPS and perforated XPS panels are small, but the latter can be improved by increasing the number of channels and the air channels’ diameter. Additionally, the higher the thermal conductivity of the base material, the more significant is the presence of the channels, reducing the effective thermal conductivity. A base material with low emissivity may also reduce the thermal conductivity.

scholarly journals Cyber-Physical Systems Improving Building Energy Management: Digital Twin and Artificial Intelligence

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2338
Author(s):  
Sofia Agostinelli ◽  
Fabrizio Cumo ◽  
Giambattista Guidi ◽  
Claudio Tomazzoli
Keyword(s):  
Artificial Intelligence ◽  
Renewable Energy ◽  
Energy Management ◽  
Three Dimensional ◽  
Cost Effective ◽  
Automation System ◽  
Climate Conditions ◽  
Digital Twin ◽  
Building Energy Management ◽  
Computing Paradigm

The research explores the potential of digital-twin-based methods and approaches aimed at achieving an intelligent optimization and automation system for energy management of a residential district through the use of three-dimensional data model integrated with Internet of Things, artificial intelligence and machine learning. The case study is focused on Rinascimento III in Rome, an area consisting of 16 eight-floor buildings with 216 apartment units powered by 70% of self-renewable energy. The combined use of integrated dynamic analysis algorithms has allowed the evaluation of different scenarios of energy efficiency intervention aimed at achieving a virtuous energy management of the complex, keeping the actual internal comfort and climate conditions. Meanwhile, the objective is also to plan and deploy a cost-effective IT (information technology) infrastructure able to provide reliable data using edge-computing paradigm. Therefore, the developed methodology led to the evaluation of the effectiveness and efficiency of integrative systems for renewable energy production from solar energy necessary to raise the threshold of self-produced energy, meeting the nZEB (near zero energy buildings) requirements.

scholarly journals Dimensional transformation of chemical bonding during crystallization in a layered chalcogenide material

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuta Saito ◽  
Shogo Hatayama ◽  
Yi Shuang ◽  
Paul Fons ◽  
Alexander V. Kolobov ◽  
...  
Keyword(s):  
Chemical Bonding ◽  
Crystalline Phase ◽  
Three Dimensional ◽  
Atomic Layer ◽  
Unusual Behavior ◽  
Weakly Bound ◽  
Covalently Bonded ◽  
Non Volatile Memory ◽  
Device Applications ◽  
Memory Applications

AbstractTwo-dimensional (2D) van der Waals (vdW) materials possess a crystal structure in which a covalently-bonded few atomic-layer motif forms a single unit with individual motifs being weakly bound to each other by vdW forces. Cr2Ge2Te6 is known as a 2D vdW ferromagnetic insulator as well as a potential phase change material for non-volatile memory applications. Here, we provide evidence for a dimensional transformation in the chemical bonding from a randomly bonded three-dimensional (3D) disordered amorphous phase to a 2D bonded vdW crystalline phase. A counterintuitive metastable “quasi-layered” state during crystallization that exhibits both “long-range order and short-range disorder” with respect to atomic alignment clearly distinguishes the system from conventional materials. This unusual behavior is thought to originate from the 2D nature of the crystalline phase. These observations provide insight into the crystallization mechanism of layered materials in general, and consequently, will be useful for the realization of 2D vdW material-based functional nanoelectronic device applications.

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