The main goal of this work is to develop a fabrication process and system for silver/silver chloride (Ag/AgCl)-coated yarn, as Ag/AgCl is the preferred non-polarizing material for interfacing with the body in a clinical setting when monitoring biological signals. A roll-to-roll electrochemical system was designed and built to deposit AgCl on Ag-coated nylon 6,6 yarn in a controllable process. In particular, the movement of the yarn, voltage limit and mixing of 0.9% sodium chloride solution were held constant while the applied current was varied. The Ag-coated nylon acted as the working electrode with two counter electrodes made of platinum. The optimal Ag/AgCl yarns were then further characterized. The roll-to-roll parameters identified include the applied current of approximately 1.82 mA/cm 2 for the Ag-coated nylon yarn with a voltage limit of 2.00 V while in the electrochemical chamber. In addition, the yarn had a uniform movement of 0.08 cm/s, which meant that 7 cm of yarn was in the chamber for approximately 89.17 s. The fabrication process was relatively repeatable, yielding the average resistance of 11.0 ± 1.8 Ω/cm for the optimal Ag/AgCl-coated yarn with a low standard deviation between different fabrication processes. A proof-of-concept system was developed and parameters important for the fabrication of functional Ag/AgCl electronic textiles (e-textiles) were detailed. An effective roll-to-roll fabrication method for Ag/AgCl-coated yarns has the potential to significantly contribute to the design and development of wearable e-textile biological monitoring systems that require Ag/AgCl sensor materials.

Silver chloride

10.1177/0040517518817060

Cite

Citations (3)

Future opportunities and challenges of electrospinning

Cambridge University Press eBooks (2014)

Frank Ko Yuqin Wan

In 2000, Roco et al. [1] estimated that there would be two million nanotechnology workers worldwide (800 000 in the United States) and the product value would reach $1 trillion, of which $800 billion would be in the United States, by 2015, with a 25% rate growth. The initial estimation for the quasi-exponential growth in the nanotechnology workforce and the product value held up to 2008, as shown in Fig.10.1. The market is doubling every three years as a result of the successive introduction of new products, and new generations of nanotechnology products are expected to enter the market within the next few years [1]. So the estimated value of 2015 for both workforce and product value would have been realized as the 25% growth rate is expected to continue.

Value (mathematics)

10.1017/cbo9781139021333.011

Cite

Citations (0)

Experimental study on compression properties and failure mechanism of 3D MWK carbon/epoxy composites at elevated temperatures

Polymer Composites (2017)

Nan Jiang Dian‐sen Li Qianqian Yao Hong-Wei Duan Frank Ko

The compressive behavior of the 3D MWK carbon/epoxy composites with two fiber architectures were performed in longitudinal and transverse directions at room and elevated temperatures. Macro-fracture and SEM micrographs were examined to understand the deformation and failure mechanism of 3D MWK carbon/epoxy composites. The results show that the compression properties and failure patterns vary with the temperature, fiber architecture, and loading mode. The compressive stress–strain curves and properties are different in longitudinal and transverse directions. Meanwhile, the properties increase with the increase of fiber orientation angle and decrease significantly with the increase of temperature, especially after 75°C. Moreover, for longitudinal compression, material A [0°/90°/+45°/-45°] exhibits shear brittle feature and that the delaminating failure at elevated temperatures, while material B[0°/0°/0°/0°] behaves multiple shear fracture at 45°. For transverse compression, material A shows delaminating fracture along 0°, 90°, +45°, −45° fiber layers and material B is the delaminating between 0° fiber layers. At elevated temperatures, the damage of matrix yielding, cracking, and interface debonding become prominent, the composite becomes more softened and attains plasticity. POLYM. COMPOS., 39:E1987–E1999, 2018. © 2018 Society of Plastics Engineers

Brittleness

10.1002/pc.24372

Cite

Citations (8)

Hybrid PTFE-glass hierarchical braided/epoxy composites with self-lubricating and high tribological performance

Journal of Industrial Textiles (2020)

Saeed Reza Zahabi Mohammad Sheikhzadeh Saleh Akbarzadeh Ramazan Ali Abuzade Frank Ko

In this study hybrid polytetrafluoroethylene (PTFE)/glass fibers were employed in hierarchical braided structure as a composite reinforcement. PTFE-covered glass fibers were braided to achieve the hierarchical structure, then the composites were prepared through vacuum assisted resin transfer molding (VARTM) process. Tribological experiments were performed on the composites. The results showed self-lubricating and lower dynamic friction coefficient due to the PTFE transfer film formation. SEM micrographs confirmed the transfer film formation. Friction coefficient of 0.112, 0.105 and 0.096 were obtained under loading of 20, 30 and 40 N forces, respectively. The experimental coefficient of friction results were confirmed by mixture theory. The self-lubricating feature of PTFE-glass braided epoxy composite along with its mechanical characteristics makes it a feasible alternative for traditional wet bearing parts.

Polytetrafluoroethylene

Transfer molding

Molding (decorative)

10.1177/1528083720977210

Cite

Citations (12)

Functional Nanofibre: Enabling Material for the Next Generation Smart Textiles

Journal of Fiber Bioengineering and Informatics (2008)

Frank Ko Heejae Yang

Functional fibrous materials are a new family of fibre materials whose physical and chemical properties are sensitive to the change in the environment such as temperature, pressure, electric field, magnetic field, optical wavelength, adsorbed gas molecules and the pH value. This paper introduces a new approach to translate functions from nanoparticles to fibrous structures by co-electrospinning. Examples of nanofibres that have tailorable mechanical, electrical, magnetic, optical, thermal, hygroscopic, and antimicrobial functions are shown. The paper concludes with an example of the development of a multifunctional nanofibre scaffold for cartilage tissue regeneration.

Smart material

10.3993/jfbi09200801

Cite

Citations (35)