Effect of the Geometrical Structure on the Superhydrophobicity and Self-Cleaning Properties of Plasma-Treated Polyvinylidene Fluoride Fabrics.

The purpose of this study is to develop superhydrophobic polyvinylidene fluoride (PVDF) fabrics to increase their water repellency and self-cleaning properties and to investigate the effects of the inherent fabric roughness on these properties. A PVDF fabric, composed entirely of electrospun PVDF filament yarns, and two PVDF/polyester (PET) fabrics with different weave densities are used. After treatment with O plasma for 12 min and CF plasma for 4 min, superhydrophobicity is achieved in all fabrics, resulting in an increase in water repellency and self-cleaning efficiency.

Surface Wettability Prediction Using Image Analysis and an Artificial Neural Network.

In this study, a wettability-predicting method that uses an artificial neural network (ANN) by learning from digital images of the actual surface structures was developed. Polyester film surfaces were treated with oxygen plasma to realize various nanostructured surfaces. Surface structural characteristics from SEM images were quantified in a multifaceted way using a box-counting algorithm, a gray-level co-occurrence matrix algorithm, and binary image analysis.

The Effect of Fiber Type and Yarn Diameter on Superhydrophobicity, Self-Cleaning Property, and Water Spray Resistance.

In this study, we proved that micro/micro hierarchical structures are enough to achieve a superhydrophobic surface using polydimethylsiloxane (PDMS) dip-coating. Furthermore, the effect of fiber type and yarn diameter on superhydrophobicity and water spray resistance was investigated. Polyester fabrics with two types of fibers (staple fabric and filament) and three types of yarn diameters (177D, 314D, and 475D) were used.

Development of Energy-Efficient Superhydrophobic Polypropylene Fabric by Oxygen Plasma Etching and Thermal Aging.

This study developed a human-friendly energy-efficient superhydrophobic polypropylene (PP) fabric by oxygen plasma etching and short-term thermal aging without additional chemicals. The effect of the microroughness on the superhydrophobicity was examined by adjusting the weave density. After the PP fabric was treated with oxygen plasma etching for 15 min and thermal aging at 120 °C for 1 h (E15H120 1 h), the static contact and shedding angles were 162.

Objective quantification of surface roughness parameters affecting superhydrophobicity.

This study proposes new optical roughness parameters that can be objectively quantified using image processing techniques, and presents an analysis of how these parameters are correlated with the degree of superhydrophobicity. To this end, photolithography and dry etching processes were used to form regular square pillars with different heights and spacings with a length of tens of micro-meters on silicon wafers. Optical roughness parameters of the specimens were obtained using image processing, and surface wettability was characterized using static contact angle and sliding angle measurements for water droplets of volume = 3.

Effect of crystallinity on the recovery rate of superhydrophobicity in plasma-nanostructured polymers.

This study explored the optimum conditions to achieve superhydrophobicity in polyethylene terephthalate (PET) in terms of crystallinity and microstructure. Surface superhydrophobicity was achieved by nanostructures induced by oxygen plasma etching and the recovery process of low surface energy through thermal aging of various PETs; semi-crystalline biaxial PET (B-PET) film, amorphous PET (A-PET) film, and semi-crystalline PET (F-PET) fabric. Under the anisotropic plasma etching, the nanostructures on the B-PET film were the longest, followed by the F-PET fabric, which developed a hierarchical micro/nanostructure, then the A-PET film.

Integration of Polypyrrole Electrode into Piezoelectric PVDF Energy Harvester with Improved Adhesion and Over-Oxidation Resistance.

Smart textiles for wearable devices require flexibility and a lightweight, so in this study, a soft polypyrrole (PPy) electrode system was integrated into a piezoelectric polyvinylidenefluoride (PVDF) energy harvester. The PVDF energy harvester integrated with a PPy electrode had the piezoelectric output voltage of 4.24-4.

Facile fabrication of multifunctional fabrics: use of copper and silver nanoparticles for antibacterial, superhydrophobic, conductive fabrics.

This study aims to develop a multifunctional fabric for antibacterial, superhydrophobic and conductive performance using a facile fabrication method. Conductive metal particles, copper and silver, were used as antibacterial agents as well as a means to create nanoscale roughness on the fabric surface. Subsequent hydrophobic coating with 1-dodecanethiol produced a superhydrophobic surface.

Electric heated cotton fabrics with durable conductivity and self-cleaning properties.

This study was carried out to improve durability and reduce conductivity degradation of polypyrrole-deposited cotton fabrics by introducting a superhydrophobic surface. An polymerization method was used to polymerize the polypyrrole on the cotton fabric, and the surface energy was lowered using -dodecyltrimethoxysilane to create a superhydrophobic surface. In particular, to investigate the durability of the conductivity according to the superhydrophobic surface, the changes of surface resistance were examined after repeated exposure to air, moisture, and friction.

Development of a superhydrophobic electrospun poly(vinylidene fluoride) web plasma etching and water immersion for energy harvesting applications.

Smart textiles have been enormously developed recently, but attachment of batteries and low washing resistance are the major challenges in the development of wearable smart textiles. However, piezoelectric materials harvesting energy from mechanical action can be readily integrated with smart textiles and can replace conventional batteries. Therefore, energy harvesters with poly(vinylidene fluoride) (PVDF) were fabricated by the electrospinning process.

[Prevalence Of Intestinal Parasites In Korea].

A survey of intestinal parasites infection among Korean people has been carried out during July 1969 to December 1970. A total of 2,250 stool specimens (male 1,101, female 1,146) was collected from all the provinces and Seoul city in Korea. The specimens were examined routinely by direct fecal smear, zinc sulfate flotation and formalin-ether sedimentation techniques.