Design of Lotus-Leaf-Like Decoration Materials

2012 ◽  
Vol 450-451 ◽  
pp. 881-884
Author(s):  
Rui Hong Wu
Keyword(s):  
Raw Materials ◽  
Organization Structure ◽  
Water Repellency ◽  
Structure Stability ◽  
Water Repellent ◽  
Interior Decoration ◽  
Lotus Leaf ◽  
Wrinkle Resistance ◽  
Fine Fiber ◽  
Nano Coating

Lotus leaf structures shows shelf-cleaning properties of water-repellent, it’s convenient to clean, especially the interior decoration materials. Polyester sea-island ultra-fine fiber was chosen as raw materials, the crepe weave was used as the organization structure, and finally through water-repellent nano-coating finishing to form a Lotus leaf-like surface, then the water repellency, the anti-fouling performance and the anti-ultraviolet performance of lotus-leaf-like materials was tested and analyzed. The conclusions drawn are as follows: the water repellency, the anti-fouling performance and the anti-ultraviolet performance of lotus-leaf-like decoration materials was excellent, the UV transmission of the materials was only 2%, which was far below the International standard and at the same time the results shows that the materials had good wrinkle resistance property, it can improve the structure stability.

Water-Repellent Stability of Superhydrophobic Materials under Hydrostatic Pressure

2014 ◽  
Vol 633-634 ◽  
pp. 764-768
Author(s):  
Jian Ye Huang ◽  
Feng Hui Wang
Keyword(s):  
Hydrostatic Pressure ◽  
Superhydrophobic Surface ◽  
Hierarchical Structures ◽  
Water Repellency ◽  
Total Reflection ◽  
Wetting Transition ◽  
Water Repellent ◽  
Lotus Leaf ◽  
Stability Of Water ◽  
Air Film

Keeping the water-repellent stability of superhydrophobic surface is necessary in application. Based on the total reflection of Cassie interface and vacuum technique, the superhydrophobic stability of the lotus leaf and an artificial material was investigated. The results show that during the Cassie-Wenzel transition, primary wetting transition occurs at a certain pressure that in accordance with theoretical prediction. However, when the air film is entrapped between microstructures, stability of water-repellency was greatly enhanced, and part of the wetting transition can be recovered when the pressure was released. Due to the micro-and nanoscale hierarchical structures, the lotus leaf shows better water-repellent stability and dewetting property than the artificial superhydrophobic surface when the hydrostatic pressure was applied and released.

Non-adhesive lotus and other hydrophobic materials

2008 ◽  
Vol 366 (1870) ◽  
pp. 1539-1556 ◽  
Author(s):  
David Quéré ◽  
Mathilde Reyssat
Keyword(s):  
Solid Surface ◽  
Room Temperature ◽  
Water Repellency ◽  
Short Review ◽  
Water Repellent ◽  
Practical Applications ◽  
Hydrophobic Materials ◽  
Volatile Liquid ◽  
Air Cushion ◽  
The Stability

Superhydrophobic materials recently attracted a lot of attention, owing to the potential practical applications of such surfaces—they literally repel water, which hardly sticks to them, bounces off after an impact and slips on them. In this short review, we describe how water repellency arises from the presence of hydrophobic microstructures at the solid surface. A drop deposited on such a substrate can float above the textures, mimicking at room temperature what happens on very hot plates; then, a vapour layer comes between the solid and the volatile liquid, as described long ago by Leidenfrost. We present several examples of superhydrophobic materials (either natural or synthetic), and stress more particularly the stability of the air cushion—the liquid could also penetrate the textures, inducing a very different wetting state, much more sticky, due to the possibility of pinning on the numerous defects. This description allows us to discuss (in quite a preliminary way) the optimal design to be given to a solid surface to make it robustly water repellent.

scholarly journals Superhydrophobicity in perfection: the outstanding properties of the lotus leaf

2011 ◽  
Vol 2 ◽  
pp. 152-161 ◽  
Author(s):  
Hans J Ensikat ◽  
Petra Ditsche-Kuru ◽  
Christoph Neinhuis ◽  
Wilhelm Barthlott
Keyword(s):  
Chemical Composition ◽  
Water Repellency ◽  
Contact Angles ◽  
Dense Layer ◽  
Lotus Effect ◽  
Nano Structure ◽  
Lotus Leaf ◽  
Water Drops ◽  
The Impact ◽  
Unique Chemical

Lotus leaves have become an icon for superhydrophobicity and self-cleaning surfaces, and have led to the concept of the ‘Lotus effect’. Although many other plants have superhydrophobic surfaces with almost similar contact angles, the lotus shows better stability and perfection of its water repellency. Here, we compare the relevant properties such as the micro- and nano-structure, the chemical composition of the waxes and the mechanical properties of lotus with its competitors. It soon becomes obvious that the upper epidermis of the lotus leaf has developed some unrivaled optimizations. The extraordinary shape and the density of the papillae are the basis for the extremely reduced contact area between surface and water drops. The exceptional dense layer of very small epicuticular wax tubules is a result of their unique chemical composition. The mechanical robustness of the papillae and the wax tubules reduce damage and are the basis for the perfection and durability of the water repellency. A reason for the optimization, particularly of the upper side of the lotus leaf, can be deduced from the fact that the stomata are located in the upper epidermis. Here, the impact of rain and contamination is higher than on the lower epidermis. The lotus plant has successfully developed an excellent protection for this delicate epistomatic surface of its leaves.

Performance Study of Nano-TiO2 Modified Fabric

2012 ◽  
Vol 549 ◽  
pp. 733-736
Author(s):  
Xiao Mian Chen ◽  
Jing Jing Shi ◽  
Hong Sha Su ◽  
Chun Ting Lin ◽  
En Long Yang
Keyword(s):  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Catalytic Properties ◽  
Antibacterial Property ◽  
Wear Behavior ◽  
Water Repellency ◽  
Innovative Technology ◽  
Water Repellent ◽  
High Catalytic Activity ◽  
Performance Study

The catalytic properties of nano-TiO2 modified fabric suits the demand for self-cleaning in recent years. In this paper, advanced and innovative technology were used to synthesize water sol of titanium dioxide photocatalyst with high catalytic activity for fabric finishing. The wear behavior, antibacterial property and water repellency of treated and untreated fabric were tested. Results indicate that finishing and washing of the titanium dioxide had no effect on wear behavior; finished and washed fabric has a certain antibacterial and water repellent properties.

scholarly journals Water repellency of clay, sand and organic soils in Finland

2008 ◽  
Vol 16 (3) ◽  
pp. 267 ◽  
Author(s):  
K. RASA ◽  
R. HORN ◽  
M. RÄTY
Keyword(s):  
Preferential Flow ◽  
Management Practice ◽  
Soil Surface ◽  
Water Repellency ◽  
Organic Soil ◽  
Water Infiltration ◽  
Organic Soils ◽  
Water Repellent ◽  
Moisture Regime ◽  
Wetting Process

Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

Investigation of sewing and water repellent performance of outdoor clothing

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yaşar Erayman Yüksel ◽  
Yasemin Korkmaz
Keyword(s):  
Design Methodology ◽  
Water Resistance ◽  
Water Repellency ◽  
Woven Fabrics ◽  
Water Repellent ◽  
Content Type ◽  
Textile Materials ◽  
Sewing Threads ◽  
Reduced Water ◽  
Seam Pucker

Purpose Durability of textile materials under wet conditions has become very important in recent years. The water repellency performance of fabrics should be maintained in the seam areas. The purpose of this paper is to analyze the effect of water repellent agents and sewing threads on the seam and water repellency performance properties of woven fabrics. Design/methodology/approach 100 percent polyester woven fabrics were treated with three different water repellent finishing agents (silicone, fluorocarbons with 6 and 8 carbons) and then sewn with different sewing threads (unfinished/water repellent finished polyester/cotton corespun and polyamide filament). Afterwards, mechanical properties, seam performance and water repellency properties of these materials were measured. Findings The effect of finishing which was statistically significant on seam strength only in warp direction was significant on seam elongation and efficiency in both warp and weft directions. Seam strength, seam efficiency, seam slippage and seam pucker of fabrics sewn with polyamide threads were higher than others. The fluorocarbons applied to the fabrics gave higher water repellency values than silicones. In addition, as the chain length increased in fluorocarbons, water repellency performance increased. Sewing process reduced water resistance of fabrics; however, water repellent finish applied to the threads increased water resistance of fabrics. Originality/value As a result of the literature review, it was seen that water repellency property of a wear were studied in only seamless areas of fabrics. Originality of this study is that the water repellency properties are also analyzed in the seam areas of the fabrics and evaluated together with the seam performance characteristics.

Preparation of organic–inorganic hybrid methylene blue polymerized organosilane/sepiolite pigments with superhydrophobic and self-cleaning properties

2019 ◽  
Vol 89 (19-20) ◽  
pp. 4220-4229 ◽  
Author(s):  
Shengtao Wu ◽  
Jinliang Huang ◽  
Haishuai Cui ◽  
Tian Ye ◽  
Fang Hao ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Natural World ◽  
Shielding Effect ◽  
Water Repellent ◽  
Inorganic Hybrid ◽  
Lotus Leaf ◽  
Spider Web ◽  
Chemical Inertness ◽  
Optical Stability ◽  
Self Cleaning

Inspired by the self-cleaning and water-repellent properties of the lotus leaf in the natural world, a kind of organic–inorganic hybrid pigment with superhydrophobic properties was prepared by adsorption of cationic methylene blue (MB) azo dyes onto acid-treated sepiolite (SEP), and then a superhydrophobic functional group of polymerized organosilanes (POSs) obtained from hexadecyltrimethoxysilane (HDTMS) and tetraethoxysilane (TEOS) was introduced onto the composite pigments (MB/SEP). The excellent chemical, thermal and optical stability of MB@POS/SEP are due to the shielding effect caused by the chemical inertness of the POS sheet. Furthermore, the superhydrophobic MB@POS/SEP pigments show an extraordinary self-cleaning property, which is similar to the waterproof property of the lotus leaf and spider web. The superhydrophobicity is strongly linked to their chemical composition and morphology, which can be adjusted by varying the concentration of HDTMS and TEOS. This kind of superhydrophobic pigment can be applied in various fields, such as ceramics, building and daily necessities.

Bio-Inspired Advanced Materials for Reducing Friction & Wear in MEMS Devices

2012 ◽  
Vol 545 ◽  
pp. 359-363 ◽  
Author(s):  
Ramachandra Arvind Singh ◽  
Nalam Satyanarayana ◽  
Sujeet Kumar Sinha
Keyword(s):  
Friction Force ◽  
Thick Films ◽  
Cost Effective ◽  
Small Scale ◽  
Water Repellent ◽  
Oxygen Plasma Treatment ◽  
Mems Devices ◽  
Textured Surfaces ◽  
Lotus Effect ◽  
Lotus Leaf

Micro-Electro-Mechanical-Systems (MEMS) are miniaturized devices built at micro/nano-scales. At these scales, friction force is extremely strong as it resists the smooth operation and reduces the useful operating lifetimes of MEMS actuator devices. In order to reduce friction and wear in MEMS devices, we have undertaken a bio-inspired approach by applying the underlying principle of the “Lotus Effect”. Lotus leaf surfaces have small-scale protuberances and wax covered on them, which make the surfaces water-repellent in nature. By creating textured surfaces that mimic these bio-surfaces, surface energy and contact area can be reduced. This in turn reduces friction force and eventually increases the wear durability of surfaces. In our work, we have fabricated bio-inspired surfaces that resemble the texture on lotus leaf. The method includes oxygen plasma treatment of polymeric thin/thick films and application of a nanolubricant namely, perfluoropolyether (PFPE). When this method was applied to SU8 polymer thin/thick films spin coated on silicon wafers, friction reduced considerably, and simultaneously the wear durability increased by >1000 times. The method is time and cost effective, and is commercially viable.

Sign in / Sign up

Export Citation Format

Share Document