scholarly journals Adhesion and running speed of a tropical arboreal ant ( Cephalotes atratus ) on wet substrates

2018 ◽  
Vol 5 (11) ◽  
pp. 181540 ◽  
Author(s):  
Alyssa Y. Stark ◽  
Stephen P. Yanoviak
Keyword(s):  
Forest Canopy ◽  
Normal Force ◽  
Running Speed ◽  
Water Contact ◽  
Static Water Contact Angle ◽  
Static Water ◽  
Normal Adhesion ◽  
Substrate Types ◽  
Tropical Forest Canopy ◽  
Adhesive Performance

In the tropical forest canopy, wingless worker ants must cling to and run along diverse vegetative surfaces with little protection from sun, wind and rain. Ants rely in part on their tiny adhesive tarsal pads to maintain sufficient contact with substrates to prevent falls under these varied conditions. Here, we examined the effects of substrate wettability and surface water on the tarsal pad adhesive performance of a common tropical arboreal ant. Ant adhesion was consistently higher on an intermediately wetting substrate (static water contact angle ca 90°) when resisting both perpendicular (normal) force and parallel (shear) force. Normal adhesion was maintained on intermediately wetting and hydrophobic substrates following the addition of rain-mimicking water droplets, whereas shear adhesion declined on all substrate types tested after wetting. Ant running speed was slower on wet substrates. On wood substrates, normal and shear adhesion declined with increasing wetness from dry, to misted, to water-soaked. These differences probably contributed to lower ant running speed on wet wood. The results of this study provide the first quantitative assessment of tropical arboreal ant adhesive performance under substrate conditions that are commonly encountered in the rainforest canopy.

scholarly journals Development of Superhydrophobic Polyester (Polyethylene terephthalate) Fabric for Multiple Applications

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Subhas Ghosh ◽  
Roopkatha Pallye
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Polyester Fabric ◽  
Ftir Analysis ◽  
Water Contact ◽  
Abrasion Test ◽  
Static Water Contact Angle ◽  
Static Water ◽  
Polyester Textile ◽  
Textile Fabric

This study intended to develop a healthy and environmentally friendly super-hydrophobic PET polyester textile fabric using a specific Fluoro Silane finish (SHF). A novel SHF was prepared and applied on a polyester fabric using a pad-dry-cure method. The finished fabric was evaluated for the degree of hydrophobicity, durability and stain repellence. The finished fabric exhibited static water contact angle greater than 170o and received 90 AATCC (4 ISO) rating that is recognized as super-hydrophobicity and this property was maintained even after a 50,000-cycle abrasion test. FTIR analysis identified the characteristic peaks related to Si-O-Si and C-F asymmetric stretching bands of the finish on the fabric indicating a robust attachment on the fabric. Finished fabric did not show any change in appearance or tactile characteristics of the fabric. 

Antigen detection with thermosensitive hydrophilicity of poly(N-isopropylacrylamide)-grafted poly(vinyl chloride) fibrous mats

2018 ◽  
Vol 6 (21) ◽  
pp. 3486-3496 ◽  
Author(s):  
Jian-Wei Guo ◽  
Zhen-Yu Lin ◽  
Bohr-Ran Huang ◽  
Chien-Hsing Lu ◽  
Jem-Kun Chen
Keyword(s):  
Contact Angle ◽  
Vinyl Chloride ◽  
Water Contact Angle ◽  
Antigen Detection ◽  
Stimuli Responsive ◽  
Water Contact ◽  
Static Water Contact Angle ◽  
Poly Vinyl Chloride ◽  
Static Water

The static water contact angle of stimuli-responsive fibrous mats is used as a convenient index for rapid antigen detection.

scholarly journals Bio-Based Coatings for Food Metal Packaging Inspired in Biopolyester Plant Cutin

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 942 ◽  
Author(s):  
José J. Benítez ◽  
Sonja Osbild ◽  
Susana Guzman-Puyol ◽  
Antonio Heredia ◽  
José A. Heredia-Guerrero
Keyword(s):  
Tin Oxide ◽  
Structural Modification ◽  
Thick Layer ◽  
Cleavage Reaction ◽  
Promoting Effect ◽  
Water Contact ◽  
Naturally Occurring ◽  
Static Water Contact Angle ◽  
Static Water ◽  
Aleuritic Acid

Metals used for food canning such as aluminum (Al), chromium-coated tin-free steel (TFS) and electrochemically tin-plated steel (ETP) were coated with a 2–3-µm-thick layer of polyaleuritate, the polyester resulting from the self-esterification of naturally-occurring 9,10,16-trihydroxyhexadecanoic (aleuritic) acid. The kinetic of the esterification was studied by FTIR spectroscopy; additionally, the catalytic activity of the surface layer of chromium oxide on TFS and, in particular, of tin oxide on ETP, was established. The texture, gloss and wettability of coatings were characterized by AFM, UV-Vis total reflectance and static water contact angle (WCA) measurements. The resistance of the coatings to solvents was also determined and related to the fraction of unreacted polyhydroxyacid. The occurrence of an oxidative diol cleavage reaction upon preparation in air induced a structural modification of the polyaleuritate layer and conferred upon it thermal stability and resistance to solvents. The promoting effect of the tin oxide layer in such an oxidative cleavage process fosters the potential of this methodology for the design of effective long-chain polyhydroxyester coatings on ETP.

scholarly journals Superhydrophobic Surface with Gamma Irradiation Resistance and Self-Cleaning Effect in Air and Oil

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 106 ◽  
Author(s):  
Yan Zhang ◽  
Jing Zhang ◽  
Yujian Liu
Keyword(s):  
Superhydrophobic Surface ◽  
Water Repellency ◽  
Sio2 Nanoparticles ◽  
Superior Performance ◽  
Sliding Angle ◽  
Water Contact ◽  
Composite Surface ◽  
Static Water Contact Angle ◽  
Static Water ◽  
Dirt Removal

A superhydrophobic surface was synthesized by a combination of an epoxy/polymethylphenylsiloxane matrix and dual-scale morphology of silica (SiO2) nanoparticles. When the amount of SiO2 reached 30 wt.%, the as-prepared surface showed a high static water contact angle (WCA) of 154° and a low sliding angle (SA) of 5°, excellent water repellency, and dirt-removal effects both in air and oil (hexamethylene). Even after exposure to as high as a 12.30 Mrad dose of gamma-rays, the composite surface still maintained its superior performance.

scholarly journals Study of the Properties of the Porous Silicon Synthesized by Ag Assisted Chemical Etching

2016 ◽  
Vol 71 ◽  
pp. 40-48 ◽  
Author(s):  
Madhavi Karanam ◽  
G. Mohan Rao ◽  
Shaik Habibuddin ◽  
R. Padmasuvarna
Keyword(s):  
Porous Silicon ◽  
Etching Time ◽  
Photoluminescence Spectra ◽  
Hydrophobic Properties ◽  
Water Contact ◽  
Optical Absorbance ◽  
Angle Measurements ◽  
Static Water Contact Angle ◽  
Contact Angle Measurements ◽  
Static Water

Porous Silicon (PSi) is synthesized by Ag assisted electroless etching and characterized by Scanning electron microscopy (SEM). The effect of etching time on the optical reflectivity, optical absorbance of PSi is investigated. Reflectivity measurements showed that 45% reflectivity Si wafers drops from 45% to 10% for 2 hours etching and 6% for 3 hours etching. The decrease in the reflectivity shows that the PSi can be employed as an anti reflecting substrate in optoelectronic devices. The absorbance measurements reveal that the average absorbance of PSi is 0.60 in the wavelength range 300-800 nm after 2 hours etching. From the photoluminescence spectra it was found that PL intensity of PSi is high compared to bare silicon wafer. Static water contact angle measurements were performed to examine the hydrophobic properties of the PSi prepared under different conditions.

Hydrophobic Zinc Oxide Nanocomposites for Consolidation and Protection of Quartzite Sculptures: A Case Study

2020 ◽  
Vol 63 ◽  
pp. 64-75
Author(s):  
Yasser Kamal Hefni
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Archaeological Sites ◽  
Oxide Nanoparticles ◽  
Direct Role ◽  
Water Contact ◽  
Static Water Contact Angle ◽  
Static Water ◽  
Physical And Chemical

Quartzite sculptures are considered some of the most impressive and informative archaeological remains which have been found in the most of Egyptian archaeological sites. Regrettably, quartzite sculptures suffer from many deterioration aspects such as granular disintegration, scaling, cracking, efflorescence, soiling, microbiological colonization. Water is the main aggressive deterioration factor of stones and stone-based monuments, as in addition to its direct role in deterioration mechanisms, it plays as a catalyst in the physicochemical and microbiological deterioration processes.During the last two decades, polymer nanocomposites have widely been applied in the field of cultural heritage conservation due to their unique physical and chemical characteristics. Zinc oxide nanoparticles are among the most important semiconductive nanomaterials that have been applied in the fabrication of nanocomposites. They have been demonstrated to improve the physicochemical and mechanical properties of polymers. In addition, zinc oxide nanoparticles were mixed with polymers in order to fabricate superhydrophobic and self-cleaning protective materials.The aim of this paper is to evaluate the efficiency of zinc oxide nanocomposites, in order to select the best of them for the consolidation and protection of a colossal quartzite statue of Ramesses II. The properties of the treated quartzite samples were comparatively examined by colourimetric measurements, static water contact angle, compressive strength, and scanning electron microscope.

Fabrication of a Superhydrophobic Aluminum Alloy Surface by Phosphoric Acid-Dichromate Method

2013 ◽  
Vol 312 ◽  
pp. 350-353
Author(s):  
Ruo Mei Wu ◽  
Guang Hua Chao ◽  
Hai Yun Jiang
Keyword(s):  
Aluminum Alloy ◽  
Phosphoric Acid ◽  
Superhydrophobic Surface ◽  
Preparation Method ◽  
Sliding Angle ◽  
Water Contact ◽  
Static Water Contact Angle ◽  
Static Water ◽  
Acid Coating ◽  
Aluminum Alloy Surface

The preparation method of the superhydrophobic surface on aluminum alloys was investigated, the method is novel by phosphoric acid-dichromate process and stearic acid coating, superhydrophobic aluminum alloy surfaces were successful prepared, the maximum static water contact angle and sliding angle on the superhydrophobic surface was 151±1.8° and 10°, respectively. In this work, the microstructure and self-cleaning properties of the superhydrophobic surface were studied. The superhydrophobic surface is a factor to reduce device-associated contamination and can be used in metal packaging practice.

On Antireflective Coatings with Stable Hydrophobicity for Solar Tube

2013 ◽  
Vol 423-426 ◽  
pp. 443-447 ◽  
Author(s):  
Wen Wen Dou ◽  
Yu Chao Niu ◽  
Xiang Ju Liu ◽  
Xiao Li Wang ◽  
Yong Xu
Keyword(s):  
Contact Angle ◽  
Low Temperature ◽  
Water Contact Angle ◽  
Prolonged Exposure ◽  
Sol Gel ◽  
High Porosity ◽  
Antireflective Coatings ◽  
Water Contact ◽  
Static Water Contact Angle ◽  
Static Water

Antireflective coatings with stable hydrophobicity for solar tube were prepared via sol-gel method and hexamethyldisilazane (HMDS) treatment. The coatings have a high porosity, groove-like surface morphology and a big static water contact angle. As a result, the coatings exhibit high transmittance even in high humidity environments. The transmittance peak can reach up to 99.02% which increased by 7% compared with the substrate and the wavelength band increased by more than 5% is from 438nm to 1000nm. After prolonged exposure to strong ultraviolet (UV) irradiation, the static water contact angle of the HMDS treated antireflective coatings decreased very small from 102o to 98o. In addition, the low-temperature tests showed the contact angle did not decline even at-50°C. The results suggest that the coatings prepared in present paper have stable hydrophobic and antireflective performance in the environment of strong UV radiation and low temperature.

FACILE SYNTHESIS OF SUPER HYDROPHOBIC MATERIAL FOR SELECTIVE REMOVAL OF SPILLED-OIL FROM WATER SURFACES

2016 ◽  
Vol 2 (2) ◽  
pp. 74-77
Author(s):  
Manoj Patowary ◽  
Khanindra Pathak
Keyword(s):  
High Selectivity ◽  
Selective Removal ◽  
Polluted Water ◽  
Synthetic Approach ◽  
Water Contact ◽  
Static Water Contact Angle ◽  
Static Water ◽  
One Step ◽  
Spilled Oil ◽  
Hydrophobic Material

The present work reports the preparation of super hydrophobic and oleophilic sorbent powder for the selective removal of spilled-oil from oil-polluted water surface. The sorbent powder was prepared by the surface modification of commercially available pure barium sulfate (BS) with palmitic acid via a simple one-step synthetic approach. The powder was observed to exhibit super hydrophobic character with a static water contact angle value of 152±2°. The powder also possesses sufficient buoyancy and exhibits high selectivity towards oil, vital for a sorbent for use in oil spill clean-ups. The oil sorption capacity of the sorbent material was also investigated.

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