Degree Of Contact Angle Research Articles

Investigation on comfort and water repellant properties of the Rtv-2 (Bi-component room temperature vulcanizing silicone) silicone coated woven fabric

The main goal of the study is to be obtained water repellant properties of woven fabric coated by Bi-Component Room Temperature Vulcanizing Silicone (RTV-2 silicone) and investigate the physical and thermal properties of these fabrics. In addition, the interaction between calendaring, sanforizing processes, which were known as mechanical finishing treatments, and RTV-2 coating application was investigated in terms of fabric physical performance. According to these experimental results, the possibility of the RTV-2 type silicone as alternative to C6 and C8 based fluorocarbon can be discussed. In this experiment, the woven fabric was coated by RTV-2 silicone with two different coating thickness (0.6 mm and 0.8 mm). The effect of the RTV-2 silicone onto woven fabric were examined and enlightened by physical performance and water repellence tests such as contact angle degree and spray rating tests. The results from contact angle degree and spray rating test pointed out that RTV-2 silicone coated fabric had up to 153.27° contact angle degree and ISO 3 (80) spray rating value whereas untreated fabric had 85.81° contact angle degree and 0 spray rating value. Thermal comfort test (ALAMBETA) showed that, thermal capacity value of the fabric decreased from 0.064 mm2/s to 0.040 mm2/s after RTV-2 silicone coating. On the other hand, thermal absorptivity value of the fabric increased from 117.25 to 234.95 W.%s/m2.K which leaded to increase the cold feeling of the fabric after coating RTV-2 silicone regardless of coating thickness and mechanical finishing processes. Photos from the textile surfaces were taken via Field Emission Scanning Electron Microscope (FE-SEM). It was obviously seen surface morphology after coating and mechanical finishing processes. At the end of the study, it was determined that it is possible to say that RTV-2 silicone usage can positively affect water repellant properties of the fabric while thermal comfort and tactile comfort properties is negatively affected. Fabric performance test such as pilling, abrasion resistance and color fastness to washing did not showed any change after RTV-2 silicone coating and mechanical finishing processes. As for the mechanical finishing processes interaction between RTV-2 silicone, it was seen that the RTV-2 silicone was affected by finishing processes.

Electrochemical Study of a Hydrophobic Film of γ-Al2O3/Hdtms on Low Carbon Steel

The corrosion phenomenon affects several low carbon steel structures leading to excessive expenditure on coatings and other alternatives. However, the coatings used usually contain compounds that pollute the environment. Therefore, environmentally friendly, economical and transparent coatings or films have been developed. The sol-gel method is a reliable way for the development of anticorrosive films, as is the case of alumina or silica films. In this work, the protective capacity of an alumina/HDTMS film was studied. The alumina film was sintered at 350, 450 and 550 °C and then the 1% HDTMS film was deposited. The protective ability of the γ-Al2O3/HDTMS film was evaluated by Electrochemical Impedance Spectroscopy (EIS) and Potenciodynamic Polarization Curves (PDP). The electrochemical results showed that the Al2O3/HDTMS film provided better protection compared to the metallic substrate. The contact angle degree was measured and determined that the sintered alumina/HDTMS films showed hydrophobic and superhydrophobic properties.

The effect of feed enzymes phytase, protease and xylanase on pelleting of microalgal biomass

Lower energy consumption for producing feed pellets is an important part of the economy in the feed mill. The same is if physical pellet quality is degraded. The interest in using of novel ingredients is increasing due to requirements for the sustainable development goals. Defatted microalgae as by-product from biodiesel production is one of many novel ingredients. The purpose of this experiment was to understand how the addition of small amount of enzymes can reduce the flow resistance in the die during pellet discharge, without affecting the physical quality of pellets. Thus, possibly reduce the total consumption of electrical energy during compaction. Three enzymes, phytase, protease, xylanase, and combinations of those were added to defatted Desmodesmus subspicatus microalgae at 3 inclusion levels. Feed enzymes xylanase and phytase helped lowering the flow resistance of the material in the die. Reduction of flow resistance was in average 17 times lover when all three levels of enzyme phytase were used. The same was observed when 0.01% xylanase was added. All feed enzymes and their combination have evidently lowered underwater pellet swelling due to their hydrolytic activity at the surface of the microalgal particles. The hydrolytic activities of the feed enzymes did not affect hardness of the microalgal pellets. Contact angle degree between pellet surface and oil droplet was lowered when xylanase and protease was used at all three dosage levels. However, contact angle degree between pellet surface and water droplets was unaffected by the hydrolytic activity of enzymes.

The Feed Enzymes Phytase, Protease and Xylanase Affect Pressure at Initial Flow and Do Not Affect Technical Properties During Pelleting of Microalgal Biomass

Lower energy consumption for producing feed pellets is an important part of the economy in the feed mill. The same is if physical pellet quality is degraded. The interest in using of novel ingredients is increasing due to requirements for the sustainable development goals. Defatted microalgae as by-product from biodiesel production is one of many novel ingredients. The purpose of this experiment was to understand how the addition of small amount of enzymes can reduce the flow resistance in the die during pellet discharge, without affecting the physical quality of pellets. Thus, possibly reduce the total consumption of electrical energy during compaction. Three enzymes, phytase, protease, xylanase, and combinations of those were added to defatted Desmodesmus subspicatus microalgae at 3 inclusion levels. Feed enzymes xylanase and phytase helped lowering the flow resistance of the material in the die. Reduction of flow resistance was in average 17 times lover when all three levels of enzyme phytase were used. The same was observed when 0.01% xylanase was added. All feed enzymes and their combination have evidently lowered underwater pellet swelling due to their hydrolytic activity at the surface of the microalgal particles. The hydrolytic activities of the feed enzymes did not affect hardness of the microalgal pellets. Contact angle degree between pellet surface and oil droplet was lowered when xylanase and protease was used at all three dosage levels. However, contact angle degree between pellet surface and water droplets was unaffected by the hydrolytic activity of enzymes.

Synthesis, Physical Properties and Enzymatic Degradation of Biodegradable Nanocomposites Fabricated Using Poly(Butylene Carbonate-Co-Terephthalate) and Organically Modified Layered Zinc Phenylphosphonate.

A new biodegradable aliphatic-aromatic poly (butylene carbonate-co-terephthalate) (PBCT-85) with the molar ratio [BC]/[BT] = 85/15, successfully synthesized through transesterification and polycondensation processes, was identified using 1H-NMR spectra. Various weight ratios of PBCT/organically modified layered zinc phenylphosphonate (m-PPZn) nanocomposites were manufactured using the solution mixing process. Wide-angle X-ray diffraction and transmission electron microscopy were used to examine the morphology of PBCT-85/m-PPZn nanocomposites. Both results exhibited that the stacking layers of m-PPZn were intercalated into the PBCT-85 polymer matrix. The additional m-PPZn into PBCT-85 copolymer matrix significantly enhanced the storage modulus at −70 °C, as compared to that of neat PBCT-85. The lipase from Pseudomonas sp. was used to investigate the enzymatic degradation of PBCT-85/m-PPZn nanocomposites. The weight loss decreased as the loading of m-PPZn increased, indicating that the existence of m-PPZn inhibits the degradation of the PBCT-85 copolymers. This result might be attributed to the higher degree of contact angle for PBCT-85/m-PPZn nanocomposites. The PBCT-85/m-PPZn composites approved by MTT assay are appropriate for cell growth and might have potential in the application of biomedical materials.

Use of sea urchin spines with chitosan gel for biodegradable film production

In recent years, the film production from natural polymers has considerably increased in food industry as an alternative to the petroleum based synthetic films. Chitosan is one of the most preferred biopolymers for bio-based film production, due to its biocompatibility, biodegradability, antioxidant activity and antimicrobial properties. Because of its hydrophilic properties, chitosan based films dissolve in water, limiting its uses in industry, to overcome this problem; we mixed 200 and 400 mg of the sea urchin spine powder (SUSP) with 20 mL chitosan gel respectively, to obtain a hydrophobic film. The chitosan films prepared with 200 mg SUSP showed a rise in the degree of contact angle from 70.2° to 107° providing hydrophobicity properties. On the other hand, addition of 400 mg of SUSP to chitosan film resulted in a contact angle of 96.1°. Moreover, the antioxidant activity and thermal stability of the films were increased in the presence of SUSP. Fourier Transform Infrared Spectrophotometry results proved the interactions between chitosan and SUSP. Chitosan films have smooth surface while SUSP blended films have rough surface morphology. These results demonstrated that SUSP is needed to improve the properties of chitosan films for usage in food industry.

Nanolayer Film on Poly(Styrene/Ethylene Glycol Dimethacrylate) High Internal Phase Emulsion Porous Polymer Surface as a Scaffold for Tissue Engineering Application

Highly open, porous polymer or poly(high internal phase emulsion) (polyHIPE) obtained from polymerized high internal phase emulsions (HIPE) have recently attracted much attention and increasing interest in tissue engineering applications because of their excellent properties. This research is aimed at preparing and developing a process for producing polyHIPE for use as a scaffold in tissue engineering applications. Poly(styrene/ethylene glycol dimethacrylate) (poly(S/EGDMA)) loaded with hydroxyapatite was used to prepare the polyHIPE. Further improvement on hydrophilicity and biological response to tissue fluids of the polyHIPE porous polymer was carried out using a nanolayer coating via the layer-by-layer polyelectrolyte multilayer (PEM) technique. Three types of chemicals were used for coating on the surface of the polyHIPE porous polymer such as poly(sodium 4-styrene sulfonate) (PSS), gelatin (GEL), and alginic acid (ALG). The change in surface properties of the modified poly(S/EGDMA)HIPE was characterized by UV-visible spectroscopy and contact angle measurement. Further assessments consisted of cytotoxicity testing, cell attachment, and proliferation of L929, fibroblast-like cells that were seeded on the surface of the polyHIPE porous polymer. A three-dimensional structure poly(S/EGDMA)HIPE porous polymer with high porosity was successfully prepared. Moreover, it was found that surface modification encouraged poly(S/EGDMA)HIPE with a hydrophilic nanolayer, as observed by the decrease in contact angle degree and cell adhesion of L929 fibroblast-like cells, indicating that the poly(S/EGDMA)HIPE porous polymer was effectively improved by using the layer-by-layer technique. It was revealed by MTT assay that the poly(S/EGDMA)HIPE porous polymer coated with a nanolayer of a polyelectrolyte multilayer led to an enhancement in the amount of cell adhesion and proliferation on the modified poly(S/EGDMA)HIPE porous polymer. Additionally, the most effective polyelectrolyte solution for improving cell adhesion of the poly(S/EGDMA)HIPE was PSS.

Investigation and Characterization of Plasma-Treated Poly(3-hydroxybutyrate) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Biopolymers for an In Vitro Cellular Study of Mouse Adipose-Derived Stem Cells.

Polyhydroxyalkanoates (PHAs) are a type of thermoprocessable and biodegradable polyester, which represent a potential sustainable replacement for fossil-fuel synthetic polymers, such as polypropylene and polyethylene. In recent years, copolymers of PHAs, i.e., poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), have received attention for medical and packaging industrial applications, due to their biodegradable, toxic-free, and biocompatible nature. This study investigated and characterized plasma-treated PHB and PHBV films fermented with Ralstonia eutropha H16. The X-ray photoelectron spectroscopy (XPS) and water contact angle analyses on the plasma-treated PHB and PHBV film surfaces revealed an increase in the number of functional groups and contact angle degree, respectively, compared to that of the untreated films. In addition, an in vitro experiment of mouse adipose-derived stem cells showed better growth and adhesion of the cells on the surface of plasma-treated PHBV film. Overall, these results reveal that plasma surface modifications are useful in biomaterial development.

SYNTHESIS AND CHARACTERISATION OF ELECTROSPUN CHITOSAN MEMBRANES REINFORCED BY HALLOYSITE NANOTUBES

We report on the electrospinning method to synthesize and characterise chitosan membranes reinforced by halloysite nanotubes (HNTs). The synthesis process addressed two levels of HNTs concentration, i.e., 2 and 5 wt.%. Tensile testing was carried out to determine the strength (σ), strain (ε) at σ and elastic modulus (E) of the membranes. Tensile test data revealed that the membranes reinforced with 5 wt.% HNTs yielded the highest E (0.153 ± 0.02 GPa) and strength (22.53 ± 8.57 MPa). Electron micrographs of the fractured surfaces showed uniform dispersions of HNTs in the chitosan matrix. Infrared spectra indicated interactions between chitosan and inner and outer surfaces of HNTs. Thermogravimetric analysis demonstrated an increase in thermal stability with the addition of HNTs. Membranes immersed in simulated body fluid system for 28 days revealed the formation of dense apatite blocks with the addition of HNTs. Surface roughness increased with the addition of HNTs resulted a rise in degree of contact angle.

Modeling, Simulation and Verification of Parameters Study on Flexible Automotive Wiper

This paper develops the mathematical expression of wiper system using Newtonian approach verified using a numerical approach adopted from open literatures. Result shows that the correlation for both methods is more than 90 percent and it is agreed to make a further analysis. Three parameters namely force, friction and contact angle were chosen to identify the performance of wiper system due to decrease the unwanted level of noise and vibration. Noise and vibration level are slightly decreased by applying the 4.7 Newton, 0.3 coefficient of friction and 12 degree of contact angle when the system is fully operated to wipe the rain and dust on the in front windscreen. These three types of parameters have potentials to avoid a visual and audible annoyance to driver and passenger during a raining condition.

Polymer Film Selection for Corrosion Protection of Data Storage Magnetic Materials

Due to the current requirement of high recording density of hard disk drive, the thickness of DLC layer which is the protective layer is needed to be reduced. Therefore, the corrosion of read-write elements that are fabricated from soft magnetic materials is more critical. During the photolithography process, polymer photoresist is playing the major role on controlling the corrosion of soft magnetic materials. Two different types of polymer photoresists are selected to investigate, noted as wet photoresist and dry photoresist, respectively. Contact angle measurement, AFM and SEM are techniques using to determine the quality of polymer photoresists. Furthermore, the direct corrosion is also studied by using potentiostat/galvanostat-based measurements. The result suggested that the wet photoresist, AZ4999 Clariant, is better as compared to that of dry photoresist. No surface degradation as well as surface defects of the wet photoresist was found after lithography process. The corrosion rate of the specimen coated by this corresponding wet film is found to be only 1.44 x 10(-6) mm/y. In addition, the wet photoresist surface is hydrophobic posed of more than 75 degree of contact angle.

Einflu� von Benetzungsspannung und lonen auf die Substratbesiedlung und das Einsetzen der Metamorphose bei Bryozoenlarven (Bowerbankia gracilis)

Settlement and metamorphosis in larvae of Bowerbankia gracilis depend on the wettability of the substratum. The wettability of a solid can be characterized by it's specific contact angle, ϑ. Larvae settle on solids with angles >17°, but not on surfaces with high wettability properties. In an attempt to explain this phenomenon, we consider the larvae as a second liquid and their attachment as a second wetting. In such case, water and larvae would compete in wetting the substratum. Adhesion can be accounted for by assuming the wetting tension of solid to water to be lower than that of the larval surface (|σsolid/water| < |σsolid/larvae|). Adhesion would thus be favoured energetically. The rate of settlement and that of metamorphosis are demonstrated as depending on the degree of contact angle, ϑ, in an all-or-none fashion. Settlement of larvae on high-wetting solids is prevented by high capillary pressure accruing at the point of contact. Metamorphosis is initiated by contractions occurring after adhesion. Application of CsCl or KCl induces such contractions and metamorphosis in free-swimming larvae. MgCl2 prevents the onset of metamorphosis but not adhesion. Two mechanisms are considered as possibly accounting for induction of metamorphosis: (1) mechanical stimulation by shearing the cilia at the point of contact, and (2) a chemical stimulation of the cell membrane after application of K+ or Cs+.