Ruo Mei Wu

Fabrication of a Super-Hydrophobic Micro-Nanoporous Aluminum Surface by Anodic Oxidation

A novel and stable super-hydrophobic film was prepared by stearic acid (C18H36O2), which was chemically adsorbed onto the anodized aluminum surface. The maximum static water contact angle (WCA) of the super-hydrophobic surface was 157.5º ± 2.0º and the contact angle hysteresis was less than 3º. The superhydrophobic property is attributed to the micro-nanoporous surface morphology and stearic acid. The pore size on the surface of anodic aluminum oxide is an important factor for controlling the superhydrophobic adhesiveness. The superhydrophobic surface is a factor to reduce device-associated infection and can be used in metal packaging practice.

Effects of Oxalic Acid and Sodium Chloride on the Superhydrophobic Surface on Aluminum Alloy by Anodizing and PP-Coating

We investigated the preparation of the superhydrophobic surface on aluminum alloy by anodizing and PP coating. The effects of oxalic acid and sodium chloride in the electrolytic cell on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was achieved by direct PP coating after anodizing. The addition of oxalic acid had a little enhanced effect on the superhydrophobic surface, while the addition of sodium chloride had an obvious effect on the superhydrophobic surface. When the concentration of NaCl was 1.25 g/L, the contact angle (CA) was up to 162 ° and the sliding angle was lower than 3 ° .

Anti-Icing Properties of Superhydrophobic poly (vinyl chloride) Coatings

In this work, the anti-icing properties of different poly (vinyl chloride) coatings with different wettabilities were investigated in a climatic chamber with a working temperature of −10 °C. Compared with smooth poly (vinyl chloride) coating, the superhydrophobic poly (vinyl chloride) coating with high sliding angle did not show obvious anti-icing property. However, the superhydrophobic poly (vinyl chloride) coating with low sliding angle can largely prevent ice formation on the surface, showing excellent anti-icing property.

Bacteriostasis of a Super-Hydrophobic Micro-Porous Aluminum Surface by a Facile Preparation Method

We investigated the bacteriostasis of the super-hydrophobic surface on aluminum alloy by PP coating. The morphology of the surface was observed by a scanning electron microscopy. The contact angle (CA) was measured by an optical contact angle meter .Staphylococcus aureus and pathogenic escherichia coli adhesion on superhydrophobic surfaces were also evaluated. The inhibition ring test results show the inhibition of Escherichia coli and Staphylococcus aureus were 79.3% and 81.1%, respectively after 24 hours’ contact at 37oC, while the Quinn test demonstrates the surface possesses high resistance to bacterial contamination. The superhydrophobic surface is a factor to reduce device-associated infection and can be used in metal practice.

Experimental Study on Composite Deformation of Drawing-Flanging for Axisymmetric Holed Slab

The experimental study on the influencing regularity of the technological parameters to the deformed tendency & the forming load during drawing forming axisymmetric holed slab was carried out. The influence of the pre-punched hole size, and punching stroke o n the deformed tendency & their r elation with the forming load were analyzed. Result of experiment can be used as basic consideration for the process design of drawing after hole punching and the techno logical measures to punch technological hole for releasing stress at the region difficult to form to improve the deformation degree.

Fabrication of Super-Hydrophobic Surface on Aluminum Alloy by a Simple Immersion Method

In order to improve the corrosion resistance property of the aluminum alloy surface, a simple chemical immersion method was developed for fabricating the super-hydrophobic surface on aluminum alloy. After treating the chemical etched surface using low surface energy material stearic-acid, the aluminum alloy surface exhibits a super-hydrophobic property with water contact angle of 154° and contact angle hysteresis of 7°. The surface morphology was inspected with scanning electron microscope, and it was found that the surface was configured in a labyrinth structure with convexity and caves of micro-nanostructure; this hierarchical micro-nanostructure plays an important role in the formation of the super-hydrophobic surface. The effects of the etching time and the etchant (potassium permanganate solution) concentration on the super-hydrophobic surface were investigated, and the optimum technical conditions are that etching the aluminum alloy in 0.1mol/L potassium permanganate solution concentration for 3 h. At the same time, we also studied the wettability of the aluminum alloy super-hydrophobic surface. The results showed that the super-hydrophobic aluminum alloy has good stability, corrosion resistance property and self-cleaning.

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

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.

Effects of Acid Concentration on the Superhydrophobic Surface on Aluminum Alloy by Etching and PP-Coating

We investigated the effect of hydrochloric acid concentration for preparing the superhydrophobic surface on aluminum alloy by etching and PP coating. The superhydrophobicity of the surface was characterized by water contact angle. The morphologies of the surface were observed by SEM. The results showed that the acid concentration had an obvious effect on the hydrophobic surface and a good superhydrophobic surface was achieved by PP coating after etching for suitable time. When the acid concentration is lower, the longer time is necessary for obtaining the superhydrophobic surface. When the concentration of hydrochloric acid was 4 g/L and the etching time was only 8 min, the best superhydrophobic surface with the highest contact angle (CA) of 157° was prepared. The obtained superhydrophobic surface resulted from the rough surface and the material of PP with the low surface energy.

Superhydrophobic Film Make up of Corrosion Aluminum Plates and Polypropylene Coated

Polypropylene (PP) film was used as coating to improve the hydrophobicity of corrosive aluminum surface. A micro-porous film with compound nanoparticles was obtained on the aluminum alloy substrate using the corrosion method and coated PP. The water contact angle (WCA) of superhydrophobic surface is 157°. The superhydrophobic property is attributed to this special surface morphology and low surface energy PP. Aggregated nanoparticles would help to increase the surface hydrophobicity.

Antibacterial Activity of Nano Silver and it’s Application in Antibacterial Paper

The antibacterial activity of nano silver against Escherichia coli was measured by the inhibition zone and minimal inhibitory concentrations. Results showed that the inhibition zone of nano silver was improved with the increase in concentration, and the MIC of nano silver was 15.6ppm. In addition, the antibacterial activity of the antibacterial paper was determined by inhibition zone method. The paper prepared by polyvinyl alcohol(PVA), sodium carboxymethylcellulose(CMC-Na) and starch adhesive had the greatest activity at a nano silver concentration of 400,800,600ppm respectively. The paper basis weight,tensile strength and elongation were all increased after coating.