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A surfactant-assisted electric breath figure method, SAEBF, was applied to form the polysulfone, PSF, film. Experimentally, the sodium dodecyl-benzenesulfonate, SDDBS, was employed and the voltage was varied. FESEM images showed that the SAEBF formed PSF films have the honeycomb structure and the pore diameter was reduced with the applied voltage increase. Water contact angle on the honeycomb PSF film surfaces was found to increase with the applied voltage increase and there has a critical voltage at about 0.6 kV among those applied voltages because the applied voltage at lower or higher caused the film surface in hydrophilic or hydrophobic, respectively. A related mechanism was discussed. [ABSTRACT FROM AUTHOR]

This work presents an application of the evolutionary structural optimization (ESO) method to optimize two of the most common bonded joints – the single lap joint and the double lap joint. The ESO method was used to shape the adherends contour to reduce peak stresses at the overlap ends. The shape optimization was performed under a von Mises rejection criterion. The von Mises stress was evaluated using the finite element model for both types of joints. It is proposed here to utilize a honeycomb-like mesh using hexagonal elements to minimize stress concentration problem. Additionally, the use of a honeycomb mesh in the ESO method led to a smoother adherend contour. Numerical results show how the stress distributions for both shear and peel stresses are improved after the application of this optimization method. [ABSTRACT FROM PUBLISHER]

Surface wettability is a significant factor in determining the physical and chemical properties of materials. It is known that both the chemical properties of the surface and its topography play important roles. A honeycomb-structured polymer film can be prepared by casting a hydrophobic polymer solution under humid conditions. Here, we measured water repellency on the honeycomb- and pincushion-structured films of various kinds of hydrophobic polymers. We show that the honeycomb- and pincushion-structured films of hydrophobic polymers have high water repellent properties. Especially, the water contact angles on pincushion-structured films are over 130°. From the results of these experiments, it appears that the surface structures prepared by self-organization process enhance the hydrophobicity of the surface. An easy process for creating highly water repellent surfaces is required to utilize these surfaces in industrial applications. Thus, the simple self-organization process has advantages from the standpoint of application. [ABSTRACT FROM AUTHOR]