A pore-size tunable superhydrophobic membrane for high-flux membrane distillation

Membrane distillation (MD) has recently attracted attention as a promising solution to the freshwater crisis. We report a pore-size tunable superhydrophobic membrane for application in the MD process. The tuning of the pore size is accomplished by applying mechanical strain to the stretchable superhydrophobic (SS) membrane. The SS membrane was made using a simple fabrication process that involved electrospinning and electrospraying. Various parameters of the membrane, including the pore size, the pore-size distribution, the contact angle, and the liquid entry pressure, were tested while mechanical strains were applied. The SS membrane was used in direct contact membrane distillation. The MD performance of the membrane, according to the applied mechanical strain, was studied, and the optimal strain applied was determined in terms of the permeate flux, the rejection rate, and the membrane longevity. As anticipated, increasing the pore size of the membrane enhanced the permeate flux. With the optimal mechanical strain, the SS membrane exhibited one of the highest permeate flux values ever reported at 36.5 L/m(2)h and stable permeate conductivity for a transmembrane temperature of 40 degrees C (3.5 wt% NaCl salt feed) over 5 h of MD operation. Furthermore, the MD performance of the SS membrane, according to the applied mechanical strain, was theoretically studied through computing simulation and was compared to the experimental results. The pore-size tunable superhydrophobic membrane presented in this study would provide a means of exploring what type of impact the membrane pore size has in MD both experimentally and theoretically.11Nsciescopu

One-Step Laser Encapsulation of Nano-Cracking Strain Sensors

Development of flexible strain sensors that can be attached directly onto the skin, such as skin-mountable or wearable electronic devices, has recently attracted attention. However, such flexible sensors are generally exposed to various harsh environments, such as sweat, humidity, or dust, which cause noise and shorten the sensor lifetimes. This study reports the development of a nano-crack-based flexible sensor with mechanically, thermally, and chemically stable electrical characteristics in external environments using a novel one-step laser encapsulation (OLE) method optimized for thin films. The OLE process allows simultaneous patterning, cutting, and encapsulating of a device using laser cutting and thermoplastic polymers. The processes are simplified for economical and rapid production (one sensor in 8 s). Unlike other encapsulation methods, OLE does not degrade the performance of the sensor because the sensing layers remain unaffected. Sensors protected with OLE exhibit mechanical, thermal, and chemical stability under water-, heat-, dust-, and detergent-exposed conditions. Finally, a waterproof, flexible strain sensor is developed to detect motions around the eye, where oil and sweat are generated. OLE-based sensors can be used in several applications that are exposed to a large amount of foreign matter, such as humid or sweaty environments

Fabrication of Nanofiber Air Filter with Self-Cleaning through Superhydrophobic Bead Coating

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