17-08-2012, 03:23 PM
Polymer Nanofibrous Membrane and its Potential Applications
Polymer Nanofibrous Membrane .doc (Size: 94 KB / Downloads: 32)
When the diameters of polymer fiber materials are shrunk from micrometers to submicrons or nanometers,there appear several amazing characteristics such as very large surface area to volume ratio , flexibility in surface functionalities, and superior mechanical performance (e.g. stiffness and tensile strength) compared with any other known form of the material. These outstanding properties make the polymer nanofibers to be optimal candidates for many important applications. A number of processing techniques such as drawing, template synthesis , phase separation , self-assembly , electrospinning , etc. have been used to prepare polymer nanofibers in recent years. Out of these techniques, electrospinning is the the only method which can be further developed for mass production of one-by-one continuous nanofibers from various polymers.
Filtration application
Since the channels and structural elements of a filter must be matched to the scale of the particles or droplets that are to be captured in the filter, one direct way of developing high efficient and effective filter media is by using nanometer sized fibers in the filter structure. Due to the very high surface area to volume ratio and resulting high surface cohesion, tiny particles of the order of <0.5 mm can be easily trapped in the electrospun nanofibrous structured filters and hence the filtration efficiency can be improved.
Protective cloathing applications
The protective clothing in military is mostly expected to help maximize the survivability, sustainability, and combat effectiveness of the individual soldier system against extreme weather conditions, ballistics, and NBC (nuclear, biological, and chemical) warfare. Current protective clothing containing charcoal absorbents has its limitations in terms of water permeability, extra weight-imposed to the article of clothing. Because of their great surface area, nanofiber fabrics are capable of the neutralization of chemical agents and without impedance of the air and water vapor permeability to the clothing. Electrospinning results in nanofibers laid down in a layer that has high porosity but very small pore size, providing good resistance to the penetration of chemical harm agents in aerosol form.
Wound dressing
Polymer nanofibers can also be used for the treatment of wounds or burns of a human skin. With the aid of electric field, fine fibers of biodegradable polymers can be directly sprayed/spun onto the injured location of skin to form a fibrous mat dressing, which can let wounds heal by encouraging the formation of normal skin growth and eliminate the formation of scar tissue which would occur in a traditional treatment. Non-woven nanofibrous membrane mats for wound dressing usually have pore sizes ranging from 500 nm to 1 micrometer, small enough to protect the wound from bacterial penetration via aerosol particle capturing mechanisms. High surface area of 5–100 m2/g is extremely efficient for fluid absorption and dermal delivery.