Properties and applications of externally impregnated shaped fibers

Polymeric fibers have been produced in an array of geometric cross-sections, all of which possess deep channels along the length of the fiber. These shaped fibers have been made in many different formats including wovens, nonwovens, and parallel arrays. A number of polymeric materials are suitable to retain these nonround cross-sections during spinning; they include polyolefins, polyesters, and polyamides. Specific cross-sections have been observed to capture and tenaciously retain high levels of both liquids and finely divided solids within the channels of the fibers. The liquids are held through capillary forces, while the solids are mechanically entrapped within the channels and do not require adhesives to bond. Their retention is sufficient to allow these impregnated fibers to be used in high-flow applications without experiencing loss of the reagents. Exploiting this property, one can use this type of fiber to support a host of reagents in a practical format for various applications.