Example of microprocessing in a natural polymeric fiber: Role of reeling stress in spider silk

Spider silk fibers were obtained by the monitored forced silking method. This procedure allows measurement of the silking force during the process and retrieving the fibers so their tensile behavior can be characterized. Silking conditions, including the reeling speed and the use of an anaesthetising gas, were varied to ascertain their influence on the tensile properties of the silk. In all cases, it was found that the tensile properties are determined by the silking stress, obtained by dividing the silking force by the diameter of the fiber. This suggests that the sophisticated spinning system of the spider can be characterized essentially by a single parameter, which controls the properties of spider silk almost independently of the reeling conditions.