Changes in mechanical behaviour of optical fibers aged in surfactant solutions

A solution containing surfactants presents appreciable changes in physical and chemical properties at the critical micelle concentration (CMC). Besides signal transmission for telecommunications, optical fibers are used in an increasing number of devices. Among different CMC determination techniques, optical fiber sensors have been increasingly used.However, reliability issues must be addressed for optical fiber sensors operating under particular conditions such as immersion in surfactants at CMC.The purpose of this work was to study the mechanical behavior of both silica coated and naked fibers in contact with two surfactants (sodium dodecyl sulphate (SDS) and Triton X-100) at the critical micelle concentration.Fatigue tests were implemented using a tensile test set-up. Optical fibers were wound onto pulleys and submitted to a tensile test using different velocities.Result analysis proves that immersion in SDS and Triton X-100 decreased the fiber strength especially near the CMC point.Beyond the CMC point, a fine surfactant molecule layer covered all the fiber surfaces and led to a small increase of fiber strength.

► Mechanical behavior of silica optical fibers aged in two surfactants is analyzed. ► Fiber strength measurement provides information about the critical micelle concentration. ► Aging in critical micelle concentration leads to a severe fiber strength decrease.