The use of carbon nanotubes to sense matrix stresses around a single glass fiber

The stress field in a polymer matrix in the vicinity of a single glass fiber was mapped on the micron scale by using the strain-response of the Raman spectrum of single-wall carbon nanotubes (SWNTs) embedded in the matrix. A stress concentration zone is observed around the fiber end. Far away from the fiber, the applied stress value is recovered. The importance of this technique and the measurements for composite design and micro-mechanical models is discussed.