The glass fiber–polymer matrix interface/interphase characterized by nanoscale imaging techniques

Atomic force microscopy (surface topography, phase imaging, lateral forces), atomic force acoustic microscopy, and dynamic mechanical analysis (modulus mapping) were used to characterize the interphase region of unsized, industrially sized, and plasma coated glass fibers (GF) in GF/polyester composite. The nanoscale imaging techniques revealed the sharp changes in mechanical properties within 0.1 μm of the interlayer/fiber and matrix/interlayer interfaces for plasma polymer coated fibers, or at the matrix/fiber interface in the case of unsized fibers. A region of modified matrix with a thickness of 0.5 μm was determined near the fiber surface in the case of industrially sized fibers.