Raman probing of adhesion loss in carbon nanotube – reinforced composite

Raman spectroscopy of a carbon nanotube – reinforced phenolic resin is used to study the interaction of nanotubes with a host matrix. The observed sublinear dependence of the Raman G-band shift on the matrix strain, accompanied by inhomogeneous broadening of the spectral line, is interpreted as a gradual loss of adhesion between nanotubes and the polymer. An approach to simulate the ensemble-averaged Raman response of the nanotubes in composite is proposed, that takes into account nanotube orientation, angular dependence of the polarized Raman response of nanotubes, and adhesion loss between the nanotubes and the polymer. The comparison of the observed Raman line shapes and Raman shifts with simulation provides interesting insights into the micromechanics of nanotube interaction with polymer.