Polymer matrix composites reinforced with carbonous fillers are of significant commercial importance thanks to their vast application base. As the performance of such composites largely depends on matrix-filler interaction, the present study is focused on the impact of surface chemical states of polymer matrix and carbonous filler on the viscoelastic performance of the composites. Here we report investigation of the filler-matrix interface through spectroscopic techniques such as X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Viscoelastic properties of various polymer matrix composites prepared by varying the filler volume fraction and/or the matrix/filler type have been studied through dynamic mechanical thermal analysis. Further, to understand the matrix-filler interaction, correlations between viscoelastic parameters and various structural parameters such as the surface area of filler and the surface chemical states of filler/matrix obtained through XPS have been studied. Strong correlations between the viscoelastic parameters and the matrix/filler surface chemical states have been observed, suggesting the XPS as an important tool to study the role of the surface functionalities present on the matrix/filler surface to define the matrix-filler interaction. The filler surface functionalities such as C bound O have been found more compatible with the polymers having aromatic ring in the repeat unit.The matrix-filler interaction in PMCs is affected significantly by the structure of polymer matrix and the surface characteristics such as area, roughness, and chemical state of filler. 14-17 Among these, the surface structure of fillers, affecting their dispersion, wettability and agglomeration tendency, governs the overall matrix-filler interaction largely. 14,[18][19][20][21][22][23] Presence of surface functional groups has been reported to modify the wettability of the filler, an important parameter determining the matrix-filler Additional Supporting Information may be found in the online version of this article. † Deceased on 08-08-2016.