Figure 2: Dielectric properties of nanocomposites.
(a) Dielectric loss (ɛ″) reduced by the ratio of the β-process intensity over the corresponding matrix one, 
, as a function of frequency at T=380 K for neat P2VP (cross) and nanocomposites loaded with 5 (diamond), 10 (triangle), 16 (plus), 23 (circle) and 31 (square) vol%. The red dashed line is the contribution of the α- process to the global ɛ″ in the 31 vol% sample. The inset is the ratio of the α- and β-relaxation strength normalized by the corresponding quantity for the pure matrix 
as a function of the NP loading. The decreasing trend highlights the relative attenuation of the α-relaxation with the NP loading. (b) Similar measurements performed at T=410 K have been vertically shifted for clarity (see numbers on the right side). Solid lines are fits to the data with a σDC contribution at low frequency and a Havriliak–Negami function with a fixed α-relaxation shape (symmetric and asymmetric), as found in the neat matrix in order to illustrate its broadening when NP content is increased. σDC (black dashed line) stands for the contribution of the ionic conductivity. Inset: segmental relaxation time log(τα) as a function of 1,000/T. The solid line is fit to the neat P2VP data with the WLF equation.
