Figure 3: Rheological behaviour of the nanocomposites.

(a) Master curves of storage (G′, symbols) and loss (G″, solid lines) moduli as a function of frequency at T_ref=473 K for neat P2VP 554 kg mol⁻¹ (cross) and nanocomposites loaded with 5 (diamond), 10 (triangle), 16 (plus), 23 (circle) and 31 (square) vol% in silica. The master curves were obtained by frequency-scale shifts only. Inset: relative increase of the storage modulus as a function of the silica volume fraction for ω where tan(δ)=G″/G′ reaches its minimum (Supplementary Fig. 10). The solid line is a fit to the Doolittle equation⁴¹ with A=0.052 and B=19.46 (see text). (b,c) Respective measurements performed in different matrices at a single temperature T=453 K for (b) M_w=219 kg mol⁻¹ and (c) M_w=36 kg mol⁻¹. The legends are the same as that in a, where the symbols and solid lines respectively stand for G′ and G″.