Figure 4: Effect of NPs on relaxation times, rubbery plateau modulus and relative viscosity of polymers.
From: Phase stability and dynamics of entangled polymer–nanoparticle composites
Effect of NP content in SiO2–PEG/PMMA PNCs on (a), (b), (c) the three relaxation times (τo,τe,τt) for: SiO2–PEG2k/PMMA55k; SiO2–PEG2k/PMMA165k; and SiO2–PEG2k/PMMA280k respectively. The relaxation times are obtained from the G’ and G” crossover (Supplementary Fig. 8) at a fixed temperature difference from Tg. (d) Plateau modulus (Ge) obtained using Van Gurp analysis (Supplementary Fig. 9), as a function of particle concentration. (e) Relative viscosity ηr=ηPNC/ηneat, where η∼Geτt. The lines are predictions based on the modified Einstein (ME) expression 
(ref. 46), which accounts for a polymer brush of height; ME 1: Δ=2Rg (dashed line) or ME 2: Δ=fully stretched length (solid line). (f) Modified relative viscosity 
.
