As mentioned in the experiment section, the obtained bulk viscosity was 3790 mPa•s at 80 ℃ and 9750 mPa•s at 25 ℃. The density of PDMS is reported to be 0.922 g cm -3 at 80 ℃ and 0.969 g cm -3 at 25 ℃ . From these values, the shift factor aT,η and the activation energy Eη of viscous flow at T0 = 80 + 273 [K] and T = 25 + 273 [K] was calculated to be aT,η = 2.9 and Eη = 17 kJ mol - 1 . That is, taking the time-temperature superposition principle , heating at 80 ℃ for 1 hour is equivalent to settling at room temperature (25 ℃) for 2.9 h in terms of bulk viscoelastic relaxation.