The viscoelasticity of the rubber-ice interface determined by resonance shear measurement: influence of rubber T g.

We performed resonance shear measurements (RSM) using the low-temperature surface force apparatus (LT-SFA) to investigate how rubber composition influences the viscoelasticity of the rubber-ice interface. RSM data showed quite different behaviours depending on the styrene contents (5, 23 and 45 wt%) of poly(styrene-co-butadiene) rubbers. A mechanical model for RSM was applied to obtain the interface's viscous (b _s) and elastic (k _s) parameters across a temperature range of ca. -20°C to 0°C. All rubber-ice interfaces at a temperature of ca. -18° to -10°C showed a significant decrease in viscosity of 1 to 2 orders of magnitude in the maximum compared to the silica-ice interface, presenting properties of the ice premelted layer. This was attributed to the dominant viscoelastic contributions of the rubber with decreasing styrene content, and therefore to the decreasing glass transition temperature (T _g = -74, -55, and -31℃). The decrease in the viscosity was enhanced more for lower T _g rubbers. Between -10°C and -5°C, the rubber-ice viscosities converged at a value lower than silica-ice, which was indicative that the interfacial viscoelasticity in this regime was determined by increased contributions from the premelted layer of ice which was probably modulated by polymer-ice interactions. Finally, above -5°C all samples showed a rapid decay in viscosity and elasticity, suggesting that the premelted layer of ice is the main contributor. This study successfully demonstrated that rubber composition could have a profound impact on the viscoelasticity of the rubber-ice interface.