Semicrystalline polymers may display a high degree of heterogeneity making it difficult to describe their mechanical behavior. Among other factors, the microstructure developed during process can lead to a gradient of properties. Thus, a multi-scale characterization of the mechanical response becomes necessary and instrumented indentation proves to be the most appropriate tool. An injected semi-crystalline polymer has been characterized and indentation allows to highlight the skin/core effect for the elastic properties arising for this process. Nonetheless, one of the main difficulties lies in the viscous nature of polymeric materials which can be probe by two complementary approaches: static nanoindentation (quite commonly used) and dynamic nanoindentation. The second part of this work is to characterize the viscoelastic properties of semi-crystalline polymers at different scales, building the master curve from both DMA and nanoDMA results taking into account the microstructure gradient. To that purpose, experiments were performed at temperatures between room temperature and 120°C varying the frequency over the range 0.3 – 100 Hz at both macro and micro scales. The construction of a master curve, using the Time Temperature Superposition principle, allows to determine the apparent activation energy linked to the relaxation process of this material.