Micromechanical properties were obtained from instrumented microindentation hardness testing (MHI) performed with microindentation combi tester (MCT tester; CSM, Switzerland). The MHI experiments were carried out using a Vickers method: a diamond square pyramid (with an angle between non-adjacent faces 136 o ) was forced against the flat surface of a specimen. The instrument continuously recorded the loading force (F), penetration depth of the indenter tip to the specimen (h), and time (t). All measurements were made with the following parameters: maximum loading force 500 mN, dwell time (time of maximal load) 60 s, and linear loading and unloading rate 15000 mN/min (which corresponds to total loading and unloading time 2s). The smooth surfaces for MHI testing were prepared with a rotary microtome RM 2255 (Leica, Austria) using a freshly-prepared glass knife. For each sample, at least three independent cut surfaces were prepared and at least 10 indentations were carried out per surface (i.e. each sample was measured at least 30 times), and the final results were averaged. Five micromechanical properties were deduced from F-h or h-t curves according to ISO 14577-1 standard: indentation modulus (EIT), indentation hardness (HIT), Martens hardness (HM), indentation creep (CIT) and elastic part of indentation work (ηIT). Further details about microindentation measurements on polymer samples can be found in our recent publications .