Nanocomposites based on Polyurethane/Poly(2-hydroxyethyl methacrylate) multicomponent polymer matrix and atrificial diamond nanofiller were created and the thermodynamic miscibility, dynamic mechanical, physico-mechanical properties and segmental motions have been investigated. The free energy of interaction values between the polymer components and nanofiller, calculated based on vapour sorption results, were negative and the thermodynamic affinity of PU network to the nanodiamonds is more powerful in compare with PHEMA. Dynamic mechanical analysis have demonstrated the essential changes in nanocomposites behaviour especially in the temperature range of PU glass transition. The creep rate spectroscopy have shown the suppression of segmental motion of PU and PHEMA in the nanocomposites, the maximal effect have been obtained for samples containing 0.25% of nanofiller. Introduction just of 0.25% of nanodiamond filler into the multicomponent polymer matrix resulted in the significant growth in stress at break and in Young's modulus.