Double hydrophilic diblock copolymers (DBCs) contained chemically complementary methoxypoly(ethylene oxide) and poly(acrylic acid) (MOPEO-b-PAAc) with the constant length of MOPEO block (M vMOPEO ¼ 5 kDa) and variable length of polyacid block (M nPAAc ¼ 9.9 Ä 23.1 kDa) were synthesized by a free radical block copolymerization of PAAc with methoxypoly(ethylene glycol) (MOPEG). These copolymers were pH-sensitive in aqueous medium, namely, at low pH the polyacid blocks were protonated and formed the intramolecular polycomplexes with MOPEO blocks that resulted in an intense micellization initiated by hydrophobic interactions between non-polar bound segments of the blocks. Hydrophobic ''core'' of the micelles comprised H-bonded segments of MOPEO and PAAc blocks while hydrophilic ''corona'' included the surplus units of longer blocks. The capability of DBCs as templates for the silver nanocluster/nanoparticle is considered. The kinetics of the Ag-nanoparticle growth in the copolymer matrices and optical properties of nanoclusters and nanoparticles were determined and discussed.