The invention relates to oligo(ethylene glycol) methacrylate microgels, a method for prepn. of same and uses thereof in various fields of application, such as optics, electronics, pharmacy and cosmetics. Said microgels have the advantage of being monodisperse, pH-sensitive and thermosensitive. The microgels can carry magnetic nanoparticles or biol. active mols. Said microgels can also form transparent films, which have original optical and electromagnetic properties. The microgels are manufd. by polymn. of 50-90 mol% diethylene glycol Me ether methacrylate, 10-50 mol% oligo(ethylene glycol) Me ether methacrylate (d.p. 3-12), and 0.1-20 mol% CR1R2:CR3R4 [R1-4 = H, halo, or hydrocarbyl, with ≥1 of the groups having ≥1 CO2H or CO2M (M = cation)] group, and a crosslinking monomer.