Patent ID: 8569421

Claim:
A polymer composition comprising mikto star macromolecules, wherein each mikto star macromolecule comprises: a core and a plurality of ATRP arms, said plurality of ATRP arms comprising: a) at least one arm of the plurality of ATRP arms is a hydrophilic homopolymeric ATRP arm, wherein the homopolymeric ATRP arms of the polymer composition have a polydispersity index of between 1.0 and 2.5; and b) at least one arm of the plurality of ATRP arms is a copolymer ATRP arm, wherein the copolymer ATRP arms of the polymer composition have a polydispersity index of between 1.0 and 2.5, and said copolymer ATRP arm comprises: 1) a longer hydrophilic segment proximal to the core; and 2) a shorter hydrophobic segment distal to the core; wherein: i) the homopolymeric ATRP arms are shorter than the copolymer ATRP arms; and ii) the polymer composition behaves as a thickening agent in an aqueous medium at concentration of less than 5 wt. %.