Patent ID: 8129466

Claim:
A nanoparticulate dispersion comprising: a) pigment particles having an average primary particle size of less than one micron; and b) a dispersant comprising a tri-block copolymer prepared by controlled radical polymerization and represented by the following formula, φ-(G) p -(W) q -(Y) s -T wherein φ is a hydrophobic residue of or derived from a monomeric initiator, and is free of a radically transferable group, G is a hydrophobic residue of an oxirane functional monomer reacted with a carboxylic acid, W is a residue of (meth)acrylic acid alkyl esters, and -(W) q - defines a W-block, Y is a residue of (meth)acrylic acid alkyl esters, and -(Y) s - defines a Y-block, wherein said W-block is different from said Y-block, T is or is derived from the radically transferable group of said monomeric initiator, and p, q, and s are each independently at least 1.