Shampoo and Conditioner Science 98 The living free radical polymerization techniques that have emerged in the last decade offer the prospect of preparing precise polymers with unprecedented accuracy in molecular structure and variety of chemical types.60 This technique has enabled synthesis of a wide diversity of block and graft polymers that were previously unattainable. Such polymers offer the prospect of conferring conflicting properties within one molecule, which in turn can lead to improved compatibilities in the same system while maintaining stability. These conflicting properties could possibly be achieved by blending different polymers, but different polymers do not mix readily at the molecular level and phase separation may result.61 Block, graft, and gradient copolymers serve to compatibilize such compositions and gradient polymers have been proposed for this purpose. Block copolymers comprising polycationic blocks and nonionic blocks for surface deposition62 and for improved foam retention63 have been claimed which are desired to deposit on hair in order to modify the chemical properties of the surface for protection or compatibility to modify hair’s hydrophobic or hydrophilic surface properties or to modify feel or mechanical properties of the substrate from two-in-one products. The polymers disclosed are block copolymers of polyTMAEAMS (methylsulfate [2-(acryloyloxy) ethyl]-trimethylammonium) g/mole) and polyacrylamide. Conditioning shampoos can also be formulated to function by mechanisms other than cationic polymer-induced complex coacervation, such as: • Conditioning can be achieved, for example, by including chain extended silicones in an anionic surfactant-based shampoo. Specific examples of useful silicones include silicone emulsions containing divinyldimethicone/dimethicone copolymer.64 • Shampoos containing polyalkylene oxide alkyl ether particles give larger coacervate cohesive flocs (20–500 microns) that resist shear and confer superior deposition efficiency on hair for good wet conditioning.65