Chapter 3 101 a hydrophobically modified cationic hydroxyethylcellulose, is also disclosed as being a preferable thickener for zinc-depositing compositions.73 It has been discovered that responsive particles with two contrasting polymers adsorbed to the particle core,74 can adsorb to the hydrophilic hair surface and render it hydrophobic, thereby conferring conditioning attributes to the hair. For example, grafting of aminopropyl-terminated dimethicone and polyethylenimine on titanium dioxide particles produces responsive particles. These particles form stable dispersions in water and aqueous solutions because they are sterically stabilized by expansion of the polyethylenimine into the aqueous medium. However, when they are deposited on hair and dried, the polyethylenimine layer collapses and the dimethicone layer expands to render the surface hydrophobic. The usefulness of these responsive particles is demonstrated by including them in typical conditioning shampoo and conditioner formulations. In the case of the shampoo, inclusion of the responsive particles results in a higher water contact angle on the treated hair and the conditioner with particles causes an increase in the hydrophobicity of the hair. On the other hand, shampoos containing ethoxylated alcohols have been found to enhance the deposition of large particle silicones (5–2000 microns) and in this case it is claimed that cationic polymer is not required.75 Two-phase Systems for Visual Attributes: There is esthetic appeal to products that exist as separate phases in the bottle but which mix during application to provide added benefit, such as moisturizing or conditioning, by interaction of the components of the two phases. The most obvious way to formulate such products is to use the immiscibility of water and oil in formulations that are shaken prior to use to produce a metastable emulsion. However, when a surfactant is included in the system such a visually attractive phase separation can be mixed into an emulsion due to shear in manufacturing and packing operations. There are known de-emulsifiers, which are widely used in the oil industry,