Chapter 3 99 • A conditioning shampoo containing a polyester formed from adipic acid and pentaerythritol provides conditioning for dry hair (possibly from reduced hair friction), with no greasy feel.66 • Inclusion of polybutene is thought to increase the deposition of silicone conditioners and provide improved conditioning benefits, such as wet and dry feel and combing. O’ Lenick disclosed a unique class of alkyl polyglucoside quaternary surfactants possessing all of the multifunctional attributes of cleansing, conditioning and self-preserving.67 This could have the potential of greatly simplifying the formulation of multifunctional shampoos. A conditioning shampoo that contains a conditioning gel phase in the form of vesicles is described by Unilever researchers.68 Cationic conditioners are usually incompatible with anionic shampoos, and consequently conditioners based upon cationic surfactants are usually applied as separate post-shampoo products. The Unilever researchers prepared a conditioning gel phase by combining a small amount of water, fatty alcohol, a long-chain secondary anionic surfactant (sodium cetostearyl sulfate), and a long-chain cationic surfactant (behenyltrimethylammonium chloride), and subjecting the mixture to high shear to form a stable vesicular gel phase. Prolonged shear causes the lamellar gel phase to roll-up into an array of multilamellar vesicles (Figure 17). The gel phase was added to a dilute primary surfactant solution (sodium laureth sulfate) to form a conditioning shampoo with that conferred good wet smoothness on hair. Figure 17. Lamellar gel subjected to high shear rolls up into vesicles of gel phase that can be used for conditioning. (Figure reproduced from US Patent Application 20110243870).