J. Cosmet. Sci., 62, 251–258 (March/April 2011) 251 Polymer/surfactant interactions and nanostructures: Current development for cleansing, release, and deposition of actives P. SOMASUNDARAN and P. PUROHIT, Center for Particulate and Surfactant Systems and Langmuir Center for Colloids and Interfaces, Columbia University, New York, NY 10027. Synopsis Nature exhibits a variety of remarkable phenomena that are useful but diffi cult to be imitated in real life. Examples are a “touch me not” plant folding up upon being attacked or microbes depositing on ocean vessels even under hostile conditions. Understanding of mechanisms governing these phenomena can prove powerful for developing new classes of cosmetic products. Systems based on polymer/surfactant colloid chemistry are being developed for achieving transport and release of cosmetic and pharmaceutical molecules at desired rates and desired sites. Modifi cations of the surfactants and polymers provide cleansing properties such as scaveng- ing of odor and sebaceous body excretions and controlled delivery and deposition of sensory/hygienic attrib- utes. New surfactants (sugar based and bio surfactants), hybrid polymers (silicone based and hydrophobically modifi ed) and nanogels have been recently synthesized which may have applications in fi elds of cosmetics/ fragrances/drugs etc. Due to the associative nature of the hydrophobic groups, hybrid polymers can form intramolecular nanodomains at all concentrations of the polymer and inter-molecular aggregates at high concentrations. New hybrid polymers and nano-gel particles can be developed with ability to extract and deliver actives by varying such properties as swelling/shrinking capacity and sensitivity to temperature, shear and dilution. Control of such properties as size, shape and cross linking of nanohybrid particles offer maxi- mum opportunity for producing families of nanovehicles in personal and homecare industry. This review ar- ticle provides an insight into current developments in fi eld of nano-surfactant science, comprising discussions on nanogel particles, hybrid polymer and liposomes. INTRODUCTION Nano-sized systems are currently fi nding increasing applications in personal care (1-4) and pharmaceutics (5,6). Potential advantages of these nano systems include homoge- neous distribution in the formulation, better encapsulation and the ability to release en- capsulates at targets in a controlled fashion. The delivering agents as nanogel particles/ emulsions, hybrid polymers, and liposomes are discussed in this paper. Innumerable ac- tive nanostructures exist in nature in different forms, exhibiting a variety of sensory phenomena. A most intriguing example is that of the nodes of plant ‘Mimosa pudica’ that is responsive to the stimulus of touch (7). When the plant is touched, the liquid in the nano and microgels in the nodes apparently get squeezed out leading to the folding of the leaves and dropping of the braches. This principle can conceivably be used in designing