| 초록 |
The surfactants are a rapidly growing area of scientific research and are industrially ubiquitous especially in both the chemical and consumer domains. They are used in detergents, cleaning agents, emulsifiers in food, pharmaceutical and cosmetic products. In many cases, the rheological properties of these systems are of interest in technological process. Aqueous solutions of certain ionic surfactants show the striking phenomenon of shear induced structure (SIS) which are responsible for drag reduction in turbulent flow.The formation of shear induced structure (SIS) of a micellar solution of cetylpyridinium chloride and sodium salicylate is studied by employing various techniques including a phase modulated flow birefringence, and mechnical rheomtry under shear in a cone-plate cell (rheo-optical method). We examine the shear viscosity, the shear modulus as a function of surfactants and additives concentrations.In the presence of NaSal, the micellar solution exhibits the viscoelastic properties due to theformation of worm like micelles. This solution normally exhibits shear induced structure formation and strong drag reduction properties. In the dilute concentration regime, rodlike micelles are formed, and the solutions behave as a real sol with a rather low viscosity. However, above the critical shear rate, we found structures oriented in the direction of flow, and the shearing prcess results the reversible formation of worm like micelles.
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