RHEOLOGICAL PROPERTIES OF AQUEOUS-SOLUTIONS OF ALKYLDIMETHYLAMINE AND OLEYLDIMETHYLAMINE OXIDES - SPINNABILITY AND VISCOELASTICITY

Spinnability and viscoelasticity have been measured for aqueous solutions of alkyl- and oleyldimethylamine oxides (C(n)DAO, n = 14, 16, 18; ODAO) and sodium alginate. The aqueous solutions of C-16DAO at 35-degrees-C presented the spinnability of "ductile failure" and the polymer-like viscoelasticity. This aspect is consistent with the existence of isolated rodlike micelles in dilute solutions and their entanglement at high surfactant concentrations. Similar behavior was also observed for aqueous solutions of ODAO with 0-2 M NaCl and C-14DAO with 0.2 M NaCl and various amounts of HCl. The aqueous solutions of C-16DAO at 20-degrees-C and C18DAO at 25-degrees-C exhibited the spinnability of "cohesive fracture failure" and the gellike viscoelasticity. This behavior originates in the interacting platelike assemblies. The rheological properties of aqueous solution of sodium alginate transferred gradually from dilute polymer-type to gel-type. This corresponds to the formation of linkage structure by interpolymer interaction in concentrated solutions.