TY - JOUR
T1 - Micelle-vesicle transition of oleyldimethylamine oxide in water
AU - Miyahara, Masahiko
AU - Kawasaki, Hideya
AU - Garamus, Vasil M.
AU - Nemoto, Norio
AU - Kakehashi, Rie
AU - Tanaka, Shimon
AU - Annaka, Masahiko
AU - Maeda, Hiroshi
N1 - Funding Information:
We thank Yousuke Ono for his help in the ELS measurements. This work was supported, in part, by the grant-in-aid for Scientific Research (no. 15750121) from The Ministry of Education, Culture, Sports, Science.
PY - 2004/11/15
Y1 - 2004/11/15
N2 - We studied the effects of the degree of ionization(α) and the surfactant concentration (C d) on the micelle-vesicle transition in salt-free oleyldimethylamine oxide (OlDMAO) aqueous solutions by the dynamic light scattering (DLS), the hydrogen ion titration, the small angle neutron scattering (SANS), the electrophoretic light scattering (ELS) and viscoelastic measurements. From the study of ionization effects, the micelle-vesicle transition was recognized as a change of aggregate size by the DLS measurement; however, the micelle-vesicle transition was not detected both in the ELS measurement and the hydrogen ion titration, suggesting that the electric properties of the worm-like micelles and the vesicles are very similar despite a large difference of shapes between them. From the results of the SANS, the DLS and the viscosity measurements, it was suggested that a concentration-dependent micelle-vesicle transition took place around C p = 10 mmol kg -1 for the solutions at α = 0.5. In the concentration-range 10 mmol kg -1 < C d < 150 mmol kg -1, the micelles and the vesicles coexisted. In the concentration region (C d = 10-50 mmol kg -1), the vesicle size increased with the surfactant concentration.
AB - We studied the effects of the degree of ionization(α) and the surfactant concentration (C d) on the micelle-vesicle transition in salt-free oleyldimethylamine oxide (OlDMAO) aqueous solutions by the dynamic light scattering (DLS), the hydrogen ion titration, the small angle neutron scattering (SANS), the electrophoretic light scattering (ELS) and viscoelastic measurements. From the study of ionization effects, the micelle-vesicle transition was recognized as a change of aggregate size by the DLS measurement; however, the micelle-vesicle transition was not detected both in the ELS measurement and the hydrogen ion titration, suggesting that the electric properties of the worm-like micelles and the vesicles are very similar despite a large difference of shapes between them. From the results of the SANS, the DLS and the viscosity measurements, it was suggested that a concentration-dependent micelle-vesicle transition took place around C p = 10 mmol kg -1 for the solutions at α = 0.5. In the concentration-range 10 mmol kg -1 < C d < 150 mmol kg -1, the micelles and the vesicles coexisted. In the concentration region (C d = 10-50 mmol kg -1), the vesicle size increased with the surfactant concentration.
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U2 - 10.1016/j.colsurfb.2004.04.011
DO - 10.1016/j.colsurfb.2004.04.011
M3 - Article
C2 - 15542314
AN - SCOPUS:8144223701
SN - 0927-7765
VL - 38
SP - 131
EP - 138
JO - Colloids and Surfaces B: Biointerfaces
JF - Colloids and Surfaces B: Biointerfaces
IS - 3-4 SPEC. ISS.
ER -