Phase and Rheological Behavior of Surfactant/Novel Alkanolamide/Water Systems
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- 作者：Carlos Rodriguez ; Durga P. Acharya ; Koheita Hattori ; Takaya Sakai ; and Hironobu Kunieda
- 刊名：Langmuir
- 出版年：2003
- 出版时间：October 14, 2003
- 年：2003
- 卷：19
- 期：21
- 页码：8692 - 8696
- 全文大小：125K
- 年卷期：v.19,no.21(October 14, 2003)
- ISSN：1520-5827
文摘
Phase diagrams of water; sodium dodecyl sulfate (SDS); and a new foam booster, alkanoyl-N-methylethanolamide (C8, NMEA-8; C12, NMEA-12; C16, NMEA-16), were constructed at 25 
C. NMEA ishardly soluble in water: liquid-liquid phase separation occurs with NMEA-8, lamellar-phase formationoccurs with NMEA-12, and solid precipitation occurs with NMEA-16. In the presence of a small amountof NMEA, the surfactant hexagonal phase (H1) is extended to the dilute region. In the aqueous micellarsolution beyond the H1 phase, the viscosity dramatically increases and a viscoelastic solution is formedin NMEA-12 and NMEA-16 systems. The viscoelastic micellar solution formed in SDS-NMEA-12 systemsfollows the Maxwell model typical of wormlike micellar systems at low shear frequencies. In the SDS-NMEA-16 system, a gel-like highly viscoelastic solution is formed in the maximum-viscosity region.Rheological measurements show that the ability of NMEA to induce micellar growth increases in thefollowing order: NMEA-8 
NMEA-12 < NMEA-16. In agreement with this result, dynamic light scatteringmeasurements show that with an increasing mixing fraction of NMEA-12 or NMEA-16 in SDS-NMEAsystems the micellar size increases, leading to the formation of wormlike micelles.
C. NMEA ishardly soluble in water: liquid-liquid phase separation occurs with NMEA-8, lamellar-phase formationoccurs with NMEA-12, and solid precipitation occurs with NMEA-16. In the presence of a small amountof NMEA, the surfactant hexagonal phase (H1) is extended to the dilute region. In the aqueous micellarsolution beyond the H1 phase, the viscosity dramatically increases and a viscoelastic solution is formedin NMEA-12 and NMEA-16 systems. The viscoelastic micellar solution formed in SDS-NMEA-12 systemsfollows the Maxwell model typical of wormlike micellar systems at low shear frequencies. In the SDS-NMEA-16 system, a gel-like highly viscoelastic solution is formed in the maximum-viscosity region.Rheological measurements show that the ability of NMEA to induce micellar growth increases in thefollowing order: NMEA-8 NMEA-12 < NMEA-16. In agreement with this result, dynamic light scatteringmeasurements show that with an increasing mixing fraction of NMEA-12 or NMEA-16 in SDS-NMEAsystems the micellar size increases, leading to the formation of wormlike micelles.