Self-assembly in dilute mixtures of non-ionic and anionic surfactants and rhamnolipd biosurfactants

TY - JOUR

T1 - Self-assembly in dilute mixtures of non-ionic and anionic surfactants and rhamnolipd biosurfactants

AU - Liley, J R

AU - Penfold, J

AU - Thomas, R K

AU - Tucker, I M

AU - Petkov, J T

AU - Stevenson, P S

AU - Banat, I M

AU - Marchant, R

AU - Rudden, M

AU - Terry, A

AU - Grillo, I

N1 - Copyright © 2016 Elsevier Inc. All rights reserved.

PY - 2017/2/1

Y1 - 2017/2/1

N2 - The self-assembly of dilute aqueous solutions of a ternary surfactant mixture and rhamnolipid biosurfactant/surfactant mixtures has been studied by small angle neutron scattering. In the ternary surfactant mixture of octaethylene glycol monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene monododecyl sulfate, SLES, small globular interacting micelles are observed over the entire composition and concentration range studied. The modelling of the scattering data strongly supports the assumption that the micelle compositions are close to the solution compositions. In the 5-component rhamnolipid/surfactant mixture of the mono-rhamnose, R1, di-rhamnose, R2, rhamnolipids with C12E8/LAS/SLES, globular micelles are observed over much of the concentration and composition range studied. However, for solutions relatively rich in rhamnolipid and LAS, lamellar/micellar coexistence is observed. The transition from globular to more planar structures arises from a synergistic packing in the 5 component mixture. It is not observed in the individual components nor in the ternary C12E8/LAS/SLES mixture at these relatively low concentrations. The results provide an insight into how synergistic packing effects can occur in the solution self-assembly of complex multi-component surfactant mixtures, and give rise to an unexpected evolution in the phase behaviour.

AB - The self-assembly of dilute aqueous solutions of a ternary surfactant mixture and rhamnolipid biosurfactant/surfactant mixtures has been studied by small angle neutron scattering. In the ternary surfactant mixture of octaethylene glycol monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene monododecyl sulfate, SLES, small globular interacting micelles are observed over the entire composition and concentration range studied. The modelling of the scattering data strongly supports the assumption that the micelle compositions are close to the solution compositions. In the 5-component rhamnolipid/surfactant mixture of the mono-rhamnose, R1, di-rhamnose, R2, rhamnolipids with C12E8/LAS/SLES, globular micelles are observed over much of the concentration and composition range studied. However, for solutions relatively rich in rhamnolipid and LAS, lamellar/micellar coexistence is observed. The transition from globular to more planar structures arises from a synergistic packing in the 5 component mixture. It is not observed in the individual components nor in the ternary C12E8/LAS/SLES mixture at these relatively low concentrations. The results provide an insight into how synergistic packing effects can occur in the solution self-assembly of complex multi-component surfactant mixtures, and give rise to an unexpected evolution in the phase behaviour.

KW - Alkanesulfonates/chemistry

KW - Benzenesulfonates/chemistry

KW - Glycolipids/chemistry

KW - Micelles

KW - Neutron Diffraction

KW - Polyethylene Glycols/chemistry

KW - Rhamnose/chemistry

KW - Scattering, Small Angle

KW - Sodium Dodecyl Sulfate/analogs & derivatives

KW - Solutions

KW - Surface Tension

KW - Surface-Active Agents/chemistry

KW - Water/chemistry

U2 - 10.1016/j.jcis.2016.10.071

DO - 10.1016/j.jcis.2016.10.071

M3 - Article

C2 - 27816868

SN - 0021-9797

VL - 487

SP - 493

EP - 503

JO - JOURNAL OF COLLOID AND INTERFACE SCIENCE

JF - JOURNAL OF COLLOID AND INTERFACE SCIENCE

ER -