• Kjoniksen, Anna-Lena
• Knudsen, Kenneth D.
• Helgesen, Geir
• Galant, Celine
• Laukkanen, Antti
• Tenhu, Heikki
• Lund, Reidar
• Nyström, Bo

Abstract

Aq. mixts. of the anionic sodium dodecyl sulfate (SDS) surfactant and thermo-responsive poly(N-vinylcaprolactam) chains grafted with ω-methoxy poly(ethylene oxide) undecyl α-methacrylate (PVCL-g-C11EO42) have been characterized using turbidimetry and small-angle neutron scattering (SANS).Turbidity measurements show that the addn. of SDS to a dil. aq. copolymer soln. (1.0 wt%) induces an increase of the cloud point (CP) value and a decrease of the turbidity at high temps.In parallel, SANS results show a decrease of both the av. distance between chains and the global size of the objects in soln. at high temps. as the SDS concn. is increased.Combination of these findings reveals that the presence of SDS in the PVCL-g-C11EO42 solns. (1.0 wt%) promotes the formation of smaller aggregates and, consequently, leads to a more homogeneous distribution of the chains in soln. upon heating of the mixts.Moreover, the SANS data results show that the internal structure of the formed aggregates becomes more swollen as the SDS concn. increases.On the other hand, the addn. of moderate amts. of SDS (up to 4 mm) to a semidilute copolymer soln. (5.0 wt%) gives rise to a more pronounced aggregation as the temp. rises; turbidity and SANS studies reveal in this case a decrease of the CP value and an increase of the scattered intensity at low q.The overall picture that emerges from this study is that the degree of aggregation can be accurately tuned by varying parameters such as the temp., level of surfactant addn., and polymer concn. [on SciFinder(R)]

Topics

• impedance spectroscopy
• Sodium
• copolymer
• small-angle neutron scattering
• surfactant