Modern Chemistry & Applications

The aqueous phase behavior of linear alkylbenzene sulfonate/polycarboxylate polymer systems

9^th Global Chemistry Congress

July 23-24, 2018 | Lisbon, Portugal

M Hussain, M Nagaraj, O J Cayre, H Tantawy, E S J Robles and A E Bayly

University of Leeds, UK
Procter & Gamble Ltd., UK

Posters & Accepted Abstracts: Mod Chem Appl

Abstract:

Linear alkylbenzene sulfonate (NaLAS) surfactant, used in detergent products, is often combined with polycarboxylate polymers that act as anti-redisposition agents and viscosity modifiers. This work investigates the interaction of the polymer and surfactant in an aqueous system via a NaLAS-polyacrylate-water phase diagram at 50??�C. It shows the multiple effects of the depletion flocculation phenomena depending upon the region of the phase diagram being considered. 2H-NMR shows that the sizes of the multilamellar vesicle structures increase with polymer concentration. This is the first time that 2H-NMR has been used to probe the diffusion and anisotropy of D2O within the bilayers of the vesicles for such a system. The phase diagram, shown below, presents a micellar region at surfactant concentrations of up to 35 wt% NaLAS and a lamellar phase plus micellar region at higher concentrations, consistent with previous observations by Stewart and Richards. As polymer is added at low surfactant concentrations, between 10 and 20 wt% NaLAS, a non-birefringent phase is observed; perhaps a polymer rich phase resulting from depletion flocculation. At high surfactant concentrations, a second lamellar phase is also induced, different in bulk density from the original, again likely resulting from depletion flocculation of multilamellar vesicles. 2H-NMR was used to determine an increase in average multilamellar vesicle size as a function of polymer concentration. The mechanism causing this is likely a result of vesicle fusion resulting from depletion flocculation caused by polymer addition, as initially described by Van de Pas.

Biography :

E-mail: ed10m5h@leeds.ac.uk