Dynamics and extensional rheology of polymer–surfactant association complexes. Issue 25 (2nd June 2021)

• Record Type: Journal Article
• Authors: Martínez Narváez, Carina D. V.; Mazur, Thomas; Sharma, Vivek
• Is Part Of: Soft matter. Volume 17:Issue 25(2021)
• Page Start: 6116
• Page End: 6126
• Publication Date: 2021-06-02
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/d1sm00335f
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : We find the aqueous PEO–SDS mixtures show a significantly weaker concentration-dependent variation in the extensional relaxation time, filament lifespan, and extensional viscosity values than anticipated by the shear viscosity vs. concentration plots. Abstract : Understanding and characterizing the influence of polymers and surfactants on rheology, application, and processing is critical for designing complex fluid formulations for enhanced oil recovery, pharmaceuticals, cosmetics, foods, inks, agricultural sprays, and coatings. It is well-established that the addition of anionic surfactant like sodium dodecyl sulfate (SDS) to an aqueous solution of an oppositely-charged or uncharged polymer like poly(ethylene oxide) (PEO) can result in the formation of the polymer–surfactant association complexes (P 0 S − ACs) and a non-monotonic concentration-dependent variation in zero shear viscosity. However, the extensional rheology response of polymer–surfactant mixtures remains relatively poorly understood, partially due to characterization challenges that arise for low viscosity, low elasticity fluids, even though the response to strong extensional flows impacts drop formation and many processing operations. In this article, we use the recently developed dripping-onto-substrate (DoS) rheometry protocols to characterize the pinching dynamics and extensional rheology response of aqueous P 0 S − solutions formulated with PEO (P 0 ) and SDS (S − ), respectively. We find the PEO–SDS mixtures display a significantly weaker concentration-dependent variation in the extensional relaxation time, filament lifespan, and extensional viscosity values than anticipated by the measured shear viscosity.