Nuclear magnetic resonance and small-angle X-ray scattering studies of mixed sodium dodecyl sulfate and N,N-dimethyldodecylamine N-oxide aqueous systems performed at low temperatures

I22: SAXS/WAXS beamline at Diamond Light Source – an overview of 10 years operation

“…These are characteristic of living organisms and also many complex materials such as polymers and colloids. Relevant active research in the UK encompasses the fields of medicine (Ma et al, 2016;Burton et al, 2019;Coudrillier et al, 2016;Al-Jaibaji et al, 2018;Kudsiova et al, 2019), biology (Troilo et al, 2016;McGeehan et al, 2011;Arnold et al, 2011;Salamah et al, 2018), the environment (Neill et al, 2018;Seddon et al, 2016) and materials (Summerton et al, 2019;Wychowaniec et al, 2018;Burton et al, 2017), and includes studies of supramolecular organization in biomechanical systems (Xi et al, 2018;Kampourakis et al, 2018;Sui et al, 2014), corneal transparency (Morgan et al, 2018;Hayes et al, 2017), biological membranes (Barriga et al, 2016;Slatter et al, 2018;, polymer processing (Stasiak et al, 2015;Wan et al, 2018;Heeley et al, 2013;Toolan et al, 2017), colloids (Calabrese et al, 2019;Poulos et al, 2016;Mable et al, 2016), inorganic aggregates (Raine et al, 2018;Bennett et al, 2015;Zhou et al, 2018), liquid crystals (Hallett et al, 2014;Prehm et al, 2018;Lehmann et al, 2018) and devices (Xia et al, 2018;Barrows et al, 2016).…”

Pure and mixed aqueous micellar solutions of Sodium Dodecyl sulfate (SDS) and Dimethyldodecyl Amine Oxide (DDAO): Role of temperature and composition

“…They found both pure and mixed systems to form prolate ellipsoidal micelles, with larger axial ratios prevalent in the latter case. [31,34] Whilst most studies on the micellar phase of mixed surfactants have investigated the effects of chemical additives and molar ratios of the components (mainly the surfactant mixture), the effect of temperature, and especially cooling below room temperature, is yet to be investigated in detail, despite its practical importance (e.g. in low temperature detergency).…”

Understanding the Crystallization Process in Detergent Formulations in the Absence and Presence of Agitation

“…Crystallization was observed to begin around the stirrer bar rather than the air–liquid interface. From studies on similar surfactant systems, the crystals are likely to be composed of nonethoxylated alkyl sulfate hydrates since the system is below the Krafft temperature of these ionic surfactants. , Although these studies were done on quiescent samples, it is expected that the presence of mixing will not affect which component crystallizes first. These initial crystals are particularly important since their formation determines the time of product failure.…”

“…9−14 The tendency of an anionic surfactant system to crystallize is reduced upon addition of a nonionic surfactant, as has been reported for SDS + nonphenol polyethoxylate 9,12 and SDS + DDAO mixtures. 14,15 In the presence of a nonionic surfactant, the tendency for micelle formation increases, reducing the concentration of anionic surfactant monomers from which crystals form.…”

“…Despite the industrial significance of surfactant crystallization in detergent products, there are limited studies into the crystallization of mixed surfactant systems. − The tendency of an anionic surfactant system to crystallize is reduced upon addition of a nonionic surfactant, as has been reported for SDS + nonphenol polyethoxylate , and SDS + DDAO mixtures. , In the presence of a nonionic surfactant, the tendency for micelle formation increases, reducing the concentration of anionic surfactant monomers from which crystals form.…”