Behavior of sodium dodecyl sulfate in acidic environment
Source abstract
Abstract
Abstract Whether sodium dodecyl sulfate (SDS) can be protonated in water under practically relevant acidities remains unclear because reported pK a values for its conjugate acid, dodecyl hydrogen sulfate (DHS), vary widely. As SDS is widely used as an electrostatic stabilizer in waterborne coating formulations, clarification of its acid stability is of practical importance. SDS protonation was therefore examined by turbidity measurements, acid titration, and 1 H NMR spectroscopy. Solutions containing 0.025–0.50 mol L −1 SDS remained fully transparent down to pH ≈ 0, with no turbidity or change upon heating to 45 °C. Titration with 1 M HCl showed a logarithmic pH decrease without buffer or equivalence points, indicating the absence of a measurable aqueous pK a . In 1 H NMR spectra (0.10 mol L −1 SDS), only ionic-strength-dependent shifts were observed, while integrals remained constant, confirming full solubility. Protonation, visible as line broadening and signal loss (~ 7%), occurred first at 1.26 mol L −1 DCl, where samples became heterogeneous. These results demonstrate that SDS remains fully deprotonated and stable under practical-relevant pH conditions, while conversion to the poorly soluble protonated form occurs only under extremely acidic, high-ionic-strength environments.
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Research context
OpenAlex topics: Surfactants and Colloidal Systems · Environmental Chemistry and Analysis · Electrostatics and Colloid Interactions
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References (18)
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1. Butler, LN, Fellows, CM, Gilbert, RG, “Effect of surfactant systems on the water sensitivity of latex films.” J. Appl. Polym. Sci., 92 1813–1823. https://doi.org/10.1002/app.20150 (2004)10.1002/app.20150 ↗
2. Arnold, C, Klein, G, Maaloum, M, Ernstsson, M, Larsson, A, Marie, P, Holl, Y, “Surfactant distribution in waterborne acrylic films. 2. Surface investigation.” Colloids Surf. A Physicochem. Eng. Asp., 374 58–63. https://doi.org/10.1016/j.colsurfa.2010.11.008 (2011)10.1016/j.colsurfa.2010.11.008 ↗
3. Zhang, K, Hu, H, Li, S, He, Y, Guo, J, “Effect of sodium dodecyl sulfate (SDS) on mechanical performance of polyvinyl-acetate-based emulsion polymer isocyanate.” Int. J. Adhes. Adhes., 98 102539. https://doi.org/10.1016/j.ijadhadh.2019.102539 (2020)10.1016/j.ijadhadh.2019.102539 ↗
4. Sigma-Aldrich, “Introduction to SDS-PAGE - Separation of Proteins Based on Size.” (accessed 19 August 2025), 2025.
5. Agmo Hernández, V, “An overview of surface forces and the DLVO theory.” ChemTexts, 9 10. https://doi.org/10.1007/s40828-023-00182-9 (2023)10.1007/s40828-023-00182-9 ↗
6. Guo, Y, Wang, C, Dun, J, Du, L, Hawley, M, Sun, CC, “Mechanism for the reduced dissolution of ritonavir tablets by sodium lauryl sulfate.” J. Pharm. Sci., 108 516–524. https://doi.org/10.1016/j.xphs.2018.10.047 (2019)10.1016/j.xphs.2018.10.047 ↗
7. “Advanced Chemistry Development Inc.” https://www.acdlabs.com (accessed 16 July 2025), n.d.
8. SciFinder Chemical Abstracts Service (CAS), “Record for SDS (CAS 151-21-3)/DHS (CAS 151-41-7).” https://scifinder-n.cas.org (accessed 11 November 2025), n.d.
9. Australian Industrial Chemicals Introduction Scheme (AICIS), Department of Health and Aged Care, “Lauryl (dodecyl) sulfates: Evaluation statement.” https://www.industrialchemicals.gov.au/sites/default/files/2022-12/EVA00116%20-%20Evaluation%20statement%20-%2022%20December%202022.pdf (accessed 16 July 2025), 2022.
10. Drugbank, “pka of sodium lauryl suflate.” https://go.drugbank.com/drugs/DB00815 (accessed 16 July 2025), n.d.
11. Chemicalbook, “pka of sodium lauryl sulfate.” https://www.chemicalbook.com/ChemicalProductProperty_EN_CB0723767.htm (accessed 16 July 2025), n.d.
12. Liu, B, Gao, M, Li, H, Liu, J, Yuan, S, Du, N, Hou, W, “Model of protocell compartments-dodecyl hydrogen sulfate vesicles.” Phys. Chem. Chem. Phys., 20 1332–1336. https://doi.org/10.1039/c7cp06379b (2018)10.1039/c7cp06379b ↗
13. Kanicky, JR, Shah, DO, “Effect of premicellar aggregation on the pKa of fatty acid soap solutions.” Langmuir, 19 2034–2038. https://doi.org/10.1021/la020672y (2003)10.1021/la020672y ↗
14. Wołowicz, A, Staszak, K, “Study of surface properties of aqueous solutions of sodium dodecyl sulfate in the presence of hydrochloric acid and heavy metal ions.” J. Mol. Liq., 299 112170. https://doi.org/10.1016/j.molliq.2019.112170 (2020)10.1016/j.molliq.2019.112170 ↗
15. Bayrak, Y, “Micelle formation in sodium dodecyl sulfate and dodecyltrimethylammonium bromide at different temperatures.” Turk. J. Chem., 27 487–492 (2003)
16. Covington, AK, Paabo, M, Robinson, RA, Bates, RG, "Use of the glass electrode in deuterium oxide and the relation between the standardized pD (paD) scale and the operational pH in heavy water." Anal. Chem., 40 (4) 196810.1021/ac60260a013 ↗
17. Glasoe, PK, Long, FA, “Use of glass electrodes to measure acidities in deuterium oxide1, 2.” J. Phys. Chem., 64 188–190. https://doi.org/10.1021/j100830a521 (1960)10.1021/j100830a521 ↗
18. Krezel, A, Bal, W, “A formula for correlating pKa values determined in D2O and H2O.” J. Inorg. Biochem., 98 161–166. https://doi.org/10.1016/j.jinorgbio.2003.10.001 (2004)10.1016/j.jinorgbio.2003.10.001 ↗