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Chen Y, Petkov JT, Ma K, Li P, R P Webster J, Penfold J, Thomas RK, Allgaier J, Dalgliesh R, Smith G. Manipulating the hydrophilic / hydrophobic balance in novel cationic surfactants by ethoxylation: The impact on adsorption and self-assembly. J Colloid Interface Sci 2024; 674:405-415. [PMID: 38941934 DOI: 10.1016/j.jcis.2024.06.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 06/20/2024] [Accepted: 06/23/2024] [Indexed: 06/30/2024]
Abstract
HYPOTHESIS Cationic surfactants have a wide range of applications, often associated with their affinity for a range of solid surfaces and their anti-microbial properties. Manipulating their adsorption and self-assembly properties is key to most applications, and this is commonly achieved through surfactant mixtures or manipulating their headgroup or alkyl chain structure. Achieving this through adjustments to their headgroup structure is less common in cationic surfactants than in anionic surfactants. Ethoxylation provides the ability to adjust the hydrophilic / hydrophobic balance, as extensively demonstrated in a range of anionic surfactants. EXPERIMENTS This same approach has been applied here to a range of ethoxylated cationic surfactants in the form of the quaternary ammonium salts, and their tertiary nonionic equivalents before quaternisation. Their adsorption and self-assembly properties are investigated using predominantly the neutron scattering techniques of neutron reflectivity, NR, and small angle neutron scattering, SANS. FINDINGS The trends in the adsorption at the air-water interface and the self-assembly in aqueous solution demonstrate how the hydrophilic / hydrophobic balance can be adjusted by varying the degree of ethoxylation and the alkyl chain length, and illustrate the degree of interdependence of the different structural changes. The variation in the adsorption and the micelle structure shows how the surfactant conformation / packing changes as the degree of ethoxylation and alkyl chain length increases and how the introduction of charge induces further changes.
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Affiliation(s)
- Y Chen
- ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK
| | - J T Petkov
- Arxada, Muenchensteinerstrasse 38, CH-4002 Basel, Switzerland
| | - K Ma
- ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK
| | - P Li
- ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK.
| | - J R P Webster
- ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK
| | - J Penfold
- ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK; Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OXON, UK.
| | - R K Thomas
- Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OXON, UK
| | - J Allgaier
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - R Dalgliesh
- ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK
| | - G Smith
- ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK
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Towesend VDJ, Creatto EJ, Pedroni LG, Pérez-Gramatges A. Synergism in binary surfactant mixtures containing a pH-responsive surfactant towards enhanced foam stability in brine at high pressure and high temperature conditions. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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