Catanionic surfactants result from the pairing of oppositely charged amphiphilic molecules, forming a new class of surfactant molecules with various interesting lyotropic and thermotropic properties. With the aim of probing the role of both headgroup chemical nature/structure and molecular shape, a series of catanionic surfactants were synthesized. The cationic portion of the molecule is kept constant, being the dioctadecyldimethylammonium double chain. Different single-chained surfactants with varying headgroups and chain lengths are used as the anionic pair. The thermotropic behavior has been studied by DSC and the mesophase structural investigated by polarized light microscopy. The results indicate that, for a given chain length, parameters such as headgroup polarity and charge density, as well as volume, influence the catanionic surfactant behavior. The thermodynamic parameters are qualitatively evaluated, considering the headgroup chemical nature and the overall molecular structure.
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http://dx.doi.org/10.1016/j.jcis.2005.07.021 | DOI Listing |
Adv Colloid Interface Sci
December 2024
Department of Chemistry and Centre for Advance Study in Chemistry, Panjab University, Chandigarh, India. Electronic address:
Meeting the contemporary demand for the development of functional, biocompatible, and environment friendly self-assembled structures using efficient, cost-effective, and energy-saving methods, the field of colloids has witnessed a surge in interest. Research into cationic and anionic (catanionic) surfactant combinations has gained momentum due to their distinct advantages and synergistic properties in this context. Catanionic self-assemblies have emerged as promising contenders for addressing these requirements.
View Article and Find Full Text PDFEur Phys J E Soft Matter
September 2024
Institut de Chimie Séparative de Marcoule, BP 17171, 30207, Bagnols-sur-Cèze, France.
We describe the different mixed colloidal solutions that can be obtained when mixing equivalent quantities of a synthetic anionic clay to surfactants forming lamellar phases in the absence of added salt. The important quantity driving toward insertion or depletion is the osmotic pressure, of the lamellar phase and of the clay alone. Competition for water is the main driving force toward dispersion, inclusion or exclusion (phase separation).
View Article and Find Full Text PDFNanoscale
September 2024
Department of Chemical & Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, USA.
Vesicles are self-assembled nanocontainers (size ∼100 nm) in which solutes such as drugs can be encapsulated. There is great interest in triggering vesicle-micelle transitions (VMTs) because such transitions will result in the release of encapsulated solute. Here, we focus on (ROS) as a trigger for VMTs.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2024
Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Departamento de Engenharia Química, Universidade de Lisboa, 1049-001 Lisbon, Portugal. Electronic address:
Hypothesis: Aqueous solutions of mixtures of hydrogenated and perfluorinated ionic surfactants are known to display anomalous aggregation behavior due to the mutual phobicity between hydrogenated and perfluorinated chains. Despite all efforts, different experimental limitations prevented so far a definite interpretation of the existing experimental results: both intermicellar and intramicellar segregation remain acceptable possibilities.
Method: The potential for segregation of mixtures of fluorinated and hydrogenated ionic surfactants in water was assessed using atomistic molecular dynamics simulations.
Langmuir
September 2023
College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China.
Noncovalent interactions play a crucial role in driving the formation of diverse self-assembled structures in surfactant systems. Surfactants containing a benzene ring structure are an important subset of surfactants. These surfactants exhibit unique colloid and interfacial properties, which give rise to fascinating transformations in the aggregate structures.
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