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Novel two-component gels of cetylpyridinium chloride and the bola-amphiphile 6-amino caproic acid: Phase evolution and mechanism of gel formation
Published in American Chemical Society
2012
Volume: 116
   
Issue: 9
Pages: 2722 - 2729
Abstract
A two-component gel resulting from the amphiphilic cationic surfactant cetylpyridinium chloride (CPC) in the presence of a structure-forming bola-amphiphilic additive 6-aminocaproic acid (6-ACA) was realized and investigated. At a critical 6 wt % of 1:1 CPC:6-ACA, the yellow colored gel resulted from a 3:1 v/v CHCl3:H2O critical binary solvent composition. The mixed amphiphilic system formed a 1:1 complex with a binding constant ∼0.83 × 104 M-1. Phase evolution and mechanism of gelation in the mixed CPC:6-ACA system was unraveled upon investigating the gel microstructure, based on spectroscopic, microscopic, and small-angle X-ray scattering (SAXS) investigations. The gel assembled as a lamellar organization, maintaining a loosely interdigitated bilayer structure of CPC and 6-ACA molecules through predominant charge transfer, H-bonding, and hydrophobic and intercomplex interactions. The SAXS pattern indicated a semicrystalline form to be the stable phase with alternating crystalline and amorphous layers; a novel mode of gelation with a widely disparate semicrystalline form of the lamellar gel was thus indicated, where the lamellar structure was deduced from the interplanar spacings. A transition from low viscosity reverse micellar solution to a yellow rigid gel upon aging was thus comprehended. The mixed amphiphile in varying polarity organic solvents in the presence of water indicated the nonconducive nature of gelation in very highly polar solvents, methanol, and DMF or, in very low polarity solvents, such as, cyclohexane and carbon tetrachloride. © 2012 American Chemical Society.
About the journal
JournalData powered by TypesetJournal of Physical Chemistry B
PublisherData powered by TypesetAmerican Chemical Society
ISSN15206106
Open AccessNo
Concepts (32)
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    Amphiphiles
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    Carbon tetrachloride
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    Cationic surfactants
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    Charge transfer
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    Coagulation
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    Gelation
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    Methanol
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    Organic solvents
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    Solvents
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    6-AMINOCAPROIC ACID
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    Amorphous layer
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    AMPHIPHILIC SYSTEMS
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    AMPHIPHILICS
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    BINARY SOLVENTS
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    Binding constant
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    CAPROIC ACID
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    Cetylpyridinium chloride
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    Gel formation
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    H-bonding
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    Highly polar solvent
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    INTERDIGITATED BILAYERS
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    Interplanar spacings
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    LAMELLAR ORGANIZATIONS
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    LOW VISCOSITY
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    PHASE EVOLUTIONS
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    Presence of water
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    REVERSE MICELLAR SOLUTION
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    Semicrystallines
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    Small angle x-ray scattering
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    STABLE PHASE
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    Two-component
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    Lamellar structures