Interfacial and Micellization Behavior of Cetyltrimethylammonium Bromide (CTAB) in Water and Methanol-Water Mixture at 298.15 to 323.15 K

Shah

Asia-Pacific J Chem Eng

et al. 2021

Methanol–water system possesses unusual interactions, which may affect surfactant self‐assembly. The main objective of this study was to investigate the interactions and aggregation behavior of ionic surfactants sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) and their equimolar catanionic binary mixtures (CAM) and their ternary mixtures with poly(ethylene oxide) (PEO) in aqueous solutions containing different volume percentages of methanol. Conductometry, surface tensiometry, and dynamic light scattering were employed for this purpose. The aggregation in all the systems showed methanol‐dependent patterns. The maximum shifts observed in the critical aggregation concentrations were 5.5, 2.7, 6.3, 4.1, and 4.4 mM, respectively, for SDS, CTAB, CAM, SDS/PEO, and CTAB/PEO systems for variation in MeOH from 5% to 30% v/v. The change in dielectric of the media and chaotropic nature of methanol was responsible for alteration in self‐assembly. The nature of surfactant especially and head group hydrophobicity also played a significant role in the process. The maximum change in area per molecule (i.e., ~4 nm2) occurred for CTAB/PEO system. The aggregation was delayed in surfactant solutions; however, the presence of polymer induced aggregation due to favorable polymer–surfactant interactions involving the surfactant adsorption onto polymer chains and formation of mixed aggregates. The hydrodynamic radii for CTAB/PEO systems, which were nearly 10 times greater than those recorded for SDS/PEO, showed the transition of system to nonspherical aggregated states. In short, the presence of methanol retarded the aggregation in surfactant and surfactant–polymer systems.

Section: Resultsmentioning

confidence: 50%

“…In the premicellar region, the steepness in rise of conductivity shows a direct dependence on methanol content 33 . It is worthwhile to note that only the very initial concentration region represents the non‐aggregated surfactant and the investigated concentration range mostly represents the self‐assembled state of CTAB.…”

Section: Resultsmentioning

confidence: 97%

Effect of methanol on surfactants and surfactant–PEO mixtures

Shah

Asia-Pacific J Chem Eng

et al. 2021

ACS Appl. Energy Mater.

“…27 The aqueous solution of CTAB at CMC has a surface tension within this range. 28 Thus, the surfactant (CTAB) helps in exfoliation of graphite layers by reducing the surface tension of water. Further, it electrostatically stabilizes the exfoliated graphene flakes by getting adsorbed on the surface.…”

Section: Resultsmentioning

confidence: 99%

“…Liquids with surface tensions between 30 and 40 mJ m –2 are known to be an ideal medium for LPE of graphite . The aqueous solution of CTAB at CMC has a surface tension within this range . Thus, the surfactant (CTAB) helps in exfoliation of graphite layers by reducing the surface tension of water.…”

Section: Resultsmentioning

confidence: 99%

Graphene-Supported Palladium Nanostructures as Highly Active Catalysts for Formic Acid Oxidation Reaction

Pramanick

Kumar

Chowdhury

et al. 2022

Palladium (Pd) has recently emerged as a stable and active yet cheaper alternative electrocatalyst to costly platinum for the formic acid oxidation reaction (FAOR). Crystal engineering, wherein particle morphologies, defects, and facets are selectively altered, can enhance the electrocatalytic activities of Pd nanostructures. Herein, we have demonstrated that a combination of crystal engineering and supporting the nanostructures on a conductive catalyst support (few-layered graphene (FLG)) leads to highly enhanced catalytic activities. FLG was prepared by using liquid-phase exfoliation in aqueous solution of a surfactant. Swollen liquid crystals promoted the nanostructuring of Pd as well as nanocomposite formation as they acted as “soft” templates. Spherical nanoparticles (Pd0D), nanowires (Pd1D), and nanosheets (Pd2D) of Pd were formed and preferentially deposited on graphene sheets on the exposure of mesophases containing graphene along with Pd2(dba)3 to hydrazine vapor, H2, and CO, respectively. The Pd1D/FLG nanocomposite exhibited an exceptional electrocatalytic activity for FAOR. It had many folds higher electrocatalytically active surface area (ECSA), current density, and stability than the other nanocomposites as well as other Pd-based catalysts reported in the literature. Increased presence of more active Pd(100) facets was identified as the major reason for the enhanced catalytic activity of Pd1D. Supporting the Pd nanostructures on graphene led to enhanced electrocatalytic activities owing to the preserved surface sites of Pd nanoparticles, enhancement in electronic conductivities, and mass transfer and charge transfer from graphene to Pd.

“…Cationic CNSL-based surfactants Three commercial surfactants (Benzyldimethylhexadecylammonium Chloride [146], Cetyltrimethylammonium Bromide [147][148][149] and Cetylpyridinium Chloride [148,149]) were added in this figure (see Figure 11) for comparison purposes.…”

mentioning

confidence: 99%

CNSL, a Promising Building Blocks for Sustainable Molecular Design of Surfactants: A Critical Review

Roy¹,

Fajardie

Lepoittevin

et al. 2022

Molecules

Surfactants are crystallizing a certain focus for consumer interest, and their market is still expected to grow by 4 to 5% each year. Most of the time these surfactants are of petroleum origin and are not often biodegradable. Cashew Nut Shell Liquid (CNSL) is a promising non-edible renewable resource, directly extracted from the shell of the cashew nut. The interesting structure of CNSL and its components (cardanol, anacardic acid and cardol) lead to the synthesis of biobased surfactants. Indeed, non-ionic, anionic, cationic and zwitterionic surfactants based on CNSL have been reported in the literature. Even now, CNSL is absent or barely mentioned in specialized review or chapters talking about synthetic biobased surfactants. Thus, this review focuses on CNSL as a building block for the synthesis of surfactants. In the first part, it describes and criticizes the synthesis of molecules and in the second part, it compares the efficiency and the properties (CMC, surface tension, kraft temperature, biodegradability) of the obtained products with each other and with commercial ones.