Study on Application of Novel Synthesized Silver Metallosurfactant …
299
Metallosurfactant can be synthesized by three types of reactions namely metathesis
reaction, ligand substitution, and ligand insertion reaction. In the metathesis reaction,
ion exchange occurs between cations and anions in the presence of a polar solvent.
Substitution of a less-labile ligand in place of more labile ligand occurs for ligand
substitution reaction, whereas the insertion of ligand without elimination takes place
in case of ligand insertion reaction. The primary mode of action of any surfactant
relies on the adsorption of its molecules at the boundary of a hydrophilic–hydrophobic
medium, which thereby reduces the interfacial surface tension and shows its effective
surface activity. On metal coordination, the molecular geometry of surfactant (ratio
of head group area to tail volume) and electrostatic charge distribution gets modified. Bridging of a central metal counterion with multiple surfactant head groups can
either promote attraction between the polar head groups and thereby bring them
closer, or push the head groups far apart through repulsive force, based on the
chemical structure of the metallosurfactant. Thus, the propensity of self-aggregation
and micellization is affected along with the substantial deviation in the aggregate
morphology. Metal incorporation helps to tune the characteristics of amphiphilic
surfactant through inducing new properties to the system as of the attributes (such
as acidic, basic, magnetic, and redox) of the attached metal (Brom et al. 2010). The
self-aggregation activity of a metallosurfactant can be controlled by tuning the type
of metal ion fused with a surfactant molecule. Other properties such as antibacterial, antimicrobial, catalytical, and magnetic properties can also be induced into the
surfactant system by the selection of an appropriate central metal. Therefore, the
property of the metallosurfactant is mostly characterized by the nature of the metal
incorporated in the surfactant molecule.
3 Recent Trends on Applications of Metallosurfactant
Conventional surfactants are mostly inadequate in the case of chemical reactivity.
Their properties are largely dependent on the hydrophobic/hydrophilic balance of the
nonpolar and polar moieties of its molecular structure. The introduction of transition
metal ions into amphiphilic structures is attracting significant attention as the variable
charge, catalytic activity, and magnetic properties of metal deliver a way of concentrating these potential features at interfaces (Kaur et al. 2016). Though such metallosurfactants are comparatively rare than conventional surfactants, these compounds
have recently found their application in diverse prospects such as homogeneous
catalysis, interfacial photophysics, magnetic resonance imaging, thin-film optoelectronics, templating of mesoporous materials, drug delivery, antimicrobial activities,
and anticancerous treatment (Griffiths et al. 2006). However, metallosurfactant has
not been much explored as a cleaning agent.
299
Metallosurfactant can be synthesized by three types of reactions namely metathesis
reaction, ligand substitution, and ligand insertion reaction. In the metathesis reaction,
ion exchange occurs between cations and anions in the presence of a polar solvent.
Substitution of a less-labile ligand in place of more labile ligand occurs for ligand
substitution reaction, whereas the insertion of ligand without elimination takes place
in case of ligand insertion reaction. The primary mode of action of any surfactant
relies on the adsorption of its molecules at the boundary of a hydrophilic–hydrophobic
medium, which thereby reduces the interfacial surface tension and shows its effective
surface activity. On metal coordination, the molecular geometry of surfactant (ratio
of head group area to tail volume) and electrostatic charge distribution gets modified. Bridging of a central metal counterion with multiple surfactant head groups can
either promote attraction between the polar head groups and thereby bring them
closer, or push the head groups far apart through repulsive force, based on the
chemical structure of the metallosurfactant. Thus, the propensity of self-aggregation
and micellization is affected along with the substantial deviation in the aggregate
morphology. Metal incorporation helps to tune the characteristics of amphiphilic
surfactant through inducing new properties to the system as of the attributes (such
as acidic, basic, magnetic, and redox) of the attached metal (Brom et al. 2010). The
self-aggregation activity of a metallosurfactant can be controlled by tuning the type
of metal ion fused with a surfactant molecule. Other properties such as antibacterial, antimicrobial, catalytical, and magnetic properties can also be induced into the
surfactant system by the selection of an appropriate central metal. Therefore, the
property of the metallosurfactant is mostly characterized by the nature of the metal
incorporated in the surfactant molecule.
3 Recent Trends on Applications of Metallosurfactant
Conventional surfactants are mostly inadequate in the case of chemical reactivity.
Their properties are largely dependent on the hydrophobic/hydrophilic balance of the
nonpolar and polar moieties of its molecular structure. The introduction of transition
metal ions into amphiphilic structures is attracting significant attention as the variable
charge, catalytic activity, and magnetic properties of metal deliver a way of concentrating these potential features at interfaces (Kaur et al. 2016). Though such metallosurfactants are comparatively rare than conventional surfactants, these compounds
have recently found their application in diverse prospects such as homogeneous
catalysis, interfacial photophysics, magnetic resonance imaging, thin-film optoelectronics, templating of mesoporous materials, drug delivery, antimicrobial activities,
and anticancerous treatment (Griffiths et al. 2006). However, metallosurfactant has
not been much explored as a cleaning agent.