Gels
Gel characterization and formulation development.
A gel can be considered as a solid three-dimensional network that spans the volume of a liquid medium. The network structure can result from either physical or chemical interactions, with varying degrees of stiffness.
Chemical gels include materials such as vulcanized rubbers and cured epoxy resins where the cross-links are covalent in nature. Physical gels are formed through intermolecular associations as a result of hydrogen bonding, Van der Waals forces or electrostatic interactions, and examples include particulate or colloidal gels, and associative polymers.
Malvern’s range of analytical instruments and application expertise can be used to
- Characterize rheological properties of the complete gelation or cure process
- Investigate gelation kinetics and mechanisms
- Control gelation through manipulation of electrostatic properties
- Monitor size and aggregation of liquid sols and micro-gel particles
Zeta potential can have a large impact on gelling behavior, with highly charged colloidal particles able to form colloidal gels, while weakly charged particles can adhere to form strong interconnected networks. Such behavior can also be significant in polymeric and surfactant gels where charge and solubility can affect the molecular conformation and degree of association.
The gelation or curing process, and the physical properties of the final gel system, can be fully characterized by rheological measurements. Particle size and aggregation behavior of sols and micro-gel particles can be determined through light scattering techniques.
