Manipulating supramolecular gels with surfactants: Interfacial and non-interfacial mechanisms

Gel is a class of self-supporting soft materials with applications in many fields. Fast, controllable gelation, micro/ nano structure and suitable rheological properties are essential considerations for the design of gels for specific applications. Many methods can be used to control these parameters, among which the additive approach is convenient as it is a simple physical mixing process with significant advantages, such as avoidance of pH change and external energy fields (ultrasound, UV light and others). Although surfactants are widely used to control the formation of many materials, particularly nanomaterials, their effects on gelation are less known. This review summarizes the studies that utilized different surfactants to control the formation, structure, and properties of molecular and silk fibroin gels. The mechanisms of surfactants, which are interfacial and non-interfacial effects, are classified and discussed. Knowledge and technical gaps are identified, and perspectives for further research are outlined. This review is expected to inspire increasing research interest in using surfactants for designing/ fabricating gels with desirable formation kinetics, structure, properties and functionalities.

Automated summary

Gels are self-supporting soft materials widely used in various fields. The design of gels for specific applications requires fast, controllable gelation, desired micro/nano structure, and suitable rheological properties. Surfactants, although widely used in controlling material formation, are less understood in their effects on gelation. This review summarizes the studies on using different surfactants to control the formation, structure, and properties of molecular and silk fibroin gels. The mechanisms of surfactants, interfacial and non-interfacial effects, are classified and discussed. This review is expected to inspire further research on using surfactants for designing and fabricating gels with desired kinetics, structure, properties, and functionalities.