Abstract:

The advantages of polymer emulsifiers, such as good biocompatibility and flexible modification, have been recognized by researchers. Compared with small molecule surfactants, polymer emulsifiers can not only increase the viscosity of emulsion but also effectively reduce the surface tension of oil and water. Traditional polymer emulsifiers can form long-term stable emulsions, and have been widely used in food, cosmetics, pesticides, materials, petrochemical and other fields. However, in the fields of drug delivery, oil transportation and heterogeneous catalysis, long-term stable emulsions do not meet the needs of practical applications. Emulsions need to be controlled and on-demand demulsification under specific environments to achieve material release or oil-water separation to meet the requirements of applications. The stimulus-responsive polymer emulsifier can replace demulsifier in emulsion system to realize the transition from emulsion stability to rapid demulsification process under special circumstances. The reaction is controllable and sustainable, which can realize multiple response cycles, improve application efficiency and reduce the waste of resources. This paper reviews the research progress of stimulus-responsive polymer emulsifiers at home and abroad in recent years, and summarizes the action mechanism, response behavior and advantages and disadvantages of various stimulus-responsive polymer emulsifiers, such as pH, temperature, CO₂, light, redox, and multiple stimulus response. The application and development status of stimulus-responsive polymer emulsifiers in medicine, cosmetics, food, oil recovery, biocatalysis and other fields are summarized, and their future development prospects are also prospected.

Key words: stimulus response, polymer, emulsifier, application