Interactions between interfaces dictate stimuli-responsive emulsion behaviour

Area of Science:

• Colloid and Interface Science
• Materials Science
• Chemical Engineering

Background:

• Stimuli-responsive emulsions combine long-term storage with controlled release.
• External triggers like pH and temperature changes activate release.
• Understanding the factors governing their stability and responsiveness is crucial.

Purpose of the Study:

• To investigate the role of microgel particle properties in thermo-responsive emulsion behavior.
• To determine how microgel morphology at liquid interfaces influences emulsion stability and responsiveness.
• To elucidate the interfacial interactions governing stimuli-responsive emulsion performance.

Main Methods:

• Characterization of microgel particles (polymeric vs. colloidal nature).
• Analysis of microgel morphology at liquid interfaces.
• Investigation of interfacial interactions and their impact on emulsion stability and thermo-responsiveness.

Main Results:

• Thermo-responsive emulsion behavior is governed by inter-facial interactions, not intra-particle interactions.
• Colloidal properties of microgels ensure Pickering emulsion stability, while polymeric properties enable stimuli-responsiveness.
• Microgel morphology at the interface and shared microgels in flocculated systems are critical for responsiveness.

Conclusions:

• Microgel particle properties, specifically their polymeric or colloidal nature and interfacial morphology, are paramount for stimuli-responsive emulsions.
• Interfacial forces exerted by microgels play a pivotal role in designing and controlling responsive emulsion systems.
• Optimizing microgel design and interfacial behavior is key to achieving desired controlled release functionalities.