A fundamental study of the microencapsulation procedure utilizing coacervation in a polystyrene-cyclohexane solution.

Area of Science:

• Polymer science
• Materials science
• Chemical engineering

Background:

• Microencapsulation is a key process for controlled release applications.
• Polystyrene (PS) coacervation in cyclohexane is a viable method for microcapsule formation.
• Understanding phase separation dynamics is crucial for optimizing microencapsulation.

Purpose of the Study:

• To investigate the fundamental aspects of microencapsulation using temperature-induced coacervation.
• To analyze the role of PS polydispersity and temperature on phase separation.
• To evaluate the controlled release behavior of encapsulated anhydrous sodium sulphate (ASS) and the diffusion properties.

Main Methods:

• Temperature-induced coacervation of polystyrene (PS) in cyclohexane.
• Characterization of microcapsule structure (PS wall, talc shell).
• Controlled release studies using encapsulated ASS particles and the Higuchi model.

Main Results:

• PS polydispersity and temperature significantly affect coacervate and lean phase composition.
• Microcapsules exhibited a composite wall structure of PS and talc.
• The effective diffusion coefficient of ASS decreased from 10(-7) to 10(-8) cm/s with lower encapsulation temperatures.

Conclusions:

• Temperature-induced coacervation offers a tunable method for microencapsulation.
• Microcapsule wall composition and structure influence release kinetics.
• Optimizing encapsulation temperature is critical for controlling the diffusion rate of encapsulated substances.