Temperature-induced three-phase equilibrium of medium-chain-length poly-3-hydroxyalkanoates-incorporated emulsion system for production of polymeric nanoparticle

The study investigated the effects of temperature on the phase behavior of medium-chain-length poly-3-hydroxyalkanoates (mcl-PHA)-incorporated emulsion system. It is suggested that the three-phase equilibrium consisting of lamellar liquid crystalline (L_a), bi-continuous microemulsion (D), and oil-swollen micelle phases formed in the vicinity of optimal formulation when the combination of phase inversion composition (PIC) and phase inversion temperature (PIT) methods was applied. The interaction effects between two parameters, viz. temperature and mcl-PHA molecular weight, influenced the lamellar/bi-continuous microemulsion formation within the mcl-PHA-incorporated emulsion. It is suggested that the lamellar/bi-continuous microemulsion phase of mcl-PHA-incorporated emulsion can be thermally induced from multiple emulsion system proximately before EIP, and its hypothetical formation mechanism is elucidated in this study.