Transition of phase-separated PBTPA/PMMA solution droplets from core–shell to Janus morphology under UV light irradiation

Here, we report the morphological transition of a phase-separated structure from core–shell to Janus morphology in droplets consisting of a poly(4-butyltriphenylamine) (PBTPA)/poly(methyl methacrylate) (PMMA) blend solution, induced by UV light irradiation. We obtained a phase-separated structure formed by the evaporation of the solvent from polymer solution droplets dispersed in an aqueous solution containing a surfactant. The rate of transition decreased with increasing polymer concentration and diameter of the droplet. It was also found that the transition was caused by UV light with a wavelength of 365 nm, which is mainly absorbed by PBTPA, indicating that this phenomenon is triggered by PBTPA. When the droplet was heated to 75 °C, no transition was observed. UV light irradiation causes the unexpected structural transition from core–shell to Janus in droplets consisting of a poly(4-butyltriphenylamine) (PBTPA)/poly(methyl methacrylate) (PMMA) blend solution. We obtained a phase-separated structure formed by the evaporation of the solvent from polymer solution droplets dispersed in an aqueous solution containing a surfactant. It was also found that the transition was caused by UV light with a wavelength of 365 nm, which is mainly absorbed by PBTPA, indicating that this phenomenon is triggered by PBTPA.