Tuning the thermodynamic behavior and phase separating morphology of dynamically asymmetric LCST blends through the self-assembly of hydrophilic spherical nanoparticles

In this study we investigated the effect of hydrophobic R974 Aerosil spherical nanoparticles as a potential i- to control kinetics of phase separation by slowing down or arresting the domain growth ii- to induce preferred phase separating morphology by tuning the dynamic asymmetry. Nanoparticles considerably slowed down phase separation for different mechanisms (NG, SD, and VPS) at a low volume fraction of 0.5% which was intensified as the volume fraction was increased. Remarkably, at 2 vol% of R974 nanoparticles the dynamic asymmetry increased considerably and thermodynamically controlled phase separation mechanisms (NG and SD) changed to VPS mechanism. At 2 vol% nanoparticle phase separation was arrested and a stable percolating network structure induced by VPS and a stable co-continuous structure induced by SD were formed in presence of R974 nanoparticles. TEM images indicated that double percolated structures were induced in presence of 2 vol% of the R974 nanoparticle through the PS-rich one