Self-assembly of Janus nanoparticles with a hydrophobic hemisphere in nanotubes.

We performed molecular simulations to investigate the morphologies and phase diagrams of self-assembled diblock Janus nanoparticles (JNPs) confined in nanotubes. A JNP is a unique anisotropic nanoparticle, which typically has more than two distinct surfaces, each with different properties. We derived qualitative phase diagrams of axial pressure versus the ratio of the diameter of the nanoparticle and the nanotube. Three distinct types of nanotube walls were considered: hydrophobic, hydrophilic, and hydroneutral. We observed diverse morphologies in JNP solutions, many of which have not been observed in bulk solutions. We also compared the self-assembled structures of diblock and triblock patchy particles. Under weak confinement, significant differences were observed between the different JNP designs. The orientation ordering and self-assembly behaviours of the JNPs can be qualitatively predicted based on the chemical nature of the nanotube wall and the JNP design.