Phase-dependence of gold nanoparticle dispersibility in blue phase and chiral nematic liquid crystals

Abstract

We investigate the dispersibility of spherical gold nanoparticles in three phases of a chiral liquid crystal – blue phase I, blue phase II and the cholesteric phase – by UV-visible spectroscopy and optical microscopy. UV-visible spectroscopy revealed that a gradual red-shift and broadening of local surface plasmon resonance occur in the blue I and cholesteric phases. Moreover, optical microscopy revealed a clear difference in the aggregation behavior of nanoparticles depending on the phase, with uniform textures being observed in the blue II phase, and agglomerates forming in blue I and cholesteric phases. The difference in the dispersibility of nanoparticles is discussed in terms of the structure of each liquid crystal phase.