Phase behavior and thermal stabilization study of blue phase liquid crystal-unfunctionalized nanoparticle blends

We have studied the phase behavior of blue phase liquid crystal (BPLC)-unfunctionalized nanoparticle (NP) blends. Two different types of NPs which have different anchoring properties have been studied. Interestingly, Silica NP doped BPLC blends have revealed a small but clear positive shift of the Isotropic-BP phase transition temperature for lower concentration of NPs whereas with higher percentage of NPs we have observed a mixed phase consisted with chiral nematic (N*) and BP. On the other hand, low concentration polyhedral oligomeric silsesquioxanes (POSS) NPs which have stronger anchoring force than Silica NPs have enabled BP to stabilize thermally. Our experimental results agrees with the recent theory predicted that NP-defect interaction strongly depends on the interfacial energy between NP and LC which may be responsible for the observed effects in unfunctionalized NP-BPLC composite system.