Temperature-tunable scattering strength based on the phase transition of liquid crystal infiltrated in well-defined macroporous random media

Temperature dependence of scattering strength for the visible light (488 nm) has been investigated for a siloxane-based macroporous monolith infiltrated with liquid crystal molecules. A macroporous gel with interconnected pores and organosiloxane skeletons is prepared via a sol–gel route by inducing the phase separation parallel to the hydrolysis and condensation of silicon alkoxide. The interconnected macropores of the dried gel are infiltrated with liquid crystal 4-cyano-4′-n-pentylbiphenyl (5CB) which undergoes the phase transition between nematic and isotropic at 35 °C. Temperature variation of the scattering strength for 5CB-filled gel is measured by means of coherent backscattering and total transmission, both of which exhibit a significant change in transport mean free path at around the phase transition temperature of 5CB. The results indicate that the scattering strength of 5CB-filled monolith gel can be tuned externally via temperature.