PA09 Injection of 5CB into porous silica microcapsules under reduced pressure

Abstract

Porous silica microcapsules have been studied on a variety of functionalization such as DDS. Confined nematic liquid crystal has been intensively studied to reveal that much modification of phase transitions is caused due to the enhancement of interaction with surfaces of pores. In this work, the injection of nematic liquid crystal under reduced pressure was studied to clarify the condition in which the pore and inner space of the capsules are filled with the liquid crystalline molecules. In this work, some techniques were examined to inject a room-temperature nematic liquid crystal, 5CB, into the inner space of microcapsule under reduced pressure. Under 10^<-1> mmHg of the pressure, the injection was attained up to about 50% of the inner space of microcapsules of which averaged diameter is 10μm with the averaged pore size of 10 nm. The phase transitions were studied by DSC to reveal the two crystalline states are formed while the clearing point is not affected. This indicates that a macroscopic bulk nature of 5CB still exists and some portions of 5CB which are probably contacting the surface of silica is affected on its morphology probably due to the surface energy which will make change of nucleation of crystal.