Silicone-Based Cholesteric Liquid Crystalline Polymers: Effect of Crosslinking Agent on Phase Transition Behavior

摘要

Silicone-based cholesteric liquid crystalline polymers (ChLCP) were fabricated with variable clearing temperatures as controlled by their chemical compositions. The chemical structures of the mesogenic monomers and ChLCP were confirmed by FTIR and H-1-NMR spectroscopy. The mesogenic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction measurements. The experimental results demonstrated that the glass transition temperatures and the clearing points of the liquid crystalline polymers decreased with increasing pro-portion of mesogenic crosslinking agent up to 12.50 mol % (LCP-3), and at higher proportion of crosslinking agent, the clearing points disappeared, indicating that the network chains have less chance to orient themselves. Thermogravimetric analysis showed that the LCP-3 was the most stable up to 230 degrees C.