Silicone‐based cholesteric liquid crystalline polymers: Effect of crosslinking agent on phase transition behavior
Author(s) -
Jana Rabindranath N.,
Cho Jae Whan
Publication year - 2009
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.31021
Subject(s) - mesogen , differential scanning calorimetry , materials science , polymer , thermogravimetric analysis , glass transition , silicone , monomer , chemical engineering , fourier transform infrared spectroscopy , polymer chemistry , phase (matter) , phase transition , liquid crystal , composite material , organic chemistry , liquid crystalline , chemistry , thermodynamics , physics , optoelectronics , engineering
Abstract 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 1 H‐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 proportion 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°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009