Synthesis and properties of cholesteric liquid crystalline elastomers

Phase transition behavior of silicone based liquid crystalline polymers

“…shows the FT-IR spectra of the crosslinking agent (M-1), mesogenic monomer (M-2) and one LC polymer (e.g., L-1 at the initial stage (0 h) and after 12 h of reaction). This shows that M-1 has the characteristic peaks corresponding to C-H stretching of vinyl at 3032 cm -1 , C-H of methylene at 2921 and 2848 cm -1 , alkane ester group (-RCOOR-) at 1710 cm -1 and C=C of vinyl at 1466 cm -1 [10,27]. The cholesteric monomer (M-2) shows characteristic peaks corresponding to C-H stretching of vinyl at 3018 cm -1 , C-H of methylene at 2945 cm -1 , C=C of vinyl at 1457 and 1369 cm -1 .…”

“…The spectra for the network polymers (e.g. L-1) formed after 12 h reaction show the complete disappearance of the peaks for the Si-H stretching at 2160 cm -1 and vinyl C=C stretching at about 1466 cm -1 of the monomers [10,27]. …”

Silicone‐based cholesteric liquid crystalline polymers: Effect of crosslinking agent on phase transition behavior

“…Thus with the addition of x‐linking agent, X c decreases regularly. The peaks near 2θ = 10.2 and 22.5° are due to formation of the crystals in two different directions which correspond to (110) and (200) reflections, respectively 32. The crystallite size in both the directions decreases showing a reduced size anisotropy.…”

“…The cholesteric monomer (M‐2) shows characteristic transmittance peaks corresponding to CH stretching of vinyl at 3014 cm −1 , CH of methylene at 2937 cm −1 , CC of vinyl at 1465 and 1376 cm −1 and COC at 1211 and 1029 cm −1 . FTIR spectra of network liquid crystalline polymers formed after 12 h reaction show the complete disappearance of the peaks for the SiH stretching at 2160 cm −1 of PMHS and vinyl CC stretching at about 1475 cm −1 and 1465 cm −1 of the x‐linking agent (M‐1) and mesogenic monomer (M‐2), respectively 21, 32. This is only possible if the vinyl groups of M‐1 and/or M‐2 react with the SiH group of PMHS.…”

“…FTIR spectra of the crosslinking agent (M‐1), mesogenic monomer (M‐2) and LCP‐1 at the initial stage and after 12 h of reaction are presented in Figure 1. The FTIR spectra of M‐1 shows the characteristic transmittance peaks corresponding to CH stretching of vinyl at 3035 cm −1 , CH of methylene at 2925 and 2850 cm −1 , alkane ester group (RCOOR) at 1733 cm −1 and CC of vinyl at 1475 cm −1 21, 32. The cholesteric monomer (M‐2) shows characteristic transmittance peaks corresponding to CH stretching of vinyl at 3014 cm −1 , CH of methylene at 2937 cm −1 , CC of vinyl at 1465 and 1376 cm −1 and COC at 1211 and 1029 cm −1 .…”