[The dynamics of electric-field-induced molecular reorientation and segmental mobility in the antiferroelectric LCs studied by time-resolved FTIR spectroscopy].
We employed dynamic and polarized infrared spectroscopy to monitor the response of different molecular segments to external electric fields. Measurements of absorbance changes of the representative IR bands as a function of the polarization rotation angle at 109 degrees C under DC electric fields of 0.15 and -15 V determine mutual arrangement of different molecular segments in their equilibrium state in the helicoidal Sm-CA* phase (0 V) and field-induced, unbound Sm-C phase (15 and -15 V). It is clear from the normalized absorbance changes dAn vs wave electric field at 5 KHz repetition rate that the different segments complete the reorientation at different time scales. The core moves faster and takes approximately 33 microseconds to complete the reorientation, while it takes approximately 64 microseconds for the alkyl chains and the C=O group.
Zhao
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B
Key Laboratory of Supramolecular Structure and Spectroscopy, Jilin University, 130023 Changchun.
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Ozaki
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Y