Abstract:

The authors studied a new polymer network liquid crystal (PNLC) system of  the polymer  dissolved in  N\|(4\|methoxybenzal)-p-butylaniline (MBBA) liquid crystal. The dissolved polymer which did  not require light radiation,  formed spontaneously a   polymer network structure   in the system. Phase grating was engraved on the polymer network via  double\|beams interference method. The differences of the conditions and morphologies of the  Williams domains in the MBBA liquid crystal before and after doping the polymer were  compared. Polymer network structure made the signal frequency of the formation of Williams domains in the MBBA liquid crystal raise from 50.3 Hz to 622 Hz. In the case of without doping the polymer,  Williams domains in the MBBA liquid crystal begin to disappear when the  signal frequency is 65.9 Hz, but Williams domains in the MBBA liquid crystal don’t disappear  when the polymer network structure exists, hence  improving the stability of liquid crystal orientation. Moreover, the phase grating  engraved on the polymer network and the phase grating   formed in the MBBA liquid crystal under the influence of an electric field don’t interfere with each other.

Key words: polymer network liquid crystal, phase separation, Williams domain, phase grating