The surface rubbing effect on morphologies of LC droplets and electro-optic properties of flexible PDLC films

Abstract

The flexible polymer dispersed liquid crystal (PDLC) film with threshold voltage V10 and saturation driving voltage V90 as low as 0.34 V/μm and 0.77 V/μm, respectively, has been prepared successfully by polymerization induced phase separation (PIPS). The surface rubbing effect on morphologies of liquid crystals (LC) droplets and electro-optic properties of PDLC films has been studied experimentally and theoretically. We use a CVC (Color Video Camera) and a SEM (Scan Electron Microscope) to detect and characterize morphologies of LC droplets in the net of polymer. The result reveals that almost all the smaller LC droplets exhibit in the rubbing direction uniformly, and the texture of PDLC is similar to that of H-PDLC. Meanwhile, compared with the sample of the non-rubbing disposal, the response time declines evidently by 11.2 ms (i.e., the rising time τrise) and 27.2 ms (i.e., the decaying time τdown), and the contrast ratio is improved from 18.5 to 35.9. Such a result can be attributed to the surface rubbing effect.