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.
As a powerful macrocyclic host molecule with unique conformation and cavity structure that are fine-tuned by the bridging nitrogen atoms, methylazacalix[4]pyridine (MACP-4) has been shown to selectively recognize Zn2+ and form stable Zn(Ⅱ)-MACP-4 complexes both in solid state and solution with an association constant up to 5.97 (logKs). The molecular recognition of Zn(Ⅱ)-MACP-4 complexes towards various amino acids and anions with different geometry was investigated by using the spectral titration methods and X-ray analysis. The Zn(Ⅱ)-MACP-4 complex was found to recognize the 17 amino acids tested with the association constant up to 3.97 (logKs). On the other hand, the Zn(Ⅱ)-MACP-4 complex selectively interacted with anions and the maximum association constant of 3.9 (logKs) was obtained.
GONG HanYuan, WANG DeXian, HUANG ZhiTang & WANG MeiXiang Beijing National Laboratory for Molecular Sciences, CAS Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
