Synthesis And Properties Of Novel Low Viscosity Difluorooxymethylene-Bridged Liquid Crystals Compounds

With the rapid development of LCD technology , TFT-LCD has become the mainstream in liquid crystal displays, but the problems of video animation blur,streaking,etc.remain unresolved, which is due to the slow response speed of LCDs.The viscosity of liquid crystal material directly determines the response speed of LCDs. Therefore, it has been attracted great attention for developing new liquid crystal materials with low viscosity.Difluoro sub methoxy is a class of fluorinated liquid crystal compounds developed in 1980s . The introduction of fluorinated functional groups can significantly reduce the viscosity and the response time of LCDs, which is of benefit to low-temperature performance of LCDs. Therefore, difluoro sub methoxy is one of the most prominent compounds found in recent years with the salient overall performance.The paper has designed and synthesized nPTPdFOPF, nPTPdFOGF and nUPdFOPF three series which are total 11 two fluorine sub-methoxy classes of LCD compounds, are not reported in the literature.Through 1H NMR, 13C NMR, 19F NMR, MS, IR spectra characterizing compound structure is confirmed . By ( DSC ) measuring the phase-change temperatures , shows that there are obviously LCD properties and morphology is wide , with the introduction of fluorine atoms lateral status , melting point and clearing point have significantly reduced. Through the AR500 liquid rheometry measuring temperature curve of compounds viscosity changing with temperature, and the results show that the viscosity of two fluorine sub-methoxy class liquid crystal compounds,is very tiny in low temperature, comprehensive performance is very excellent.