萘酞菁LB膜取向液晶研究

利用二(3-叔丁基硅氧基)萘酞菁硅 (SiNc) Langmuir-Blodgett (LB) 膜对丝状液晶的定向进行了研究，发现在不同膜压下沉积的SiNc LB膜具有不同的定向效果.在15mN/m低膜压下沉积的LB膜上丝状液晶主要呈沿膜面水平排列，而30mN/m高膜压下沉积的LB膜则取垂直膜面取向.原子力显微镜(AFM)对相应的LB单层膜和多层膜进行的分子尺度上的形貌研究发现，高膜压条件下SiNc分子以分离的单体或聚集体形式非连续地在基片上呈线性堆积排列，形成一定的分子“纳米线”，并且大环平面垂直于基片 关键词：

THE ALIGNMENT EFFECT OF NAPHTHALOCYANINE LB FILMS ON LIQUID CRYSTALS

Bis (trimethylsiloxy) silicon naphthalocyanine (SiNc) LB films were fabricated to align nematic liquid crystals. Films obtained under different surface pressures exhibit different alignment effects. Films obtained under surface pressure of 15mN/m will induce a planar alignment, while those obtained under 30mN/m will induce a homeotropic alignment. Atomic force microscopy reveals that on films prepared under high surface pressure the SiNc molecules stack into separate monomers or aggregates to form lines of nanometer size with molecular macrocycles perpendicular to the surface of the film and the dipping direction of its formation. In addition, there are grooves of molecular size between the stacked SiNc molecular lines. Similar formation occurs in films prepared under low surface pressures, only instead of molecules all lying perpendicular to the surface, many SiNc molecules are lying obliquely to the film surface or even lying on the surface. The mechanism of the liquid crystal alignment is also discussed.