Synthesis And Properties Research Of Side Chain Liquid Crystalline Olymers Containing Azobenzene

Side Chain Liquid Crystalline Polymers Containing Azobenzene has great applicationprospect as functional materials in liquid crystal display、records storage medium,photoelectric conversion and so on. It is still an important part of current research thatdesigning and synthesizing new types of liquid crystal polymers to understand the relationshipbetween the structure and the properties of the liquid crystal. According to the Xinjiu Wangand Warner’s theory (W-W’s theory), the model of Side Chain Liquid Crystalline Polymerswith Azobenzene was designed. Then a series of Side Chain Liquid Crystalline PolymersContaining Azobenzene were got through the change of Flexible Space、Rigidity Unit andEnd Group in the structure of mesogenic unit: compound 1～6. Among them: compound 2had a longer flexible chain (-CH2CH2CH2O-) compare to compound 1; Compound 3 had onemore rigid benzene (Ar) compare to compound 2; Compound 4, compound 5 and compound 6had different end groups: SO3H、NO2、COOH respectively. The six compounds above hadprogressive relation in molecular design to research the influence between the molecularstructure changes and properties.The structure of the serie compounds were characterized by IR, then the texture wereobtained by Polarizing Observations Microscopic (POM), and found that they were allsmectic liquid crystal with different texture. Thermal properties (Tm-Ti) had been performedby using Differential Scanning Calorimeter (DSC), compound 1: 148.34～210.66℃;Compound 2: 140.51～192.67℃; Compound 3: 176.14～230.09℃; Compound 4: 191.04～274.95℃; Compound 5: 155.558～226.381℃; Compound 6: 164.68～251.61℃, finally therelationship between the molecular structure changes and properties were summarized.It showed that: (1) In the condition of similar molecular structure framework, the slightchange would not affect the crystalline form but the texture would be largely changed. (2) The embedded of the flexible chain would reduce the melting point and isolate point of the liquidcrystal compounds, and phase change interval would be reduced accordingly. (3) The increaseof the rigidity unit in liquid crystal compounds would raise the melting point and isolate point,but little change in phase change interval. (4) The different polarity of end group wouldinfluence the phase transition temperature, it was the combined affection of the end grouppolarity, hydrogen bond and the spatial effect.