I synthesized ester derivatives of cholesterol. The derivatives characterized by polarized optical microscope(POM) and deferential scanning colarimetry(DSC) but i do not know how to analyze the charts.The derivatives may be have liquid crystals properties.
In my opinion, you should find the viscosity of your material and then analyze the charts. Also, you might need to make a prediction of what you expected to see. check the link below it may help you.
http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=-859496303&_sort=r&_st=13&view=c&md5=77866b742bb39ec9cf86669096dc497f&searchtype=a
Dear, this analysis depends on the texture of internal structure that appear in POM, and then select the type such as nematic, semactic (A,B,...etc.) or cholesteric because each phase has a many properties distinguish from other. For more information you can download (Texture of Liquid Crystal) handbook.
Dear Ahmed:
There are two basic techniques you can use, polarized light microscopy (POM) and differential scanning calorimetry (DSC). Both, you can see phase transition between solid-liquid crystals-isotropic liquid.
Best regards
You may possibly find useful refer to: Xin-Jiu Wang, Qi-Feng Zhou, "Liquid Crystalline Polymers", World Scientific, 2004, cf. Ch. 4 entitled "Characterization of liquid crystalline polymers".
http://www.worldscientific.com/worldscibooks/10.1142/5309
If you have already performed POM observation, you might have got some idea regarding whether or not a liquid crystalline phase occurs. Most liquid crystalline phases are manifested in POM textures in one of the focal conic textures like mosaic, maltese crosses, oily streaks, fanlike, white birefringence, etc. Among them, fanlike texture is due to hexagonal LC and others are due to different forms of lamellar bilayers (smectic). However, if the LC phase is cubic, POM does not give birefringent texture. DSC is a major instrument to quantitatively know the phase transition behaviors of LCs, but it alone, can not tell whether the phases are LC or any particular kind of it. The best and comparatively easier technique to confirm the exact structure of LCs (as long as you do not need much detailed understanding of many LC parameters) is small angle x- ray scattering (SAXS). The SAXS measurement yields characteristic diffraction patterns for different types of LC and preliminary idea about the LC structures is acquired from the SAXS peak ratios.
Hello!
To characterize the properties of the LC phase you can estimate the parameters of the dielectric anisotropy, the coefficients of elasticity, viscosity, concentration of mobile ions.
The following articles will help you in this, because they contain a lot of information about the measurement of properties mentioned above
Article Study of dynamics and relaxation optical response of nematic...
Conference Paper M. A. Kurachkina ; D. P. Shcherbinin and E. A. Konshina " Sp...
Article Impact of Doping CdSe/ZnS Quantum Dots on the Elasticity Coe...
Article The Effect of CdSe/ZnS Quantum Dots on the Rotational Viscos...
Polarized optical microscopy is typically used to detect the existence of liquid crystal phases in a solution as liquid crystal phase exhibits its unique texture under microscopy.
Polarized Optical Microscope (POM) is used to identify the mesophase of liquid crystals. Isotropization (no textures) temperature was determined by DSC . By cooling from isotropiration temperature Nematic Semetic etc phase was determine from the analysis of texture.
Liquid crystalline materials can be analyze by POM and DSC. Different LC phases can be detect by POM and also XRD for different phases.
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