Fast Crystallization Of Liquid Crystals And Polymers By Ultra-fast Chip Calorimeter And Raman Microscopy

In this thesis, a recently developed chip calorimetry-ultrafast differential scanning calorimetry (UFDSC) is introduced and has been used to study the transient polymorph transition of the liquid crystal8OCB with the heating and cooling rates up to20000K/s. The square plate form (SP), which was reported to grow only from the solution in binary solvent mixtures at low temperature, is found to be the only form growing from a deeply quenched smectic glass during very rapid heating. If the heating rate is slower than8000K/s, reorganization to parallelepiped form will start, and if the heating rate is slower than1000K/s, the square plate form will reorganize to parallelepiped form completely, and only melting of parallelepiped form is observed.To get more information of metastable structures and behaviors of polymorph transtions or some other phase transitons, we need to combine the chip calorimetry with other technologies. So that we developed the hot-stage ultrafast differential scanning calorimetry which make in situ observation possible.With the hot-stage ultrafast differential scanning calorimetry combining Raman microscopy, we studied the isothermal crystallization of PET and found that it has a rapid crystallization rate when annealed at450K. We can find that the crystallization starts from5s and almost finished within100s either in ultrafast differential scanning calorimetry or from the vibrational analysis in Raman spectra. The great agreement of the results from this two kinds of technologies makes us believe that the technological combination should bring out better understanding of nucleation, crystallization and phase transitions of molecule systerms, e.g. simple molecule compounds, polymers, biominerals and pharmaceuticals and so on in the future.