In-situ Spectra Studies On Condense Structure Evolution Of Biopolymer/Conductive Polymer Induced By Solvent Vapor

Time-resolved measurement of FT-IR has been performed to monitor in-situ thecondense structure evolution of biopolymer/conductive polymer induced by solventvapor with the self-made experimental accessory at room temperature. The resultsshowed that PLLAα′form was induced by all various solvent types, while the abilityof crystallization is different, and the order of infrared crystallinity calculated from theIR spectra is chloroform＞acetone＞THF＞ethyl acetate＞alcohol＞toluene. Theresults show that the closer solubility parameter between solvent and PLLA will leadto the higher crystallinity. The relationship between crystallization rate and theamount of solvent is not positive correlation, while it exists the optimum amount. Thecrystallization shows that solvent diffusion is the Fick diffusion behavior at its initialstage. The PLLA crystallization is homogeneous nucleation, and its Avrami index is2,corresponding to two-dimensional diffusion-controlled growth mode. With thetemperature increases, crystallization rate is accelerated, and the activation energy Eafor PLLA crystallization is146.1×10³J/mol K.The phase transition of P3OT induced by CS₂experiences three stages, from thesolid state to solution and then solid again. With the relevant three images ofmicro-infrared obtained, we may conclude that the evaporation rate of CS2controlsthe crystal morphology of P3OT. Calculated by the Avrami equation, we learn that thelater crystallization stage of P3OT during the phase transition induced by CS2,belongs to homogeneous nucleation, corresponding to a two-dimensionaldiffusion-controlled growth mode.