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通过控制溶液浓度,溶剂蒸发温度,溶剂蒸发环境3种结晶条件,利用简单的溶液涂膜方法从热力学的角度深入探究了聚偏氟乙烯(PVDF)各晶相产生的原因以及各晶相的相对含量与结晶形貌之间的关系。结果表明,由于构象是热力学稳定状态,β和γ相是不稳定状态,较低的成核速率利于相结晶,而较高的成核速率通过改变动力学路径使系统停留在较高能量的亚稳态,即β和γ分子构象。在本实验条件范围内,10%的溶液在60℃的加热板上结晶可以获得82%的极性相,30%的溶液在室温或者40℃的烘箱中结晶可以获得100%的极性相,主要为γ相。此外,低温下溶剂分子与PVDF分子之间较强的相互作用也从能量角度解释了极性相产生的原因。
By controlling the solution concentration, the solvent evaporation temperature and the solvent evaporation environment, the reasons of each crystal phase of PVDF and the relative phase of each crystal phase were investigated by the simple solution coating method from the thermodynamic point of view Relationship between content and crystalline morphology. The results show that since the conformation is thermodynamically stable, the β and γ phases are unstable, the lower nucleation rate favors phase crystallization, and the higher nucleation rate allows the system to stay at a higher energy level by changing the kinetic pathways Steady state, ie the beta and gamma molecular conformations. Within the experimental conditions, 10% of the solution crystallized on a hot plate at 60 ° C to obtain 82% of the polar phase, and 30% of the solution crystallized in the oven at or around 40 ° C to obtain a 100% Mainly γ phase. In addition, the strong interaction between the solvent molecules and the PVDF molecules at low temperature explains the reason of the polar phase from the energy point of view.