Multiscale understanding on the membrane formation process via thermally induced phase separation
A new methodology that combines dissipative particle dynamics (DPD) method on the mesoscale with a Maxwell-Stefan (MS) model on the macroscale has been established to investigate the dynamics of hollow fiber membrane formation process via TIPS, taken the polyvinylidene fluoride-diphenyl carbonate (PVDF-DPC) system into account.Firstly, the MS model was established to describe the mass and heat transfer in the air gap and coagulation bath stages during TIPS process.The concentration and temperature profiles of the polymer solution were obtained and then the effects of the evaporation time which relates with the air gap distance, quenclhing time and initial polymer concentration on the profiles were analyzed in detail.Secondly, a novel simulation methodology based on DPD and the results of the MS model was developed to obtain multiscale understanding on the membrane formation process.The simulated phase separation process by this methodology could be close to a real membrane formation process by adopting a linear cooling algorithm based on the macroscopic MS model results and implementing the DPD simulation on a single graphics processing unit (GPU) to provide a much faster computation speed and larger scales.The simulation results indicated that the temperature gradient in the polymer solution caused that different parts in the polymer solution possessed different cooling rates and coarsen time, which resulted in a microporous membrane with anisotropic structure.Finally, the membranes are prepared to validate the model results.
Thermally induced phase separation Dissipative particle dynamics Maxwell-Stefan model Heat transfer Mass transfer
Han-Han Lin Yuan-Hui Tang Xiao-Lin Wang
Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P.R.China
国内会议
江西上饶
英文
75-82
2016-08-01（万方平台首次上网日期，不代表论文的发表时间）