自由基引发的凝胶化反应的Monte Carlo模拟

MONTE CARLO SIMULATION OF RADICAL INITIATED GELATION

基于自由基凝胶化反应的基本原理，在一个具有周期性边界条件的二维网络上，利用动态ＭｏｎｔｅＣａｒｌｏ 方法模拟了聚合物凝胶的自由基凝胶化反应，得到了凝胶的具体结构，研究了总单体浓度（ 单体浓度和交联剂浓度之和） 对凝胶的分形结构和孔径分布的影响．模拟中首次考虑了聚合后单体的运动对凝胶结构的影响．结果表明：考虑聚合后单体的运动，可使所得凝胶网络的分形维数和凝胶化所需的最低浓度均显著小于动力学凝胶化模型和ＤＬＡ 模型的相应值．用移动气泡法得到了凝胶网络的孔径分布，发现凝胶网络中大孔所占百分率明显多于随机纤维网络模型．

The complex structure of polymer gels was studied with dynamic Monte Carlo simulation based on the principle of gelation theory in a 2D network with periodic condition. The effect of polymerized monomer's (monomers of polymer) movement on the structure of polymer gels was studied. Simulation results indicated that the threshold concentration of gelation and the fractal dimension of polymer gels could be considerably decreased compared with the kinetic gelation model and the DLA model when polymerized monomers were allowed to move, especially when the total monomer concentration is low. The pore size distribution was acquired by moving bubble method. It was found that the ratio of big pores in our gel network was higher than that based on the Ogston's model.That indicates the simulated gels was of great inhomogeneity.