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提出了剪切流中高分子链在微通道内的迁移机制.该机制采用珠-簧链模型表示高分子链,高分子链受剪切作用而被拉伸,相邻珠子之间的流体力学相互作用产生了对称的扰动流场,由于在通道壁面附近对称的流场被破坏,壁面与高分子链间的流体力学相互作用使高分子远离壁面,在强受限时,这种壁面诱导的流体力学相互作用会被屏蔽掉.利用耗散粒子动力学数值模拟了高分子链在微通道压力流中的迁移行为.数值模拟结果表明,在受限较弱时,高分子链向远离壁面的方向迁移,并随着流场增强,远离壁面的趋势越强;在受限较强时,高分子链不会发生远离壁面的行为.实验研究了长链高分子λ-DNA在壁面附近的迁移行为,实验结果及模拟结果与迁移机制预测的结果相吻合,验证了迁移机制的正确性.高分子链浓度会影响高分子链的迁移行为,当高分子链浓度较大时,高分子链在通道宽度方向不会发生迁移现象,意味着随着浓度的增大,壁面与高分子链间的流体力学相互作用会逐渐被屏蔽.
The migration mechanism of polymer chains in microchannels in shear flow is proposed.The mechanism uses bead-chain model to represent the polymer chains, the polymer chains are stretched by shearing action, the fluid dynamics between adjacent beads The symmetrical perturbation flow field is generated. Due to the destruction of the symmetrical flow field near the channel wall, the hydrodynamic interaction between the wall and the polymer chain causes the polymer molecules to move away from the wall surface. When the force is limited, the wall-induced fluid Mechanics interaction is masked.Microphase dynamics is used to simulate the migration of macromolecule chains in microchannels pressure flow.The numerical results show that in the weaken the polymer chain moves away from the wall Migrated, and the stronger the flow field, the stronger the trend away from the wall; in the limited strong, the polymer chain will not occur far away from the wall behavior.Experimental study of long-chain macromolecule λ-DNA in the wall near the migration behavior , The experimental results and simulation results are in good agreement with the prediction results of the migration mechanism to verify the correctness of the migration mechanism.The concentration of the polymer chain will affect the migration behavior of the polymer chain.When the concentration of the polymer chain is large, Migration does not occur in the channel width, which means that as the concentration increases, the hydrodynamic interaction between the wall and the polymer chain will be gradually shielded.