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| Effect of chain rigidity on the flow of macromolecular solution in micro-and nanochannels |
| XU Shao-feng, WANG Jiu-gen |
| Department of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China |
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Abstract Dissipative particle dynamics (DPD) approach was used to investigate effect of chain rigidity on the pressure driven flow of macromolecular solution in micro-and nanochannels. The macromolecules were modeled with worm-like chains. The effect of chain rigidity on the velocity field in the channel. and the cross-streamline migration of macromolecules were studied. The results show that the flow resistance of chains increases with increasing chain rigidity, which can reduce the velocity of the fluids around the chains, thus the velocity of macromolecular solution in the channel decreases. The DPD simulation results also show that the chains migrate toward the channel centerline with small chain rigidity in the pressure driven flow, and both the migration toward the channel centerline and the thickness of depletion layer near the wall increases with the flow strength. However, with the increase of chain rigidity, the depletion layer at the walls decreases and the macromolecular concentration at the channel centerline also decreases, thus the bimodal distribution of chain center-of-mass becomes more pronounced. These simulation results are agree well with the experimental observations and can be used to design and optimize micro-and nanofluidic devices.
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Published: 01 August 2014
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链刚性对高分子溶液在微纳通道内流动的影响
采用蠕虫状链（worm-like chain）模型表示高分子链,用耗散粒子动力学（DPD）方法模拟微纳通道内高分子溶液的压力流,研究链刚性对高分子链迁移以及通道内速度场的影响.研究结果表明,链刚性越强,高分子链受到的阻力越大,降低高分子链周围流体的速度,使高分子溶液整体流速减小.模拟结果还显示,当链刚度较小时,高分子链在微通道压力流中会向通道中心方向迁移,并随着流场增强迁移越明显,但随着链刚性增强,壁面附近的高分子链排空层厚度减小,通道中心处的高分子链浓度也减小,高分子链质心分布呈明显的双峰状,与实验结果吻合.模拟结果对相关微纳流控机械的设计和优化具有指导意义.
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