论文标题
聚合物晶体的成核屏障纠缠
Entanglement on nucleation barrier of polymer crystal
论文作者
论文摘要
我们提出了一种理论方法来定量说明纠缠在聚合物融化成核中的作用，这是与小分子区分的聚合物的独特特征。通过执行分子动力学模拟，我们获得了具有不同纠缠密度的聚合物系统的成核屏障，与经典成核理论（CNT）的预测相比，这表现出相反的趋势。为了修改CNT在聚合物结晶中的缺乏，我们引入了纠缠自由能，以反映纠缠中的作用在聚合物成核中。具体而言，聚合物成核不仅涉及CNT中所考虑的核内外单体的自由能，而且还会影响核周围的纠缠网络。我们的理论方法为在模拟和实验中未解决的聚合物的未解决成核现象提供了合理的解释。
We propose a theoretical approach to quantitatively account for the role of entanglement in the nucleation of polymer melts, which is the unique feature of polymer differentiated from small molecules. By performing molecular dynamics simulations, we obtain the nucleation barriers of polymer systems with different entanglement densities, which exhibits an opposite trend compared to the prediction of the classic nucleation theory (CNT). To amend the deficiency of the CNT in polymer crystallization, we introduce the entanglement free energy to reflect the role of entanglement in polymer nucleation. Specifically, the polymer nucleation not only involves free energies of monomers inside and on the surface of a nucleus as considered in the CNT, but also affects the entanglement network around the nucleus. Our theoretical approach provides a reasonable interpretation for the unsolved nucleation phenomena of polymers in simulations and experiments.
